CivilEng doi: 10.3390/civileng7020032

Authors: Yupeng Ou Pingan Liu Youlin Chen Tiehu Wang Xiang Liu Xun Zhang

Fault-crossing ground motions, characterized by velocity pulses, permanent fault dis-placement, and non-uniform support excitation associated with fault rupture, may significantly affect the seismic performance of siphon bridges crossing active faults. This study investigates a long-span siphon arch bridge subjected to pulse-type fault-crossing ground motions. A unified stochastic ground motion model is developed by integrating nonstationary high-frequency components based on the evolutionary power spectrum with low-frequency pulse components represented by an improved Gabor wavelet, capturing forward directivity effects, permanent displacement, and differential support input at the two sides of the fault. A three-dimensional nonlinear finite element model is established in OpenSees using fiber-based beam–column elements, with hydrodynamic effects incorporated through the added mass method. Parametric analyses consider pulse phase angle (0–90°), amplitude (Mw 6.0–7.5), and frequency (0–1 Hz). Results indicate that structural responses decrease with increasing phase angle, with 0° being most unfavorable, high-lighting the dominant influence of permanent displacement. Resonance amplification occurs when pulse frequencies approach the fundamental modes of the pier (0.345 Hz) and deck (0.51 Hz), while the arch is particularly sensitive near 0.439 Hz. Water added mass reduces natural frequencies by 8–14% and significantly amplifies internal forces. These findings provide guidance for seismic design of fault-crossing siphon bridges.

CivilEng doi: 10.3390/civileng7020031

Authors: Peter Ghoche Bernard Lavoie Maryam Kamali Nezhad Georges Abdul-Nour

Factors such as asset aging, climate change affecting hydrological events, and the growing demand in electricity are placing huge pressure on hydroelectric infrastructure—in particular, hydroelectric dams, whose most important and critical component is the spillway, which operates through a system of discharge gates. This research aims to present the technical, environmental, and functional parameters and issues affecting this system, highlighting the causes of their degradation and proposing solutions to improve their service life and their reliability. A literature review has been undertaken to identify the challenges related to the reliability and durability of the system. In addition, a case study based on real-world data was made to support and reveal the problems related to the spillway gates system. What sets this research apart is its integration of theoretical studies with a practical case study, supporting the proposed theories and uncovering potential hidden factors. Following the identification of key challenges, new updated and adaptable solutions explored world-widely are recommended to be developed in future research.

CivilEng doi: 10.3390/civileng7020030

Authors: Vassilios Aggelidis Costas A. Anagnostopoulos

The aim of this research was to evaluate the efficacy of water-soluble epoxy resin (ER) in regard to stabilising clay soils, specifically for the design of column-type reinforcement in soft ground. An extensive laboratory program was conducted to assess the mechanical enhancement of a silty clay soil via ER, both as a standalone stabiliser and in combination with cement, bentonite, and sodium polyacrylate (PA). In addition, the study investigated the impacts of thermal stabilisation and electro-osmotic dewatering on resin–soil specimens. Specimens stabilised solely with ER exhibited poor strength development due to the inhibition of polymerisation by water. The addition of bentonite at low concentrations resulted in low early strength development and a moderate increase in the final strength. The use of cement provided the most significant strength gains, which were further enhanced by optimising the dosage of PA, although an excessive PA content significantly reduced the strength properties. In terms of physical treatments, thermal stabilisation at an optimal temperature of 60 °C for 24 h substantially improved the performance of ER. Electro-osmotic treatment accelerated the development of early strength but failed to provide appreciable strength improvement, and resulted in brittle behaviour and reduced toughness in the later stages (90–180 days). These findings offer critical guidelines for optimising mix designs and treatment protocols for geotechnical ground improvement projects.

CivilEng doi: 10.3390/civileng7020029

Authors: Tianwen Dong Nobuaki Hanai Toshiyuki Kanakubo

In various countries, the shear-strength design formulas for reinforced concrete beam–column joints are primarily constructed based on concrete strength, and the influence of the main bars of the beam is not explicitly reflected in these expressions. To address this limitation, this study examines the shear behavior of the joint, focusing particularly on the amount and arrangement of the main bars of the beam passing through the joint. Four beam–column joint specimens were tested under cyclic loading. The main variables of the specimens were the amount and arrangement of the main bars of the beam. The detailed strain measurements were conducted to clarify the development of bond deterioration along the main bars and the associated internal force transfer mechanisms. The experimental observations revealed significant tension-shift phenomena and progressive bond deterioration in the compression-side main bars. Within the scope of the present test series, variations in the amount and arrangement of the main bars of the beam did not significantly affect the maximum applied load. However, the indirectly evaluated joint shear force was higher in specimens with two layers in the main beam bars. Force equilibrium using force components obtained by measured strain produced even larger values at greater drift angles, indicating that joint shear assessment depends strongly on the evaluation basis. A mechanics-based diagonal strut model incorporating the internal compression field provided improved agreement with experimental results, confirming its applicability for practical design.

CivilEng doi: 10.3390/civileng7020028

Authors: Maria Pomoni

Traditional road geometric design is based on assumptions regarding human perception and reaction, which directly influences Stopping Sight Distance (SSD) and the associated design parameters of vertical curves. Under a future scenario of full autonomous vehicle (AV) deployment, reduced perception–reaction times and modified sensing configurations may change visibility-controlled design requirements. This study presents a structured parametric assessment of SSD and vertical curve lengths under the assumption of full AV operation. Variations are considered in reaction time, sensor height, sensor inclination angle, longitudinal grade, and vehicle operating speed. Default parameter values derived from current design standards, together with ranges reported in the literature, are used to evaluate the geometric implications of full vehicle automation within a controlled analytical framework. The results indicate that reduced reaction times and increased sensor heights of AVs may decrease required SSD values and consequently shorten crest and sag vertical curve lengths compared to conventional human-driven vehicle assumptions. For sag curves in particular, headlight inclination angle is revealed as a significant geometric variable. Overall, the study proposes a framework for examining the interaction between AV sensing characteristics and vertical geometric design, thereby providing a basis for future evaluation of design standards without directly prescribing modifications to current practice.

CivilEng doi: 10.3390/civileng7020027

Authors: Ivelin Ivanov Dimitar Velchev

The methodology described in Eurocode 8, Part 4, for calculating seismic effects on vertical cylindrical rigid and fixed steel storage tanks is programmed in MATLAB®. The walls of the tanks are constructed of shell courses with varying thicknesses of sheet material. The strength conditions for the ultimate limit states of plasticity, elastic buckling, and elastoplastic buckling (“elephant foot”) are checked at many calculation points along the height of the storage tank. The thicknesses of the courses are determined to satisfy all strength conditions for different slenderness ratios of the tanks and for different volume capacities. Tanks with supported roofs and those with self-supporting roofs are considered, as well as open-top tanks. A mass per unit volume capacity is the criterion for optimization for different seismic loadings and steel grades. The criterion is not a smooth function because of the discrete thicknesses of the shell courses and their number. A smooth objective function is created for better parametric optimization analysis. The dependence of the optimal slenderness ratio on the volume capacity is determined, as well as the inverse dependence. The problem of the optimal number of storage tanks in a set of tanks with a given total volume capacity is also considered.

CivilEng doi: 10.3390/civileng7020026

Authors: Mana Dastoum Yasmine Mahmoud Saad Abdelhamid Esraa Elareef Carmen Sánchez-Guevara Beatriz Arranz Reza Askarizad

Despite the growing use of tessellated and patterned façades in contemporary architecture, their thermal performance, particularly in cooling-dominated educational buildings, remains insufficiently quantified, with existing studies largely prioritizing daylighting or aesthetic outcomes over energy-driven thermal behavior. This study aims to systematically evaluate how different tessellated façade geometries and perforation ratios influence thermal performance and cooling demand in a Mediterranean climate, and to identify an optimal façade configuration that balances multiple thermal objectives. Three tessellation typologies—nature-inspired (Voronoi), Islamic geometric, and folded origami-based patterns—were parametrically generated and applied as external shading screens to an educational building. Annual thermal simulations were conducted using Climate Studio to assess four performance metrics: solar heat gain, energy use intensity, hours of overheating derived from operative temperature, and peak cooling demand. A post-simulation, data-driven, multi-objective, decision-support approach was applied using Compromise Programming to systematically evaluate and rank discrete façade alternatives based on multiple thermal performance criteria. Results indicate that all tessellated façades reduce solar heat gain and peak cooling demand relative to the unshaded baseline, with performance strongly dependent on both geometry and perforation ratio. Lower perforation ratios (20%) consistently outperform more open configurations, while Voronoi-based façades achieve the most balanced overall thermal performance across all evaluated criteria and emerging as the top-ranked solution. The study’s novelty lies in its comparative, cooling-focused evaluation of fundamentally different tessellation logics using transparent, decision-oriented optimization rather than subjective comfort indices or computationally intensive evolutionary algorithms. Beyond its specific findings, the research provides a transferable methodological framework for integrating geometry-informed façade design into early-stage decision-making, supporting climate-responsive and energy-efficient educational architecture in Mediterranean and similar climates.

CivilEng doi: 10.3390/civileng7020025

Authors: Zainab Al Qraiti Anmar Dulaimi Marisa Sofia Fernandes Dinis de Almeida Luís Filipe Almeida Bernardo

Comparing cold-recycled asphalt mixtures (CRAMs) to conventional hot-mix asphalt (HMA) shows that CRAMs offer several logistical, financial, and environmental advantages. However, such CRAMs, when using asphalt emulsion, still suffer from excessive water damage and poor early-age performance. The main aim of this study is to improve CRAMs by incorporating two biomass ashes and reclaimed asphalt pavement (RAP): palm leaf ash (PLA) and reed ash (RA) with different percentages of RAP. RAP was used in five percentage levels, 0%, 25%, 50%, 75%, and 100% by weight of mix, to develop the CRAMs. In addition, the improvement in CMA mechanical properties was assessed by incorporating PLA as filler replacement in five percentages, namely: 0%, 1.75%, 3.5%, 5.25%, and 7% by weight of aggregate. RA was used as an activator at 0.25%, 0.5, 1%, and 2% by weight of aggregate. The moisture susceptibility test, Indirect Tensile Strength Test (ITS), and Marshall test were used to assess the mechanical properties. The results obtained showed that the durability and mechanical properties of CMA are effectively enhanced with the addition of 1.5% PLA, 0.45% RA, and 5.5% Ordinary Portland Cement (OPC) as fillers. In addition, CRAMs with a higher percentage of RAP 75%, showed higher strength in terms of Marshall stability. These findings demonstrate that the studied CRAMs offer a reliable alternative for pavement applications, namely when sustainable and cost-effective materials are required.

CivilEng doi: 10.3390/civileng7020024

Authors: Kunal Mohinderu Sriram Aaleti Saahastaranshu R. Bhardwaj

Laminated bamboo (LB) has emerged as a promising sustainable structural material due to its rapid renewability, high strength-to-weight ratio, and favorable mechanical performance. Drawing on a comprehensive review of over 90 published experimental and analytical studies, this paper provides a critical synthesis of the structural behavior of LB, with emphasis on its compression, tension, flexure, shear, and creep responses. Reported mechanical properties exhibit variability, largely influenced by bamboo species, fiber orientation, processing methods, adhesives, lamination quality, and loading configuration. While LB demonstrates high tensile and flexural strengths comparable to or exceeding conventional timber products, pronounced anisotropy and brittle failure modes are consistently observed, particularly under shear and rolling shear loading. Recent studies on cross-laminated bamboo (CLB) highlight the significant role of interlaminar behavior and adhesive performance in controlling failure mechanisms, indicating that rolling shear capacities often govern the design of planar elements. Beyond mechanical behavior, this review synthesizes available research on thermal and fire performance. Emerging research on LB connections indicates that joint behavior often governs global structural performance, with strength and ductility strongly influenced by fastener type and embedment behavior. Key knowledge gaps are identified, underscoring the need for unified design frameworks to enable broader structural adoption of laminated bamboo systems.

CivilEng doi: 10.3390/civileng7020023

Authors: Hamid Nikzad Shinta Yoshitomi

This paper proposes a power-based optimization procedure to identify the optimal number and vertical placement of buckling restrained brace (BRB) outrigger systems for enhancing the seismic performance of core-wall-dominated benchmark model. The proposed method is validated using a nine-zone numerical model subjected to nonlinear time-history analysis implemented in MATLAB R2025.a (25.1.0.2943329). The optimization variables include the number and locations of outriggers as well as the stiffness of the BRBs, while the objective function is defined as the minimization of the maximum inter-story drift response. Outriggers are installed between zones 2 and 9, with each zone subdivided into five potential outrigger levels located 150 mm above the floor level, resulting in 40 potential outrigger placement scenarios. The total number of outriggers is constrained to range from one to eight, with at most one outrigger allowed per zone. Optimal outrigger–BRB configurations are identified by incrementally distributing BRB stiffness at the perimeter column-outrigger connection regions using a power-based allocation strategy. At each optimization step, the proposed framework evaluates only one candidate configuration per eligible story and outrigger level, resulting in several nonlinear time-history analysis grows linearly with the number of candidate locations. This contrasts with the combinatorial growth in computational demand typically associated with exhaustive or evolutionary optimization methods and leads to a significant reduction in overall computational efforts.

CivilEng doi: 10.3390/civileng7020022

Authors: Hui Yao Jiaran Han Dandan Cao Xuhao Cui Min Wang Yu Liu

The dynamic modulus of asphalt mixtures is a key design parameter in pavement design, which significantly impacts the mechanical properties of asphalt pavements. This study simulated dynamic modulus tests of asphalt mixtures using the three-dimensional (3D) discrete element method (DEM) to investigate mechanical behaviors such as the loading-bearing ratio of individual aggregates. Fine-grained AC-13 and medium-grained AC-20 asphalt mixture models were randomly constructed in the DEM program using user-defined methods. The dynamic modulus and phase angle values of the asphalt mixtures were predicted. By comparing laboratory experiments with DEM simulation results, the model was validated, and the effects of temperature and loading frequency on the dynamic modulus were explored. Further exploration was conducted on the loading-bearing ratio and mechanical interactions among aggregates of different sizes within the mixtures. The results show that the 3D DEM model can accurately predict the dynamic modulus and phase angle of asphalt mixtures. Temperature and frequency have an impact on these parameters, and the increase in gradation has an impact on the loading-bearing ratio, due to the proportion of coarse aggregates.

CivilEng doi: 10.3390/civileng7020021

Authors: Shuaiyuan Wang Jianzhong Chen Yong Lv Pengfei Song Mingqing Sun

Three-edge bearing (TEB) tests and a crack-width-dependent load-carrying model were used to assess the combined effects of recycled glass fiber-reinforced polymer (rGFRP) short fibers and glass fiber-reinforced polymer (GFRP) bars in concrete pipes. Using the force method, a circumferential statically indeterminate ring analysis was formulated to obtain internal forces at critical sections and the neutral-axis position. Fiber distribution was simulated by means of Monte Carlo sampling, and single-filament pull-out tests were fitted to relate embedded length to pull-out force, enabling calculation of the fiber-bridging contribution at cracked sections. Ten specimen types with different bar/fiber schemes were tested under external pressure to validate the model. Predicted cracking and ultimate loads agreed with measurements, with most errors within ±20%. Adding 1% (vol.) rGFRP fibers increased the cracking load by 11.81% and the ultimate load by 0.45%. Without fibers, replacing steel bars with equal-area GFRP bars increased the cracking load by 1.35% but reduced the ultimate load by 35.45%. For all specimens, the load–maximum crack-width relation was strongly linear (R2 > 0.93). The proposed approach and dataset support engineering use of recycled GFRP materials for crack control and load-carrying design of concrete pipes.

CivilEng doi: 10.3390/civileng7020020

Authors: Vincenzo Sepe Mariella Diaferio Francesco Potenza

Historic masonry towers are all around the world and play a significant role in shaping our built environment. Due to their slender shape, these towers are particularly vulnerable, as recent earthquakes have demonstrated. Many researchers have studied how these structures behave dynamically, with the aim of preserving their cultural value against the risks of damage or collapse. Lately, considerable attention has been paid to develop empirical formulas that estimate their fundamental frequency by considering geometric factors such as total height, reference base length, and effective height for constrained towers. These formulas are usually obtained using regression analysis on data from the technical literature, and so their reliability depends heavily on both the quantity and precision of available data. The variables chosen for calibrating these correlations are mainly determined by the information present in the literature; as a result, missing data can lead to underestimating the influence of some geometric aspects. To address this issue, the paper describes parametric analyses with a simplified model of masonry towers, i.e., the Euler–Bernoulli beam, aiming to show how sensitive the fundamental frequency is to different geometric and mechanical properties. These analyses show the importance of some parameters with respect to others and support the planning of experimental investigation needed for accurate predictions of a tower’s fundamental frequency.

CivilEng doi: 10.3390/civileng7010019

Authors: Zihao Wang Zeqi Zhu

Active support systems are being increasingly applied in the control of large deformation in soft rock tunnels, and exploring the bearing characteristics of prestressed anchor bolts is of great engineering value for improving the long-term stability of tunnel structures. To address the problems of insufficient quantitative characterization of the bearing performance of prestressed anchor bolt support in soft rock tunnels and the difficulty of small-scale model tests in revealing the synergistic bearing law of support and surrounding rock, this study took a 350 km/h double-line high-speed railway tunnel as the prototype and established a large-scale tunnel structure model test system to conduct comparative tests under three working conditions: unsupported, ordinary bolt support, and prestressed anchor bolt support. By monitoring the tunnel failure process and mechanical response of the support structure throughout the test, the failure modes, bearing capacity, deformation characteristics, and axial force distribution of anchor bolts of tunnels under different support forms were systematically analyzed to quantitatively reveal the active support mechanism and bearing strengthening effect of prestressed anchor bolts. The results show that the design bearing capacity of the tunnel model with prestressed anchor bolt support is increased by 127.3% and 31.6% compared with that of the unsupported and ordinary bolt support models, and the ultimate bearing capacity is increased by 120.0% and 43.5%, respectively. Its secant stiffness in the initial loading stage reaches 80.0 kPa/mm, which is five times that of the ordinary bolt support and can effectively restrain the early plastic deformation of the surrounding rock. When the design bearing capacity is reached, the tensile stress of prestressed anchor bolts accounts for 40.2~69.8% of the ultimate tensile strength, with a more uniform axial force distribution and a much higher utilization rate of material mechanical properties than ordinary anchor bolts, which can fully mobilize the bearing potential of deep rock mass and realize the synergistic bearing of support and surrounding rock. This study accurately quantifies the bearing strengthening law of prestressed anchor bolts on tunnel support systems and clarifies the core mechanism of their active support. The research results provide important experimental basis and theoretical reference for the optimal design and engineering application of prestressed anchor bolts in soft rock tunnel engineering.

CivilEng doi: 10.3390/civileng7010018

Authors: Deelaram Nangir Michaela Gkantou Ana Bras Georgios Nikitas Maria Ferentinou Mike Riley Paul Clark Simon Humphreys

The UK faces an urgent challenge to simultaneously accelerate housing delivery and reduce whole-life carbon emissions, yet robust empirical evidence on the carbon performance of modular steel housing remains limited. This study aims to quantify the carbon impacts of a modular light-gauge steel frame social housing dwelling in the UK and to benchmark its performance against contemporary low-carbon construction typologies. A cradle-to-grave life cycle assessment was conducted using primary project data from a real modular housing development, with embodied carbon modelled in One Click LCA and operational energy assessed through SAP 10.2-verified datasets. The results indicate a total whole-life carbon footprint of 91.3 tCO2e over a 50-year period, with embodied emissions (A1–A3) accounting for 38.2% and operational energy and water use contributing 48.1%. The normalised embodied carbon intensity of 366 kgCO2e/m2 (A1–A5) is comparable to recent high-performing cross-laminated timber buildings, demonstrating that optimised modular steel systems can allow for low-carbon outcomes typically associated with bio-based construction. Sensitivity analysis shows that low-carbon foundation concrete, bio-based insulation, and steel optimisation can reduce upfront emissions by approximately 8–10%. Dynamic energy simulations were also used to assess how different design choices influence operational carbon emissions. This study provides transparent, real-project evidence of the whole-life carbon performance of UK modular light-gauge steel frame housing and identifies practical design strategies for further decarbonisation. The findings support informed decision-making for policymakers, designers, and housing providers seeking scalable, low-carbon residential solutions.

CivilEng doi: 10.3390/civileng7010017

Authors: Meng Xiang Yanping Niu Leilei Liu Xicheng Zhang Maozhe Nie Yao Cui

To effectively enhance the seismic performance of traditional Chinese timber structures, this study proposes a reinforcement method utilizing friction dampers. Based on the working mechanism of friction dampers and the extended discrete element theory, an analytical model for timber structures equipped with these dampers was developed and validated through shake table tests. Subsequently, dynamic analyses were conducted to systematically evaluate the enhanced seismic energy dissipation capacity of the ancient timber structures by the reinforcement of friction dampers. The friction coefficient (μ), bolt pre-tension strain (ε), and action distance (l) were selected as key parameters. A multi-objective optimization function was constructed using the weighted sum method, enabling a multi-objective parameter optimization analysis for the friction dampers to identify the optimal parameter combination under specific conditions. The results indicate that the established extended discrete element model effectively simulates the dynamic characteristics of the structure. The installation of friction dampers significantly enhanced the structure’s energy dissipation capacity and substantially reduced the peak displacement. However, due to the initial stiffness introduced by the dampers, the lateral stiffness of the column frame increased markedly, leading to a significant amplification of the acceleration response, with a maximum increase in peak acceleration reaching 77%. The multi-objective optimization analysis revealed that with weighting coefficients λa = λb = 0.5, the optimal damper parameter combination is μ = 0.36, ε = 102 με, and l = 268 mm. Under these conditions, the structural displacement response decreased by 38.5%, while the acceleration response increased by 93.7%. It is noted that the derived optimal design solutions are pertinent to the specific structural typology and ground motions considered.

CivilEng doi: 10.3390/civileng7010016

Authors: Seunghyun Na Wenyang Zhang Woonggeol Lee Madoka Taniguchi

Alkali-activated materials can significantly reduce carbon dioxide emissions compared with cement. However, their durability remains insufficiently understood. This study investigated the effects of calcium hydroxide (Ca(OH)2, CH), an expansion agent (calcium sulfoaluminate, CSA), and a shrinkage-reducing agent (SRA) on the compressive strength and length change and determined the optimal content levels for each agent. Experiments were conducted to evaluate the compressive strength and length change of 17 mortar mixtures containing CH, CSA, and SRA. The substitution ratios of CH, CSA, and SRA were fixed at three predefined levels for each factor. The microstructural changes induced by the use of each agent were analyzed using pH measurements, porosity analysis, and X-ray diffraction. In addition, the water desorption behaviors associated with CSA and SRA were assessed. Experimental and statistical analyses demonstrated that the optimal contents of CH, CSA, and SRA for simultaneously improving the compressive strength and length change were 8.54, 10.0, and 0.76 wt.%, respectively. The use of CSA significantly enhanced the compressive strength development and dimensional stability of the mortar. This improvement was associated with a reduction in the porosity, which was attributed to ettringite formation. Furthermore, while the SRA slightly reduced the compressive strength, it significantly improved the dimensional stability.

CivilEng doi: 10.3390/civileng7010015

Authors: Bassel Bakleh George Wardeh Hala Hasan Ali Jahami Antonio Formisano

The long-term behavior of reinforced concrete (RC) structures under sustained loading is strongly affected by creep and cracking, particularly under service conditions where tension stiffening and curvature changes are significant. This study investigates the flexural response of cracked RC beams through combined numerical and experimental analyses. A new 1D finite element model is proposed, integrating nonlinear material behavior, damage mechanics, and time-dependent effects, including creep in both compression and tension. The model relies on a layered fiber section approach and uses a Newton–Raphson iterative procedure to solve equilibrium, allowing accurate prediction of strain, curvature, and internal force evolution over time. The model shows excellent agreement with experimental observations and ABAQUS simulations, accurately capturing deflection trends and crack development. Its performance is further validated using a database of 55 RC beams, including specimens with recycled aggregates and fiber reinforcement. Across this dataset, 84.5% of predicted deflections fall within ±1 mm of measured values, with an R2 of 0.960, demonstrating strong reliability. A Sobol-based sensitivity analysis identifies load ratio as the most influential parameter on long-term deflection, followed by concrete strength and humidity. Overall, the model offers an efficient and robust tool for long-term deflection prediction, bridging simplified design rules and complex 3D simulations.

CivilEng doi: 10.3390/civileng7010014

Authors: Mona Rais Esmaili Anjan K. Bhowmick

Nonlinear seismic analysis procedures can accurately estimate structural responses but are computationally intensive, making them impractical for engineering design. This study provides the first comprehensive evaluation of N2 and modal pushover analysis for eccentrically braced frames (EBFs), revealing their strengths and limitations in predicting link rotations, shear demands, and drift distribution under Canadian seismic hazards. Analyzed were four-, eight-, and 14-storey chevron EBFs under real and artificial ground motions compatible with the response spectrum of Vancouver, Canada. The findings indicate that inelastic link rotations for all EBFs remain below the design limit of 0.08 rad, except for the upper two floors of the 14-storey EBFs. Seismic analysis reveals that maximum inelastic link shear forces often exceed design recommendations. It is also observed that both the N2 method and MPA procedure could reasonably predict the peak roof displacements for low-rise EBF buildings. In addition, while the MPA procedure provides better predictions of maximum inter-storey drifts over all storeys for medium-to-taller EBFs, inter-storey drifts are not predicted well in the N2 method. Additionally, the current code formula for estimating the fundamental period of EBFs predicts shorter periods than those obtained from analysis. An improved formula for estimating EBF periods is proposed.

CivilEng doi: 10.3390/civileng7010013

Authors: Lanying Xie Haifan Wang Ningbo Wang Cheng Zhang Xiangguo Li Yang Lv Bo Tian

Concrete, as a widely used construction material, suffers from performance degradation due to chloride penetration and sulfate attack in harsh environments. Conventional performance-enhancing methods are costly and emit high levels of carbon dioxide. This study modified graphene oxide (GO) with polycarboxylate superplasticizer (PCE) alone or PCE synergized with a rubber viscosity reducer, optimized dispersion (50 °C water bath for 1 h), and prepared C50 modified concrete (500 kg/m3 cementitious materials, w/b = 0.33). GO contents were 0%, 0.001%, 0.003%, 0.005%; a group with 8% reduced cementitious materials (460 kg/m3) was also tested. Results showed PCE-viscosity reducer synergy better dispersed GO, improving concrete workability. GO accelerated cement hydration via nucleation, refining C-S-H gel and reducing porosity. At 0.005% GO, 56 d drying shrinkage dropped by 29.3% vs. the blank, and 56 d chloride penetration electric flux was 586 C, meeting 100-year service life. Sulfate resistance also improved with higher GO content. Even with 8% less cementitious materials, modified concrete outperformed the blank. This provides support for GO’s application in cement-based materials.

CivilEng doi: 10.3390/civileng7010012

Authors: Baraa A. Alfasi Ata M. Khan

Avoiding highway infrastructure construction cost overruns and reducing associated claims and disputes continues to be a challenge in many countries. Research is needed in identifying notable project planning and management deficiencies that are likely to cause cost overruns. The literature suggests numerous potential causes of cost overrun but the clustering of cause variables and relative importance of clusters has not been researched. The research reported here addresses this knowledge gap using predictive models developed with data contributed by several agencies in participating countries and suggests mitigation measures. Following a review of methods and data sources, a methodological framework is advanced that encompasses statistical methods well suited for providing a scientific basis for identifying important clusters of cost overrun variables. Fifty-three completed questionnaires contributed by knowledge experts and experienced managers from Canada, the United States, the Middle East, and Australia met the sample requirements of statistical methods. Starting from 53 variables, the principal component-supported factor analysis method identified clusters of cost overrun variables and their relative importance was inferred with developed logistic regression models. Deeper insights into the causes of cost overruns obtained from this research suggest mitigation measures (e.g., improved qualification and experience of personnel, enhanced planning and design practices, risk analysis of inputs to cost estimation process) that are within reach of managers. The results can enhance infrastructure planning and management practice including a reduction in claims and disputes.

CivilEng doi: 10.3390/civileng7010011

Authors: Ajanta Kalita Nisha Kumari Singh Ghritartha Goswami Sudip Basack Moses Karakouzian

The demand for sustainable and environmentally friendly soil stabilization methods for subgrade improvement for pavements has led to exploring techniques that minimize ecological impact while optimizing engineering properties. Traditional stabilizers like cement and lime, though effective, have significant environmental drawbacks, including a high carbon footprint, disruption of vegetation, and health risks to workers. This study investigates the efficiency of biopolymers and eggshell powder as eco-friendly, sustainable soil stabilization agents. Parameters such as compaction characteristics, California Bearing Ratio (CBR), and micro-structural analysis were assessed. The research evaluates soil samples treated with varying concentrations of biopolymer (1%, 2%, and 3%) and eggshell powder (4%, 6%, and 8%). Results indicated that biopolymer addition slightly decreased the maximum dry density (MDD) and increased the optimum moisture content (OMC), while eggshell powder slightly increased MDD and decreased OMC. The optimal mix, soil + 1% xantham gum + 6% eggshell powder, enhanced CBR by 225.6% and 323.8% for soaked and unsoaked conditions, respectively. The scanning electron microscope revealed that treated soil samples transformed into a hard solid matrix, demonstrating improved stability. EDX analysis revealed the mineralogical composition of the mixes. Overall, the use of biopolymers and eggshell powder not only enhances soil strength but also promotes environmental sustainability.

CivilEng doi: 10.3390/civileng7010010

Authors: Shimaa Emad Alaa Elsisi Eman Sharaf Atef Eraky Abdallah Salama

The accurate estimation of the fundamental period is critical for seismic design using the Equivalent Lateral Force method. This study evaluates widely used empirical period formulae from international seismic codes and previous research by comparing them with detailed finite element method (FEM) analyses. A total of 93 reinforced concrete building models were assessed. The results show that most empirical formulae, notably the American Society of Civil Engineers Standard (ASCE 7-10), the Eurocode, the National Building Code of Canada (NBCC), and the Saudi Building Code (SBC 301), systematically underestimate the fundamental period in low- and mid-rise buildings often by more than 40% under cracked conditions, while discrepancies reduce under uncracked assumptions. Equations such as those proposed by the Building Standard Law of Japan (BSLJ) and Australian Standard (AS 11407.2) show comparatively closer agreements with FEM predictions, whereas formulae developed by Goel and Chopra and by Alguhane et al. have distinct differences, especially at greater heights. Statistical parameters, including the arithmetic mean difference and the standard deviation, were employed to enhance the comparison and assess the accuracy and dispersion of the estimated fundamental periods. The results indicate that empirical formulae, although beneficial in first-design stages, are likely to yield conservative results and suggest the use of advanced numerical computation or revised models and coefficients for RC high-rise and irregular buildings.

CivilEng doi: 10.3390/civileng7010009

Authors: P. D. P. O. Peramuna Srikanth Venkatesan N. G. P. B. Neluwala K. K. Wijesundara Saman De Silva

Cascade dams describe an arrangement of several dam structures built along a flow path. Failure of one upstream dam in the cascade system can trigger catastrophic consequences to the downstream dams, as evidenced recently in the Edenville Dam and Sanford Dam. Previous research has mainly focused on rainfall-induced dam failures, although recent failures have demonstrated a combination of floods and earthquakes. Moreover, limited studies have analyzed the sensitivity of dam breach parameters, such as dam breach height and width in dams arranged in a cascade system for seismic events. Most hydraulic simulations that model seismic-induced dam failures assume the complete collapse of dams to analyze the downstream consequences. Hence, this study presents a novel analysis in simulating earthquake-induced failures in a cascade dam system, considering the sensitivity of dam breach parameters. In addition, dam breach parameters have been derived from the structural analysis of dams employing Finite Element Models (FEMs) to a critical Peak Ground Acceleration (PGA) of 0.3 g. Two-dimensional hydrodynamic simulations, along with the full dynamic wave equations, are undertaken in the study to model the earthquake-induced cascade dam failures. The results further elaborate on the significance of modeling cascade dam failures in terms of the consecutive arrival of floods and total flow compared to individual dam failures. Sensitivity analysis of dam breach parameters shows that the breach height is more significant than the breach width and breach slope. However, its significance decreases as the dam breach flood flow path increases in distance. The study further confirms the novel utilization of structural analysis to derive dam breach parameters for seismic-induced dam failures of concrete arch dams and rockfill dams, which will guide the optimization of disaster mitigation strategies and the operational resilience of the dams.

CivilEng doi: 10.3390/civileng7010008

Authors: Tânia Feiri Til Lux Udo Wiens Marcus Ricker

Annex A of EN 1992-1-1:2023—recently revised and amended in the context of the Second Generation of Eurocodes—introduces a method to adjust partial safety factors for the resistance side alongside a set of factors for different conditions and design situations, both for new and existing structures. The method proposed in Annex A is complemented by a set of stochastic models for relevant basic variables and forms a rather simple and objective format to adjust the partial safety factors from the default values offered in EN 1990:2023. Yet, over the last few years, advanced reliability-based methods aligned with modern computational tools have proved to enable rather robust and efficient structural reliability assessments. A thorough comparative analysis is imperative to understand how distinct reliability-based methods can be applied to adjust partial safety factors in the design of new structural components composed of steel-reinforced concrete. This analysis sheds light on the use of different methods to derive partial safety factors for the resolution of common engineering problems and offers inferences regarding possible implications in terms of safety and economic efficiency of design solutions.

CivilEng doi: 10.3390/civileng7010007

Authors: Gaurav Chobe Ishaan Davariya Dheeraj Waghmare Shivam Sharma Akanshu Sharma Amit H. Varma Vilas G. Pol

Lithium-ion batteries (LIBs) are essential for electric vehicles, consumer electronics, and grid storage, but their rapidly increasing demand is paralleled by growing waste volumes. Current disposal methods remain costly, complex, energy-intensive, and environmentally unsustainable. This pilot study investigates a scalable, low-impact disposal method by incorporating LIB waste into concrete, evaluating both the structural and environmental effects of LIB waste on concrete performance. Several cement–mortar cube specimens were cast and tested under compression using the cement–mortar mix with varying battery waste components, such as black mass and varied metals. All mortar mixes maintained an identical water-to-cement ratio. The compressive strength of the cubes was measured at 3, 7, 14, 21, and 28 days after casting and compared. The mix containing black mass exhibited a 35% reduction in compressive strength on day 28, whereas the mix containing varied metals showed a 55% reduction relative to the control mix without LIB waste. A case study was conducted to evaluate the combined structural and environmental performance of a concrete specimen incorporating LIB waste by estimating the embodied carbon (EC) for each mix and comparing the strength-to-net EC ratio. Selective incorporation of LIB waste into concrete provides a practical, low-carbon upcycling pathway, reducing both embodied carbon and landfill burden while enabling greener, non-structural construction materials. This sustainable approach simultaneously mitigates battery waste and lowers cement-related CO2 emissions, delivering usable concrete for non-structural and low-strength structural applications.

CivilEng doi: 10.3390/civileng7010006

Authors: Navid Bohlooli Hadi Bahadori Hamid Alielahi Daniel Dias Mohammad Vasef

Construction on soft, highly compressible soils increasingly requires reliable ground improvement solutions. Among these, Rigid Inclusions (RIs) have emerged as one of the most efficient soil-reinforcement techniques. This paper synthesizes evidence from over 180 studies to provide a comprehensive state-of-the-art review of RI technology encompassing its governing mechanisms, design methodologies, and field performance. While the static behavior of RI systems has now been extensively studied and is supported by international design guidelines, the response under cyclic and seismic loading, particularly in liquefiable soils, remains less documented and subject to significant uncertainty. This review critically analyzes the degradation of key load-transfer mechanisms including soil arching, membrane tension, and interface shear transfer under repeated loading conditions. It further emphasizes the distinct role of RIs in liquefiable soils, where mitigation relies primarily on reinforcement and confinement rather than on drainage-driven mechanisms typical of granular columns. The evolution of design practice is traced from analytical formulations validated under static conditions toward advanced numerical and physical modeling frameworks suitable for dynamic loading. The lack of validated seismic design guidelines is high-lighted, and critical knowledge gaps are identified, underscoring the need for advanced numerical simulations and large-scale physical testing to support the future development of performance-based seismic design (PBSD) approaches for RI-improved ground.

CivilEng doi: 10.3390/civileng7010005

Authors: Tareq Salloum Ernest Forman

This paper presents a quantitative framework for assessing and managing public-safety risks around dams. The framework integrates a hazard–event–objective–control structure with the Analytic Hierarchy Process (AHP) to transform qualitative judgments into quantitative risk measures. Likelihoods, consequences, and overall risk are expressed on a ratio scale, allowing results to be aggregated, compared, and communicated in monetary terms. Probabilistic simulation accounts for uncertainty and generates outputs such as Value-at-Risk (VaR), loss-exceedance curves, and societal F–N charts, providing a clear picture of both expected and extreme outcomes. Optimization identifies control portfolios that achieve the greatest risk reduction for available budgets. A hypothetical dam case study demonstrates the framework’s application and highlights its ability to identify high-value safety investments. The framework offers dam owners and regulators a transparent, data-driven basis for prioritizing public-safety improvements and supports both facility-level (micro) and program-level (macro) decision-making consistent with international risk-tolerability and ALARP principles.

CivilEng doi: 10.3390/civileng7010004

Authors: Mohamed Algamati Abobakr Al-Sakkaf Ashutosh Bagchi

Base isolation is known as a useful and popular technique for seismic upgrading of reinforced concrete buildings. Predicting damage levels based on relative inter-story drift plays an important role for designing optimal base isolation systems. However, the existing codes usually rely on the acceleration spectrum for calculating the relative inter-story drift, and they do not provide an accurate estimation of the relative inter-story drift. Consequently, to cover the research gap, machine learning algorithms are being trained and used for identification of damage levels in retrofitted reinforced concrete buildings. More than 7000 datasets were derived by using nonlinear time-history and incremental dynamic analysis. A total of 48 reinforced concrete buildings with different stories and bay numbers were designed based on an older version of existing building codes, and then, base isolation systems were designed for the seismic retrofit. The machine learning algorithms used here were Decision Tree, Random Forest, Support Vector Machine, Extreme Gradient Boosting, and an Artificial Neural Network. Based on the results, four of the mentioned algorithms have the capability of predicting the damage level with an accuracy of more than 85%, with the best performance being reached by extreme gradient boosting with an accuracy of 89%. Finally, the most important parameters affecting the damage levels of retrofitted reinforced concrete buildings were derived.

CivilEng doi: 10.3390/civileng7010003

Authors: Hamed Abdul Baseer G. G. Md. Nawaz Ali

The construction industry significantly contributes to global sustainability challenges, producing 30–40 percent of global carbon dioxide emissions and consuming large amounts of natural resources. Pervious concrete has emerged as a sustainable alternative to conventional pavements due to its ability to promote stormwater infiltration and groundwater recharge. However, the absence of fine aggregates creates a highly porous structure that results in reduced compressive strength, limiting its broader structural use. Determining compressive strength traditionally requires destructive laboratory testing of concrete specimens, which demands considerable material, energy, and curing time, often up to 28 days—before results can be obtained. This makes iterative mix design and optimization both slow and resource intensive. To address this practical limitation, this study applies Machine Learning (ML) as a rapid, preliminary estimation tool capable of providing early predictions of compressive strength based on mix composition and curing parameters. Rather than replacing laboratory testing, the developed ML models serve as supportive decision-making tools, enabling engineers to assess potential strength outcomes before casting and curing physical specimens. This can reduce the number of trial batches produced, lower material consumption, and minimize the environmental footprint associated with repeated destructive testing. Multiple ML algorithms were trained and evaluated using data from existing literature and validated through laboratory testing. The results indicate that ML can provide reliable preliminary strength estimates, offering a faster and more resource-efficient approach to guiding mix design adjustments. By reducing the reliance on repeated 28-day test cycles, the integration of ML into previous concrete research supports more sustainable, cost-effective, and time-efficient material development practices.

CivilEng doi: 10.3390/civileng7010002

Authors: Cristian Georgeoi Ioan Petran Camelia Maria Negrutiu Pavel Ioan Sosa

This study examines the use of electronic waste (e-waste) as an alternative material in concrete for sustainability and natural resource conservation. Various e-wastes, such as Polyvinyl Chloride (PVC), Glass-Reinforced Plastic (GRP), Glass Fiber-Reinforced Polymer (GFRP), cross-linked polyethylene (XLPE), polyethylene (PE), electronic cable waste (ECW), Waste Electrical Cable Rubber (WECR), copper fiber (Cu Fib.), aluminum Fibers (Al fib.), steel fibers, basalt fibers, glass fibers, aramid−carbon fibers, Kevlar fibers, jute fibers, and optical fibers, were tested for influence on compressive, flexural, tensile strength, modulus of elasticity, and water absorption. Outcomes show that fine particle waste at low levels (0.2–1.5%) can improve mechanical performance, while higher levels of replacement or coarse particles generally reduce performance. Mechanical and physical properties are highly sensitive to material type, particle size, and dose. Life cycle assessment (LCA) and predictive modeling are recommended as validation for sustainability benefits.

CivilEng doi: 10.3390/civileng7010001

Authors: Ghazi Jalal Kashesh Hasan H. Joni Anmar Dulaimi Abbas Jalal Kaishesh Adnan Adhab K. Al-Saeedi Tiago Pinto Ribeiro Luís Filipe Almeida Bernardo

The growing demand for sustainable pavement materials has driven increased interest in asphalt mixtures incorporating recycled crumb rubber (CR). While CR modification enhances mechanical performance and durability, its often increases initial production costs and energy demand. This study develops an integrated framework that combines machine learning (ML) and economic analysis to identify the optimal balance between performance and cost in CR-modified asphalt overlay mixtures. An experimental dataset of conventional and CR-modified mixtures was used to train and validate multiple ML algorithms, including Random Forest (RF), Gradient Boosting (GB), Artificial Neural Networks (ANNs), and Support Vector Regression (SVR). The RF and ANN models exhibited superior predictive accuracy (R2 > 0.98) for key performance indicators such as Marshall stability, tensile strength ratio, rutting resistance, and resilient modulus. A Cost–Performance Index (CPI) integrating life-cycle cost analysis was developed to quantify trade-offs between performance and economic efficiency. Environmental life-cycle assessment indicated net greenhouse gas reductions of approximately 96 kg CO2-eq per ton of mixture despite higher production-phase emissions. Optimization results indicated that a CR content of approximately 15% and an asphalt binder content of 4.8–5.0% achieve the best performance–cost balance. The study demonstrates that ML-driven optimization provides a powerful, data-based approach for guiding sustainable pavement design and promoting the circular economy in road construction.

CivilEng doi: 10.3390/civileng6040069

Authors: Onur Gurler Ozgur Ozcelik Sadik Can Girgin Atakan Aksoy Cagri Cetik

Energy-dissipating braces are novel structural components as they not only accommodate the seismic energy demand but also enhance both the flexibility and overall earthquake resistance of the structure, preventing brittle or non-ductile behavior. The novel brace proposed in this study was developed to achieve two primary objectives: first, to restrict relative displacements at its ends by dissipating energy through U-shaped flexural plates (UFPs), and second, to provide a self-centering mechanism through the use of post-tension (PT) to ensure structural re-centering after cyclic loading. The novelty of this research lies in the experimental findings showing that post-tensioned (PT) braces exhibit a flag-shaped self-centering hysteretic response, improved initial stiffness, and reduced residual displacements by 72%, while non-PT braces behave as conventional metallic dissipators with larger residual displacements. Increasing UFP thickness from 6 to 8 mm enhances strength by 22%. Stainless steel UFPs offer superior plastic recovery, whereas regular steel UFPs dissipate ~%10 more energy through greater plasticity. Energy dissipation of the brace increases with increasing PT forces and displacement due to the PT force pulling the force–displacement curve towards high force levels. This study highlights the importance of PT force and UFP parameters in a brace configuration with self-centering and metallic dissipators such as U-shaped flexural plates.

CivilEng doi: 10.3390/civileng6040068

Authors: Mohamed Gindy Moutaman M. Abbas Radu Muntean Silviu Butnariu

The cement industry significantly contributes to global CO2 emissions, making material efficiency in concrete structures a crucial sustainability goal. This study addresses the challenge of excessive cement usage in traditional concrete design by optimizing a cast-in-place concrete bench. A density-based topology optimization framework was implemented in ANSYS Mechanical and enhanced with a deep-learning surrogate model to accelerate computational performance. The optimization aimed to minimize the structural mass while satisfying serviceability and strength constraints, including limits on displacement and compressive stress under realistic public-use loading conditions. The topology optimization converged after 62 iterations, achieving a 46% reduction in mass (from 258.3 kg to 139.4 kg) while maintaining a maximum deflection below 2 mm and a maximum compressive stress of 15.5 MPa, within the allowable limit for C20/25 concrete. The deep-learning surrogate model achieved strong predictive accuracy (IoU = 0.75, Dice = 0.73) and reduced computation time by over 105× compared to the full finite element optimization. The optimized geometry was reconstructed and rendered using Blender for visualization. These results highlight the potential of combining topology optimization and machine learning to reduce material use, enhance structural efficiency, and support sustainable practices in concrete construction.

CivilEng doi: 10.3390/civileng6040067

Authors: Mohammad Amin Oyarhossein Gabriel Sugiyama Fernanda Rodrigues Hugo Rodrigues

This article presented a method for grading and visualising corrosion in steel pedestrian bridges using Building Information Modelling (BIM). Traditional inspection methods are often manual and subjective, which reduces their reliability and repeatability. To enhance the recording and reporting of inspection results, a five-level corrosion severity grading system was developed using matched photographic data from two inspection campaigns conducted in February 2024 and April 2025. The grades were assigned based on visual signs, including surface rust, coating damage, and flaking. A Dynamo script was used to link each grade to the corresponding elements in a Revit model using colour overrides. The proposed approach enables corrosion data to be integrated into the BIM environment in a clear, structured manner. This helps engineers assess the structure’s condition, monitor changes over time, and make informed maintenance decisions. The workflow was demonstrated using case studies from a steel pedestrian bridge in Aveiro, Portugal. The method is adaptable for future digital twin applications and supports the development of BIM-based tools for bridge asset management. The workflow was applied to over 2600 elements, with 75 visually degraded cases identified and classified into five grades, demonstrating the method’s feasibility for systematic corrosion tracking. The proposed workflow was tested on a coastal steel bridge and could be generalised to other bridges with similar environmental conditions.

CivilEng doi: 10.3390/civileng6040066

Authors: Fahmidah Ummul Ashraf William H. Pennock Ashish D. Borgaonkar

Given the apparent gap between scientific research and engineering practice, this paper tracks the dominating perspectives that have shaped the growth of hydrological research. Based on five eras, dominated with specific paradigms and/or ideologies, this paper highlights the punctuated growth of flood frequency analysis comparative to the enormous progress made in hydrological modeling can be claimed by the 20th century. The historical narrative underpinning this inquiry indicates that progress in hydrological understanding can be characterized by two contrasting claims: modeling breakthroughs and inconclusive results. Contradicting statistical assumptions, complex modeling structures, the standardization of specific techniques, and the absence of any unified physical meaning of the research results brought an apparent conflict between the scope of hydrologic research and the scope of end users, i.e., civil engineers. Some hydrologists argue that the debates associated with hydrologic progress, i.e., the evolution of statistical methods, dating back to the 1960s remain unaddressed, with each era introducing additional uncertainty, questions, and concerns. Progress, for it to happen, needs synthesis among scientists, engineers, and stakeholders. This paper concludes that, in a similar way to how physicists acknowledge the conflicts between quantum and Newtonian physics, hydrology too can benefit from acknowledging divergent principles emerging from engineering practice. While many advanced analytical tools—though varied in form—are grounded in the assumption that past data can predict future conditions, the contrasting view that past data cannot always do so represents a key philosophical foundation for resilience-based civil engineering design. Acknowledging contrasting philosophies describing the nature of reality can help illuminate the conundrum in the scope of hydrological research and can enable synthesis activities aimed at ‘putting the puzzle together’.

CivilEng doi: 10.3390/civileng6040064

Authors: Aaron Gutierrez-Lopez Dante Tolentino Federico Valenzuela-Beltran J. Martin Leal-Graciano Juan Bojorquez J. Ramon Gaxiola-Camacho

The structural performance of mid-rise buildings with a soft first story is a critical issue in earthquake-prone regions. This paper presents a detailed assessment of both the seismic performance and the structural reliability of a confined masonry mid-rise building with a soft reinforced-concrete first-story irregularity located in Mexico. This structure was designed according to outdated building codes to reflect construction practices that remain common in some parts of the country. Nonlinear dynamic analyses were conducted using ETABS v21. To simulate various seismic scenarios, ground motion records associated with return periods of 72, 475, and 975 years, respectively, were implemented. The results demonstrated that maximum inter-story drift is predominantly concentrated at the first story, exceeding the performance thresholds for immediate occupancy, life safety, and collapse prevention. Furthermore, a probabilistic performance assessment was developed considering the randomness of inter-story drift responses. Then, reliability index (β) was calculated for each seismic scenario. In all cases, β values remained consistently below the minimum recommended limit. These findings confirm the formation of a soft-story mechanism at the first level and are relevant for buildings designed under construction provisions like those used in the present case study.

CivilEng doi: 10.3390/civileng6040065

Authors: Muhammad Usama Aslam Tariq Umar Musaab Suliman Muhammad Usman Siddiq Hamid Rajabnejad Ambar Farooq

The increasing integration of Chinese-engineered infrastructure in Pakistan under the China–Pakistan Economic Corridor (CPEC) necessitates a comparative evaluation of seismic resilience between the Chinese and Pakistani building codes. This study focused on the seismic performance of reinforced concrete (RC) frames designed according to these two codes. Fragility curves were generated for 4-story, 8-story, and 12-story buildings subjected to varying seismic intensities using Incremental Dynamic Analysis (IDA). The results indicate that structures designed under the Chinese code exhibit up to 12% lower fragility values, suggesting enhanced seismic resilience, particularly at higher seismic intensities. Additionally, the study investigates the effectiveness of Lead Rubber Bearings (LRBs) for seismic isolation, demonstrating that their integration improves the seismic performance of RC frames by enhancing energy dissipation and reducing the likelihood of exceeding various damage states by up to 25%. These findings underscore the importance of adopting stringent seismic design provisions, such as those found in the Chinese code, to enhance the resilience and safety of infrastructure, especially in seismic-prone regions.

CivilEng doi: 10.3390/civileng6040063

Authors: Cheng Peng Yang Wang Bo Deng Dongxing Wang

This study presents an environmentally friendly alternative to conventional energy-intensive methods for soil improvement by investigating an enzyme-induced active magnesium oxide carbonation (EIMC) technique for the stabilization of gravelly soil. The solidification efficacy and strengthening mechanism of EIMC-treated soil were systematically investigated through a combination of mechanical property tests and microstructural analyses. Results indicate that key mechanical properties—including compressive strength, shear strength, and elastic modulus—were directly proportional to the magnesium oxide (MgO) content. Notably, an 8% MgO content resulted in a 113-fold increase in unconfined compressive strength (UCS) compared to the untreated soil. The strength development stabilized after a five-day curing period. While higher MgO content yielded greater absolute strength, the efficiency of strength gain per unit of MgO peaked at a 4% dosage. Consequently, considering both performance and efficiency, an MgO content of 4% and a curing period of 5 days are recommended as the optimal parameters. The EIMC treatment substantially improved the soil’s mechanical properties, inducing a transition in the failure mode from plastic to brittle, with this brittleness becoming more pronounced at higher MgO concentrations. Furthermore, the treatment enhanced the soil’s water stability. Microstructural analysis revealed that the formation of hydrated magnesium carbonates filled voids, cemented particles, and created a dense structural matrix. This densification of the internal structure underpinned the observed mechanical improvements. These findings validate EIMC as a feasible and effective eco-friendly technique for gravelly soil stabilization.

CivilEng doi: 10.3390/civileng6040062

Authors: Sakdirat Kaewunruen Charalampos Baniotopoulos Patrick Teuffel Hamza Driou Otso Valta Jan Pešta Diana Bajare

It is undeniable that digital technology enables, e.g., building information modelling, digital twins, extended reality (i.e., virtual reality, augmented reality, mixed reality), and automation, have recently played a significant role in the construction and engineering industry. The traditional applications of digital technologies include design and construction management, waste management, and, to a limited extent, asset management. Despite some applications of digital technologies, the technology users are often isolated and siloed. In reality, the cross-functional applications, roles, and co-benefits have not been thoroughly understood or well demonstrated. This is evident by a very limited usage of such technology across either the whole lifecycle or the value chain of built environment sectors. On this ground, this study is the first to tackle the challenges by conducting expert and stakeholder interviews using open-ended questionnaires both online and offline (n = 42) to identify synergic roles and influences, as well as co-benefits of digital technology enablers. Industry participants are dominant in our study and, unsurprisingly, siloed practice can undermine cross-collaboration among value chain stakeholders. Clearly, co-benefits may hypothetically occur, but they can be only unlocked by genuine, participative stakeholder engagement. This study is unprecedented, and our new findings also reveal technical and societal capabilities of digital technologies, which can inclusively enable participative decision-making, engagement, and integration of stakeholders for implementing buildings’ circularity through viable business and management models. New insights clearly exhibit that digital technology enablers must be co-created by main stakeholders in order to yield co-benefits and harvest synergic value for circular management models in the built environment.

CivilEng doi: 10.3390/civileng6040061

Authors: Felix Weber

This paper analyzes the physics of the TMD-Inerter for harmonic vibrations. The basic TMD-Inerter layout is assumed, where the inerter is installed between the TMD mass and the structural mass. For harmonic vibrations, the inerter force can be formulated as a function of terminal displacements. This formulation demonstrates that the inerter force is, in fact, a negative stiffness force with frequency-dependent negative stiffness coefficient. Based on this finding, the optimal stiffness tuning of the TMD-Inerter is derived. As this stiffness tuning can only be realized by a controlled actuator, the tuning of the spring of the TMD-Inerter is presented. As this spring is a passive element, its optimum tuning must be made at a selected frequency of vibration. It is shown that the average of the TMD natural frequency and structural eigenfrequency leads to a close to optimal spring tuning. This approach needs to be combined with increased damping of the TMD-Inerter to minimize the structural displacement response. Despite the close to optimal tunings of stiffness and damping, the resulting primary structure displacement response is approximately 41.6% greater than that due to the classical TMD. The reason for this lies in the fact that the passive spring of the TMD-Inerter cannot compensate for the frequency-dependent negative stiffness of the inerter within the entire frequency range.

CivilEng doi: 10.3390/civileng6040060

Authors: Andreas Ratka Wolfgang Ernst Matthias Wörlein

Within the scope of this article is the presentation of a modelling and measurement approach for the effects of roof greenings and the application of the approach to evaluate the influence of roof greenings upon the thermal conditions inside a typical residential building. It is shown that overheating in summer can be reduced, and thermal comfort for inhabitants can be increased. The cooling is caused by the transpiration of plants and by the evaporation of water from the substrate. Other relevant physical effects are the shading of plants and the increase in the heat capacity of the building. In state-of-the-art buildings, a layer with a high insulating effect is incorporated into the envelope. This leads to the effect that a huge fraction of the cooling power is taken from the outside of the building and only a smaller part is taken from the inside. In order to mitigate this decoupling, a hydraulic connection between the greening and the interior of the building is introduced. To evaluate the effect of the inside cooling, the difference in the number of yearly hours with overheating in residential buildings is estimated. In addition, the reduction in energy demand for the climatisation of a typical residential building is calculated. The used methods are as follows: (1) Performance of laboratory and free field measurements. (2) Simulation of a typical residential building, using a validated approach. In summary, it can be said that green roofs, in particular with hydraulic connections, can significantly increase the interior thermal comfort and potentially reduce the energy required for air conditioning.

CivilEng doi: 10.3390/civileng6040059

Authors: Maximilian Gehring Jascha Brötzmann Uwe Rüppel

Traditional construction logistics rely on manual processes and fragmented tools, leading to inefficient planning, poor communication, and disorganized supply chains. Despite advances in digitalization, there is a lack of integrated, data-driven approaches tailored to construction logistics. To address this gap, this paper adopts a design-science approach to develop and evaluate a modular Digital Twin (DT) framework, the ConLogTwin. The framework integrates planning data with real-time site data through a robust data storage layer and digital services for automated planning and analytics. A prototype demonstrates the technical feasibility of mirroring both physical and organizational setups of projects, enabling more efficient and adaptive logistics management. The work contributes a modular reference architecture that integrates established open-source tools into a coherent, adaptable framework for construction logistics, enhancing practical applicability and lowering implementation barriers. A limitation is that the framework has not yet been validated in a full-scale field study, leaving its effectiveness in practice to be tested in a future study.

CivilEng doi: 10.3390/civileng6040058

Authors: Mu’tasim Abdel-Jaber Rawand Al-Nsour Ahmed Ashteyat

The incorporation of Basalt Fiber-Reinforced Polymer (BFRP) materials marks a significant advancement in the adoption of sustainable and high-performance technologies in structural engineering. This study investigates the flexural behavior of four-meter, two-span continuous reinforced concrete (RC) beams of low and medium compressive strengths (20 MPa and 32 MPa) strengthened or rehabilitated using near-surface mounted (NSM) BFRP ropes. Six RC beam specimens were tested, of which two were strengthened before loading and two were rehabilitated after being preloaded to 70% of their ultimate capacity. The experimental program was complemented by Finite Element Modeling (FEM) and analytical evaluations per ACI 440.2R-08 guidelines. The results demonstrated that NSM-BFRP rope application led to a flexural strength increase ranging from 18% to 44% ductility by approximately 9–11% in strengthened beams and 13–20% in rehabilitated beams, relative to the control specimens. Load-deflection responses showed close alignment between experimental and FEM results, with prediction errors ranging from 0.125% to 7.3%. This study uniquely contributes to the literature by evaluating both strengthening and post-damage rehabilitation of continuous RC beams using NSM-BFRP ropes, a novel and eco-efficient retrofitting technique with proven performance in enhancing structural capacity and serviceability.

CivilEng doi: 10.3390/civileng6040057

Authors: Raid S. Alrashidi Megan S. Voss Ali Alsubeai Emad Alshammari Kyle A. Riding

UHPC has been found to have excellent freeze–thaw durability in cold regions. Previous UHPC testing performed has mostly focused on concrete with compressive strength above 21 ksi (145 MPa). In this study, testing was conducted to determine at what strength level concrete transitions to provide excellent freeze–thaw (F–T) performance. Non-proprietary concrete samples were made for freeze–thaw durability from four different concrete mixture designs: 12–15 ksi, 15–18 ksi, 18–21 ksi, and 21+ ksi (83–145+ MPa), and these were tested according to ASTM C666, using 1.5% steel fibers. The samples were made for three different curing regimens: limewater curing in a fog room, simulated precast curing, and steam curing. Low-temperature differential scanning calorimetry (DSC) and mercury intrusion porosimetry (MIP) tests were carried out to reveal the freeze–thaw mechanism of the concrete samples. All mixtures with compressive strength above 15 ksi (103 MPa) performed excellent in freeze–thaw testing with no damage seen. Steam curing was found to negatively affect the freeze–thaw performance at the lowest strength level tested.

CivilEng doi: 10.3390/civileng6040056

Authors: Yanuar Haryanto Gathot Heri Sudibyo Hsuan-Teh Hu Fu-Pei Hsiao Laurencius Nugroho Dani Nugroho Saputro Habib Raihan Suryanto Abel Earnesta Christopher Haryanto

This study presented a comprehensive finite element (FE) investigation into the flexural behavior of RC T-beams strengthened in the negative moment region using near-surface mounted (NSM) carbon-fiber-reinforced polymers (CFRP) rods. A three-dimensional nonlinear FE model was developed and validated against experimental data, achieving close agreement with normalized mean square error values as low as 0.006 and experimental-to-numerical ratios ranging from 0.95 to 1.04. The validated model was then employed to conduct a systematic parametric analysis considering CFRP rod diameter, concrete compressive strength, longitudinal reinforcement ratio, and FRP material type. The results showed that increasing CFRP diameter from 6 to 10 mm enhanced ultimate load by up to 47.51% and improved stiffness by 1.48 times. Higher concrete compressive strength contributed to stiffness gains exceeding 50.00%, although this improvement was accompanied by reductions in ductility. Beams with reinforcement ratios up to 2.90% achieved peak loads of 309.61 kN, but ductility declined. Comparison among FRP materials indicated that CFRP and AFRP offered superior strength and stiffness, whereas BFRP provided a more balanced combination of strength and deformation capacity.

CivilEng doi: 10.3390/civileng6040055

Authors: Nguyen Quoc Bang Dinh Van Duy Tran Van Ty Cu Ngoc Thang Nigel K. Downes Hitoshi Tanaka

Riverbank erosion in the Vietnamese Mekong Delta (VMD) poses a serious threat to agricultural lands, infrastructure, and local communities. Conventional protective measures, such as synthetic geotextiles and concrete revetments, are often costly and environmentally disruptive. This study investigates the potential of Eichhornia crassipes, a widely available invasive species, commonly known as water hyacinth (WH), to produce biodegradable geotextiles as a low-cost, nature-based solution (NbS) for small-scale riverbank protection. It is the first to test minimally processed WH mats under simulated tidal conditions in the VMD. Laboratory experiments were conducted to evaluate the geotextile’s (1) sediment retention capacity, (2) wave energy reduction, and (3) mechanical durability under wet–dry cycles. Results show that the WH geotextile effectively reduced sediment resuspension, decreasing turbidity levels from 800 FTU (unprotected scenario) to below 50 FTU. The geotextile also attenuated wave energy, reducing significant wave heights by approximately 35–40%. Mechanical testing revealed that the fish bone weaving pattern with adhesive coating achieved the highest tensile strength (8.36 kN/m after 12 wet–dry cycles), while uncoated samples demonstrated higher elongation (up to 61.67%), providing greater flexibility. These demonstrate the feasibility of WH geotextiles as a scalable nature-based solution for erosion-prone tropical deltas. Future studies should focus on field-scale validation, biodegradation rates, and performance optimization for long-term applications.

CivilEng doi: 10.3390/civileng6040054

Authors: Peng Gao Yongjin Cheng Bin Wang Zhenqiang Jiang Ben He Weijiang Chu Gen Xiong Ruilong Shi Xiangming Ge Jingfang Zhang Qingxiang Meng

This study presents the design and performance assessment of suction anchor foundations for an integrated offshore wind–solar–aquaculture system located in Jiangsu Sheyang, China. The project represents one of the first practical demonstrations of coupling renewable energy production with large-scale marine aquaculture on a shared floating platform. Using three-dimensional numerical simulations in FLAC3D and ABAQUS, the study evaluates the anchors’ bearing capacity, structural safety, and fatigue performance under ultimate (ULS), accidental (ALS), and fatigue (FLS) limit states. The analysis incorporates site-specific geotechnical conditions, seabed scour, and installation deviations, providing a realistic framework for foundation design in layered coastal sediments. Results confirm that the suction anchor system meets international safety requirements (DNV, CCS) and maintains robust performance throughout its service life. The findings demonstrate that scour depth and installation accuracy are critical factors governing anchor reliability and offer practical insights for updating offshore foundation design standards in future multifunctional renewable–aquaculture developments.

CivilEng doi: 10.3390/civileng6040053

Authors: Lu Liu Zhouhong Zong Yulin Shan Yao Yao Chenglin Li Yihao Cheng

Explosions, including those from war weapons, terrorist attacks, etc., can lead to damage and overall collapse of bridges. However, there are no clear guidelines for anti-blast design and protective measures for bridges under blast loading in current bridge design specifications. With advancements in intelligent construction, precast segmental bridge piers have become a major trend in social development. There is a lack of full understanding of the anti-blast performance of precast segmental bridge piers. To study the engineering calculation method for blast load acting on a typical precast segmental reinforced concrete (RC) pier in near-field explosions, an air explosion test of the precast segmental RC pier is firstly carried out, then a fluid–structure coupling numerical model of the precast segmental RC pier is established and the interaction between the explosion shock wave and the precast segmental RC pier is discussed. A numerical simulation of the precast segmental RC pier in a near-field explosion is conducted based on a reliable numerical model, and the distribution of the blast load acting on the precast segmental RC pier in the near-field explosion is analyzed. The results show that the reflected overpressure on the pier and the incident overpressure in the free field are reliable. The simulation results are basically consistent with the experimental results (with a relative error of less than 8%), and the fluid–structure coupling model is reasonable and reliable. The explosion shock wave has effects of reflection and circulation on the precast segmental RC pier. In the near-field explosion, the back and side blast loads acting on the precast segmental RC bridge pier can be ignored in the blast-resistant design. The front blast loads can be simplified and equalized, and a blast-resistant design load coefficient (1, 0.2, 0.03, 0.02, and 0.01) and a calculation formula of maximum equivalent overpressure peak value (applicable scaled distance [0.175 m/kg1/3, 0.378 m/kg1/3]) are proposed, which can be used as a reference for the blast-resistant design of precast segmental RC piers.

CivilEng doi: 10.3390/civileng6030052

Authors: Shuhan Wang Long Li Xianfei Yin Ziwei Yi Shu Shi Meiqi Wan

The complexities of megaprojects, particularly major transportation infrastructure projects (MTIs), require technological innovation that advances economic, social, and ecological objectives. Traditional engineering innovation emphasizes economic gains while neglecting sustainability. Therefore, implementing green innovation (GI) in MTIs is essential. This research examines key factors and correlations influencing MTI-GI to strengthen theoretical understanding and guide effective implementation. First, literature and interviews are used to identify MTI-GI influencing factors through the technology–organization–environment (TOE) framework. Second, an intuitive fuzzy number approach reduces subjectivity in expert scoring and, combined with the DEMATEL method, constructs a fuzzy DEMATEL model to quantify factor importance and identify critical drivers. Critical factors are then analyzed to formulate GI promotion strategies. Results reveal that MTI-GI influencing factors span technology, organization, and environment dimensions. Prioritizing green technological innovation and feedback mechanisms, optimizing organizational structures, and aligning with regional environmental characteristics are crucial for successful MTI-GI implementation. These findings support GI expansion in MTIs and offer targeted strategies for managing complex systems.

CivilEng doi: 10.3390/civileng6030051

Authors: Mortada Sabeh Whwah Mushtaq Sadiq Radhi Anmar Dulaimi Luís Filipe Almeida Bernardo Tiago Pinto Ribeiro

This research investigates the influence of incorporating perlite aggregate and silica fume on the properties of cement mortar, with a focus on compressive strength, flexural strength, density, water absorption, and thermal conductivity. The results show that increasing the percentage of perlite (Pe) in the mixes causes a marked reduction in the compressive strength, reflecting the lightweight nature and low density of perlite. For mixes with Pe-20% through Pe-100%, the compressive strength decreased by up to 78% compared to the reference mix. However, the addition of silica fume (SF) in mixes with SF-20% to SF-100% partially offset this effect, limiting the strength losses to 18–71%, which indicates that silica fume contributes to strength enhancement over time. The flexural strength followed a similar trend, decreasing with a higher perlite content: reductions of up to 40% were observed for Pe mixtures, while SF mixes showed slightly smaller decreases, reaching 36%. The density also declined consistently with increasing perlite replacement, with a maximum reduction of 57% in mix Pe-100% due to the inherent porosity of perlite. The water absorption increased substantially in the same mix (Pe-100%), by 327% compared to the reference one, whereas the addition of silica fume (SF-100%) limited the increase to 181%, confirming its role in refining the pore structure. The thermal conductivity decreased with a higher perlite content, attributed to the formation of voids in the matrix. The lowest value was observed for Pe-100%, with an 82% reduction, while silica fume mixes also showed reductions of 37–81% relative to the reference mix. Based on a comprehensive evaluation of strength, density, water absorption, and thermal performance, mix SF-60% was identified as the optimal mixture, offering a balanced profile with a compressive strength of 4.4 MPa, thermal conductivity of 0.28 W/(m·K), and density of 1089 kg/m3. These performance levels make the developed mortars particularly suitable for non-load-bearing masonry units, lightweight blocks, and insulation panels, where reduced weight and enhanced thermal efficiency are essential. The study therefore provides practical guidance for the design of sustainable, lightweight mortars for energy-efficient construction applications.

CivilEng doi: 10.3390/civileng6030050

Authors: Jhabindra Poudel Prashidha Khatiwada Subash Adhikari

Earthquakes remain among the most destructive natural hazards, causing severe loss of life and property in seismically active regions such as Nepal. Major events such as the 1934 Nepal–Bihar earthquake (Mw 8.2), the 2015 Gorkha earthquake (Mw 7.8), and the 2023 Jajarkot earthquake (ML 6.4) have repeatedly exposed the vulnerability of Nepal’s built environment. In response, the Ready-to-Use Detailing (RUD) guideline (NBC 205:2024) was introduced to provide standardized structural detailing for low-rise reinforced concrete buildings without masonry infill, particularly for use in areas where access to professional engineering services is limited. This study was motivated by the need to critically assess the structural performance of buildings designed according to such rule-of-thumb detailing, which is widely applied through owner–builder practices. Nonlinear pushover analyses were carried out using finite element modelling for typical configurations on soil types C and D, under peak ground accelerations of 0.25 g, 0.30 g, 0.35 g, and 0.40 g. The response spectrum from NBC 105:2020 was adopted to determine performance points. The analysis focused on global response, capacity curves, storey drift, and hinge formation to evaluate structural resilience. The maximum story drift for the linear static analysis is found to be 0.56% and 0.86% for peak ground acceleration of 0.40 g, for both three and four-storied buildings. Also, from non-linear static analysis, it is found that almost all hinges formed in the beams and columns are in the Immediate Occupancy (IO) level. The findings suggest that the RUD guidelines are capable of providing adequate seismic performance for low-rise reinforced concrete buildings, given that the recommended material quality and construction standards are satisfied.

CivilEng doi: 10.3390/civileng6030049

Authors: Yannik Schwarz David Sanio Peter Mark

Conventional strengthening measures for existing structures are usually not effective for the self-weight, which accounts for around 70% of the total load in reinforced concrete structures. Therefore, their effect on the overall load-bearing capacity is low. A self-weight-effective alternative for flexural strengthening is the thermal prestressing of additional reinforcement installed on the structure. In this method, reinforcing bars are slotted into the tensile zone, embedded in filler material, and tempered from the outside. They are thermally stretched, and once cooling starts, the bond with the hardened filler prevents re-deformation. The induced prestressing force counteracts dead loads and relieves the tensile zone, making the additional bars effective for the self-weight. In this paper, the effectiveness of the strengthening method is experimentally investigated in the serviceability and the ultimate limit states. Experiments involve strengthening a reinforced concrete beam under load by a thermally prestressed additional bar. Moreover, two reference tests are made to evaluate the method. An unstrengthened beam characterizes the lower capacity limit. Another beam with the same reinforcement amount as the strengthened one, but completely installed at casting, serves as the upper benchmark. All beams are loaded until bending failure. The strengthening method is assessed by means of the load-bearing behavior, deflection, crack development, and the strains in the initial as well as the added reinforcement. The results demonstrate the effectiveness of the strengthening method. The thermally prestressed bar achieves an effective pre-strain of approximately. 0.4‰ by heating at about 70 °C. The induced prestressing force and associated compression reduce tensile cracks by approx. 45% and increase stiffness. The strengthened beam reaches the maximum load of the upper benchmark, but with about 33% less deflection. The filler, which also expands thermally, generates an additional prestressing force that is effective up to about 20% of the load capacity. Beyond this, the filler begins to crack and its effect decreases, but the pre-strain in the reinforcing bar remains until maximum load.

CivilEng doi: 10.3390/civileng6030048

Authors: Gregor Trtnik Jakob Šušteršič Tomaž Hozjan

This study presents the outcomes of a comprehensive experimental investigation focused on the bond behavior between reinforcing steel bars and tremie concrete, assessed through standardized pull-out tests. The objective was to evaluate the influence of some key parameters: reinforcement bar diameter, concrete age (and associated compressive strength), steel fiber content, and a bentonite coating on rebar surfaces. Experiments were conducted under laboratory conditions according to relevant standards. Slip between the reinforcement and tremie concrete was measured using a sophisticated high-precision optical laser device, enabling accurate assessment of bond characteristics. A large, i.e., a statistically sufficient, number of specimens was tested, allowing the results to be analyzed using the ANOVA technique to determine the statistical significance of each parameter. The results show that, under most test conditions, the influence of the bentonite suspension coating on the bond strength was not statistically significant. Similarly, variations in the bar diameter and fiber content showed no statistically significant impact within the tested ranges. In contrast, concrete age (compressive strength) exhibited a statistically significant influence, confirming that concrete maturity is a dominant factor in bond development. The results contribute to a better understanding of the bond mechanisms in reinforced concrete and can assist in optimizing design strategies where bond performance is critical.

CivilEng doi: 10.3390/civileng6030047

Authors: Moein Mousavi Prasad Rangaraju

The growing application of 3D concrete printing (3DCP) in construction has raised important questions regarding its long-term durability under freeze–thaw (F–T) exposure, particularly in cold climates. This review paper presents a comprehensive examination of recent research focused on the F–T performance of 3D-printed concrete (3DPC). Key material and process parameters influencing durability, such as print orientation, admixtures, and layer bonding, are critically evaluated. Experimental findings from mechanical, microstructural, and imaging studies are discussed, highlighting anisotropic vulnerabilities and the potential of advanced additives like nanofillers and air-entraining agents. Notably, air-entraining agents (AEA) reduced the compressive strength loss by 1.4–5.3% after exposure to F–T cycles compared to control samples. Additionally, horizontally cored specimens with AEA incorporated into their mixture design showed a 15% higher dynamic modulus after up to 300 F–T cycles. Furthermore, optimized printing parameters, such as reduced nozzle standoff distance and minimized printing time gap, reduced surface scaling by over 50%. The addition of a nanofiller such as nano zinc oxide in 3DPC can result in compressive strength retention rates exceeding 95% even after aggressive F–T cycling. The lack of standard testing protocols and the geometry dependence of degradation are emphasized as key research gaps. This review provides insights into optimizing mix designs and printing strategies to improve the F–T resistance of 3DPC, aiming to support its reliable implementation in cold-region infrastructure.

CivilEng doi: 10.3390/civileng6030046

Authors: Anmar Dulaimi Yasir N. Kadhim Qassim Ali Al Quraishy Hayder Al Hawesah Tiago Pinto Ribeiro Luís Filipe Almeida Bernardo

The use of hot mix asphalt (HMA) has several drawbacks, such as the emission of harmful gases into the atmosphere, difficulties in maintaining temperature over long distances, and the requirement for high energy consumption during preparation and installation. In order to solve these issues, this research aimed to produce High-Performance Cold Mix Asphalt (HP-CMA), in which Ordinary Portland Cement (OPC) is used as a filler to replace limestone filler at 0%, 1.5%, 3%, 4.5%, and 6% of the aggregate weight. Indirect Tensile Stiffness Modulus (ITSM), moisture susceptibility, temperature susceptibility, and microstructural analysis tests were carried out. The results showed that the ITSM was considerably enhanced when OPC was utilized. When comparing HP-CMA with 3% OPC to the control HMA (100–150 pen), the ITSM increased by approximately 80% after three days. In contrast, HP-CMA with 4.5% OPC achieved the same ITSM as the control HMA (40–60 pen) after seven days. Moreover, the ITSM of the HMA 40–60 pen decreased by 91.93% when the temperature rose from 20 °C to 45 °C, whereas the ITSM of the HP-CMA with 6% OPC decreased by 42.47% over the same temperature range. This suggests that HP-CMA is more stable than the HMA 40–60 pen at elevated temperatures. The superior performance of the HP-CMA can be attributed to two essential factors: the improved binding effect due to the demulsification of the asphalt emulsion used as a binder, and the formation of hydration products from the added cement.

CivilEng doi: 10.3390/civileng6030045

Authors: Saman Hedjazi Macy Spears Ehsanul Kabir Hossein Taheri

Ground penetrating radar (GPR) is a non-destructive testing (NDT) method increasingly used for evaluating concrete structures by identifying internal flaws and embedded objects. This study presents a structured image-based methodology for interpreting GPR B-scan data using a practical flowchart designed to aid in distinguishing common subsurface anomalies. The methodology was validated through a laboratory experiment involving four concrete slabs embedded with simulated defects, including corroded rebar, hollow pipes, polystyrene sheets (to represent delamination), and hollow containers (to represent voids). Scans were performed using a commercially available device, and the resulting radargrams were analyzed based on signal reflection patterns. The proposed approach successfully identified rebar positions, spacing, and depths, as well as low-dielectric anomalies such as voids and polystyrene inclusions. Some limitations were noted in detecting non-metallic materials with weak dielectric contrast, such as hollow pipes. Overall, the findings demonstrate the reliability and adaptability of the proposed method in improving the interpretation of GPR data for structural diagnostics. The proposed methodology achieved a detection accuracy of approximately 90% across all embedded features, which demonstrates improved interpretability compared to traditional manual GPR assessments, typically ranging between 70 and 80% in similar laboratory conditions.

CivilEng doi: 10.3390/civileng6030044

Authors: Jaime R. Ramírez-Vargas Sergio A. Zamora-Castro Agustín L. Herrera-May Rafael Melo-Santiago Luis Carlos Sandoval Herazo Domingo Pérez-Madrigal

Recycled asphalt pavement (RAP) can support traffic loads comparable to those of roads constructed with conventional materials. The structural evaluation of RAP is performed through the deflection generated by vehicles via recoverable deflection in the pavement layers. The deflection record is translated into a curve that geometrically interprets the behavior of the layers that make up the pavement. In this study, a falling weight deflectometer (FWD) was used to emulate transit loads and measure deflection in two models. Both contained 30% RAP, and one of them had fiberglass geogrid in the center of the asphalt layer. Through normalized maximum deflection (limit value based on constant stress), the structural index (SI), and the dynamic stiffness modulus (DSM), the structural behavior of the models under different load levels was evaluated. The pavement structure exhibited similarities in strength for both models subjected to impact. The presence of the geogrid reinforcement (Z1) showed structural index values ranging between 0.17 and 0.54, while the layer without geogrid (Z2) presented structural index values in a range of 0.23 to 0.78. In addition, the dynamic stiffness modulus presented a difference of 10 kN/mm between the maximums of the models in favor of reinforcement with glass fiber geogrid. Therefore, low structural index values are associated with the interaction between RAP and geogrid, highlighting this combination as an innovative and functional system for road surfaces, while the dynamic stiffness modulus indicates the stability and structural integrity of sustainable pavement, which has the potential to extend its lifespan.

CivilEng doi: 10.3390/civileng6030043

Authors: Ghasan Fahim Huseien Mohammad Hajmohammadian Baghban Iman Faridmehr Kaijun Dong

In the construction sector, cement and concrete are among the most widely utilized manufactured materials, yet their environmental impact remains a significant concern. The concrete industry is a major contributor to carbon dioxide emissions, accounting for over 8% of global greenhouse gas emissions annually. Several reports have estimated that between 1930 and 2013, a total of 4.5 gigatons of carbon was sequestered through the carbonation of cement-based materials. This process offset approximately 43% of the carbon dioxide (CO2) emissions resulting from cement production during the same period, excluding emissions related to fossil fuel consumption in the manufacturing process. It is well established that producing one ton of cement results in approximately 0.60–0.98 tons of CO2 emissions, coupled with substantial energy consumption. To mitigate these environmental effects, developing low-carbon or cement-free binders has become crucial. Alkali-activated binders (AABs), derived from industrial by-products or agricultural waste materials and activated with a low-molarity or one-part activator, are increasingly recommended as sustainable alternatives to reduce greenhouse gas emissions in the cement industry and minimize the consumption of natural resources. The production of alkali-activated concrete (AAC) involves several critical factors that significantly influence its mix design, fresh properties, and compressive strength (CS) performance. This study aims to provide a comprehensive review of the key factors affecting AAC’s mix design, workability, and CS characteristics. Firstly, the study discusses various methods employed for AAC mix design and the factors influencing these designs. Secondly, it examines the impact of binder type, source, chemical, mineralogical, and physical properties, as well as alkaline activator solutions, water content, and fillers on AAC’s workability, setting times, and strength development. Additionally, the study explores the correlation matrix and predictive performance models for fresh and strength properties. Lastly, the relationship between workability and CS is extensively analyzed. The review concludes by highlighting the existing challenges and prospects of AACs as sustainable construction materials to replace traditional cement and reduce carbon emissions.

CivilEng doi: 10.3390/civileng6030042

Authors: Pingan Liu Yupeng Ou Tiehu Wang Fei Yue Yingming Zhen Xun Zhang

This study presents a comprehensive analysis of hydration heat-induced temperature and stress fields in a U-shaped aqueduct during the casting phase, integrating field measurements and numerical simulations. The key findings are as follows: (1) Thermal Evolution Characteristics: Both experimental and numerical results demonstrated consistent thermal behavior, characterized by a rapid temperature rise, subsequent rapid cooling, and eventual stabilization near ambient conditions. The peak temperature is observed at the centroid of the bearing section’s base slab, reaching 83.8 °C in field tests and 87.0 °C in simulations. (2) Stress Field Analysis: Numerical modeling reveals critical stress conditions in the outer concrete layers within high-temperature zones. The maximum tensile stress reaches 6.37 MPa, exceeding the allowable value of the tensile strength of the current concrete (1.85 MPa) by 244%, indicating a significant risk of thermal cracking. (3) Temperature Gradient and Cooling Rate Anomalies: Both methodologies identify non-compliance with critical control criteria. Internal-to-surface temperature differentials exceed the 25 °C threshold. Daily cooling rates at monitored locations surpass 2.0 °C/d during the initial 5–6 days of the cooling phase, elevating cracking risks associated with excessive thermal gradients. (4) Mitigation Strategy Proposal: Implementation of a hydration heat control system is recommended; compared to single-layer systems, the proposed mid-depth double-layer steel pipe cooling system (1.2 m/s flow) reduced peak temperature by 23.8 °C and improved cooling efficiency by 28.7%. The optimized water circulation maintained thermal balance between concrete and cooling water, achieving water savings and cost reduction while ensuring structural quality. (5) The cooling system proposed in this paper has certain limitations in terms of applicable environment and construction difficulty. Future research can combine with a BIM system to dynamically control the tube cooling system in real time.

CivilEng doi: 10.3390/civileng6030041

Authors: Zahraa Ahmed al-Mammori Israa Mohsin Kadhim Al-Janabi Ghadeer H. Abbas Doaa Hazim Aziz Fatin H. Alaaraji Elaf Salam Abbas Beshaer M. AL-shimmery Tameem Mohammed Hashim Ghanim Q. Al-Jameel Ali Shubbar Mohammed Salah Nasr

With rising global temperatures and increasing sustainability demands, the need for advanced pavement solutions has never been greater. This study breaks new ground by integrating phase change materials (PCMs), including paraffin-based wax (Rubitherm RT55), hydrated salt (Climator Salt S10), and fatty acid (lauric acid), as binder modifiers within warm mix asphalt (WMA) mixtures. Moving beyond the traditional focus on binder-only modifications, this research utilizes recycled cigarette filters (CFs) as a dual-purpose fiber additive, directly reinforcing the asphalt mixture while simultaneously transforming a major urban waste stream into valuable infrastructure. The performance of the developed WMA mixture has been evaluated in terms of stiffness behavior using an Indirect Tensile Strength Modulus (ITSM) test, permanent deformation using a static creep strain test, and rutting resistance using the Hamburg wheel-track test. Laboratory tests demonstrated that the incorporation of PCMs and recycled CFs into WMA mixtures led to remarkable improvements in stiffness, deformation resistance, and rutting performance. Modified mixes consistently outperformed the control, achieving up to 15% higher stiffness after 7 days of curing, 36% lower creep strain after 4000 s, and 64% reduction in rut depth at 20,000 passes. Cost–benefit analysis and service life prediction show that, despite costing USD 0.71 more per square meter with 5 cm thickness, the modified WMA mixture delivers much greater durability and rutting resistance, extending service life to 19–29 years compared to 10–15 years for the control. This highlights the value of these modifications for durable, sustainable pavements.

CivilEng doi: 10.3390/civileng6030040

Authors: Xiaohua Wang Chonghao Sun Junjie Dong Xiangbo Du Yuan Lu Qianqing Zhang Kang Sun

In this study, to solidify the silt in an expressway, a stabilizing agent composed of industrial wastes, such as ordinary Portland cement (OPC), calcium based alkaline activator (CAA), silicate solid waste material (SISWM) and sulfate solid waste material (SUSWM) was developed. Orthogonal experiments and comparative experiments were carried out to analyze the strength and water stability of the stabilized silt, and get the optimal proportion of each component in the stabilizing agent. A series of laboratory tests, including unconfined compressive strength (UCS), water stability (WS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses, were conducted on solidified silt samples treated with the stabilizing agent at optimal mixing ratios of OPC, CAA, SISWM, and SUSWM to elucidate the evolution of mineral composition and microstructure.

CivilEng doi: 10.3390/civileng6030039

Authors: Marike Bornholdt Martin Herbrand Kay Smarsly Gerhard Zehetmaier

Earthen flood protection structures are planned and constructed with an expected service life of several decades while being exposed to environmental impacts that may lead to structural or hydraulic failure. Current maintenance procedures involve only repairing external damage, leaving internal processes contributing to structural damage often undetected. Through structural health monitoring (SHM), structural deficits can be detected before visible damage occurs. To improve maintenance workflows and support predictive maintenance of dikes, this paper reports on the integration of digital twin concepts with SHM strategies, referred to as “digital-twin-based SHM”. A digital twin concept, including a standard-compliant building information model, is proposed and implemented in terms of a digital twin environment. For integrating monitoring and sensor data into the digital twin environment, a customized webform is designed. A communication protocol links preprocessed sensor data stored on a server with the digital twin environment, enabling model-based visualization and contextualization of the sensor data. As will be shown in this paper, a digital twin environment is set up and managed in the context of SHM in compliance with technical standards and using well-established software tools. In conclusion, digital-twin-based SHM, as proposed in this paper, has proven to advance predictive maintenance of dikes, contributing to the resilience of critical infrastructure against environmental impacts.

CivilEng doi: 10.3390/civileng6030038

Authors: Teuku Ferdiansyah Romaynoor Ismy Shaban Shahzad Waqas Rafiq Kashif Nadeem

Concrete resistivity is a critical parameter for assessing durability and monitoring the structural health of reinforced concrete. This study systematically evaluates the effects of the water-to-cement (w/c) ratio, saturation ratio (SR), and temperature on concrete resistivity using three different predictive models: linear regression, cubic Support Vector Machine (SVM), and Gaussian Process Regression (GPR). Each model was independently trained and tested to assess its ability to capture the nonlinear relationships between these key parameters. Experimental results show that resistivity decreases significantly under increasing load due to geometrical effects. For a w/c ratio of 0.4, resistivity decreases by −12.48% at 100% SR and by −6.68% at 60% SR under 20% loading. Higher w/c ratios (0.5 and 0.6) exhibit more pronounced resistivity reductions due to increased porosity and ion mobility, with a maximum decrease of −13.68% for w/c = 0.6. Among the developed predictive models, the Matern 5/2 Gaussian process regression (GPR) model demonstrated the highest accuracy, achieving an RMSE of 5.21, R2 of 0.99, MSE of 27.19, and MAE of 3.40, significantly outperforming the other approaches. Additionally, a permutation importance analysis revealed that the saturation ratio (SR) is the most critical variable influencing resistivity, followed by the water–cement ratio, while temperature has the least impact. These findings provide valuable insights into the durability assessment and corrosion prevention of reinforced concrete, offering practical implications for the optimization of material design and structural health monitoring in civil engineering.

CivilEng doi: 10.3390/civileng6030037

Authors: Nicola De Fazio Luca Placidi Francesco Fabbrocino Raimondo Luciano

In this study, we aim to analyze the dispersion of ultrasonic waves due to second-gradient contributions and attenuation within the framework of continuum mechanics. To investigate dispersive behavior and attenuation effects, we consider the influence of both higher-order gradient terms (second gradients) and Rayleigh-type viscoelastic contributions. To this end, we employ the extended Rayleigh–Hamilton principle to derive the governing equations of the problem. Using a wave-form solution, we establish the relationship between the phase velocity and the material’s constitutive parameters, including those related to the stiffness of both standard (first-gradient) and second-gradient types, as well as viscosity. To validate the model, we use data available in the literature to identify all the material parameters. Based on this identification, we observe that our model provides a good approximation of the experimentally measured trends of both phase velocity and attenuation versus frequency. In conclusion, this result not only confirms that our model can accurately describe both wave dispersion and attenuation in a material, as observed experimentally, but also highlights the necessity of simultaneously considering both second-gradient and viscosity parameters for a proper mechanical characterization of materials.

CivilEng doi: 10.3390/civileng6030036

Authors: Xian Gao Xilong Chen Kun Lu Xueyuan Deng

Although prefabricated buildings offer environmental advantages, their construction process inevitably generates environmental impacts. However, current research on prefabricated buildings focuses on the environmental impact level, and there is a lack of intelligent tools for analyzing their spatial and temporal dimensions. Therefore, this study develops a framework using 5D building information modeling (BIM) to monetize environmental impacts into environmental costs for prefabricated building construction. This framework includes defining boundaries and indicators, obtaining a resource inventory using the 5D BIM coding system, calculating environmental impact results, and converting environmental impacts into environmental costs. Taking a prefabricated substation as a case study, its environmental costs are 172.81 CNY/m2, with these costs caused by climate change accounting for the largest proportion (91.2%). This study unifies different environmental impacts into a single monetary form, providing stakeholders with intuitive indicators. It also expands 5D BIM applications from conventional costs to environmental costs, which can display their spatiotemporal changes.

CivilEng doi: 10.3390/civileng6030035

Authors: Haining Wang Yuhe Zhang Yang Wang Weizhe Feng Jie Li Kaixing Zhang Yu Rong Zhanyong Yao Kai Yao

The Deep Cement Mixing Integrated Drilling, Mixing, and Jetting (DMJ) technique was innovatively developed by incorporating high-pressure jetting apertures into the mixing blades to enhance the bearing capacity of deep cement-mixed piles. In this study, the bearing characteristics of DMJ pile composite foundations under embankment loading are investigated using numerical simulation. Through comparative simulations involving various pile configurations, the results demonstrate that DMJ pile composite foundations exhibit significantly enhanced settlement control compared to conventional deep mixing piles. Notably, under identical area replacement ratios, the use of DMJ piles reduces total foundation settlement by approximately 30%. Furthermore, the findings indicate that larger pile diameters and smaller spacing are particularly effective in minimizing settlement. In terms of load transfer efficiency, DMJ piles are capable of transmitting embankment loads to depths of up to 15 m, surpassing the 10 m transfer depth observed in conventional pile systems. An analysis of excess pore water pressure further reveals that DMJ piles promote more effective dissipation, highlighting their superior performance in maintaining foundation stability under embankment loading.

CivilEng doi: 10.3390/civileng6030034

Authors: Konstantinos I. Christidis

The present research aims to the evaluation of the deformation capacity of existing reinforced concrete shear walls designed with past non-conforming seismic regulations. A refined analytical model (referred to as the Proposed Model) is presented for generating Load–displacement (P-d) curves for RC shear walls. The model is applicable to medium-rise walls designed with or without modern seismic provisions and incorporates shear effects in both deformation and strength capacity. The application of the Proposed Model is assessed through comparison with numerical models implemented in the widely accepted OpenSees platform. Specifically, two types of elements are examined: the widely used flexural element Force-Based Beam-Column Element (FBE) and the Flexure-Shear Interaction Displacement-Based Beam-Column Element (FSI), which accounts for the interaction between flexure and shear. The results of both analytical and numerical approaches are compared with experimental data from four RC shear wall specimens reported in previous studies.

CivilEng doi: 10.3390/civileng6030033

Authors: M. A. Karim Youngguk Seo Ibrahim Alamayreh Stuart Suttle

This study is a preliminary investigation of the independent utilization of two types of fly ash (FA)–FA Type C and FA Type F-as partial replacement of fine aggregate (sand) and cement in Portland cement concrete (PCC) mixes. The main objective was to determine an optimum substitution range for each type of FA that would offer well-performing concrete in terms of workability, compressive strength, and durability. To this end, multiple concrete batches were prepared, incorporating each type of FA at four different levels: 5%, 10%, 15%, and 20% by weight of fine aggregate replacement and 10%, 20%, 30%, and 40% by weight for cement replacement. Then, concrete samples (100 mm diameter × 200 mm tall cylinders) were cast from each batch and were moisture-cured for 7, 14, and 28 days prior to testing. The addition of FA contributed positively to the strength development at specific replacement levels: all percentages for both FA Type C and Type F for fine aggregate replacement and up to 30% FA content for both Type C and F for cement replacement, 10% for both FA Type C and Type F provided the higher strength for aggregate replacement, and 10–20% for both types of FA provided the higher strength for cement replacement. Furthermore, these additions of FA exhibited comparable workability and durability except for FA Type F, which did not exhibit comparable workability for aggregate replacement. FA Type C can be recommended for both early and long-term strength for fine aggregate replacement, whereas FA Type C is suggested to be used for early strength and Type F provides for long-term strength for cement replacement. Type C provides better durability and Type F provides better workability for cement replacement.

CivilEng doi: 10.3390/civileng6020032

Authors: Ahmad Akib Uz Zaman Ahmed Abdelaty Mohamed S. Yamany

As transportation infrastructure systems continue to expand, the demand for unmanned aerial vehicle (UAV) technologies in the assessment of urban infrastructure is expected to grow substantially, due to their strong potential for efficient data collection and post-processing. UAVs offer numerous advantages in infrastructure assessment, including enhanced time and cost efficiency, improved safety, and the ability to capture high-quality data. Furthermore, integrating various data-collecting sensors enhances the versatility of UAVs, enabling the acquisition of diverse data types to support comprehensive infrastructure evaluations. Numerous post-processing software applications utilizing various structure-from-motion (SfM) techniques have been developed, significantly facilitating the assessment process. However, researchers’ efforts to find the potentialities of this technology will be in vain if its applications are not utilized effectively in the practical field. Therefore, this study aims to determine the adaptation condition of UAV technologies in different Department of Transportation (DOT) and Federal Highway Administration (FHWA) agencies to assess transportation infrastructure systems. This study also explores the quantitative analysis of benefits and challenges/barriers, expectations for every UAV and post-processing software, and the cutting-edge features that should be integrated with UAVs to effectively evaluate transportation infrastructure systems. A comprehensive survey form was distributed to all 50 DOTs and the FHWA, and 35 complete responses were recorded from 27 DOTs and the FHWA. The survey results show that 25 agencies currently use UAVs for roads or highways, and 23 DOTs for bridges, confirming these as the most commonly assessed infrastructure systems. The top benefits found in this study include safety, cost effectiveness, and time efficiency (mean ratings: 3.95–4.28), while weather, FAA regulations, and airspace restrictions are the main challenges. Respondents emphasize the need for longer flight times, better automation, and advanced data tools, underscoring growing adoption and highlighting the need to overcome technical, regulatory, and data privacy challenges for optimal UAV integration within transportation infrastructure systems management.

CivilEng doi: 10.3390/civileng6020031

Authors: Carmine P. Polito James R. Martin

Over the past several decades, extensive research has advanced the understanding of liquefaction in clean sands and sand–silt mixtures under seismic loading. However, the influence of plastic (i.e., clayey) fines on the liquefaction behavior of sandy soils remains less well understood. This study investigates how the quantity and plasticity of fines affect both the susceptibility to liquefaction and the resulting failure mode. A series of stress-controlled cyclic triaxial tests were conducted on sand specimens containing varying proportions of non-plastic silt, kaolinite, and bentonite. Specimens were prepared at a constant relative density with fines content ranging from 0% to 37%. Two liquefaction modes were examined: flow liquefaction, characterized by sudden and large strains under undrained conditions, and cyclic mobility, which involves gradual strain accumulation without complete strength loss. The results revealed a clear relationship between soil plasticity and liquefaction mode. Specimens containing non-plastic fines or fines with a liquid limit (LL) below 20% and a plasticity index (PI) of 0 exhibited flow liquefaction. In contrast, specimens with LL > 20% and PI ≥ 7% consistently displayed cyclic mobility behavior. These findings help reconcile the apparent contradiction between laboratory studies, which often show increased liquefaction susceptibility with plastic fines, and field observations, where clayey soils frequently appear non-liquefiable. The study emphasizes the critical role of plasticity in determining liquefaction type, providing essential insight for seismic risk assessments and design practices involving fine-containing sandy soils.

CivilEng doi: 10.3390/civileng6020030

Authors: Pushparaj A. Naik Shriram Marathe

This study investigates the mechanical properties of pervious concrete incorporating river lateritic and quarry lateritic aggregates as sustainable alternatives to conventional aggregates. The research aims to evaluate the compressive strength, split tensile strength, and permeability of pervious concrete mixes with varying void ratios (20% and 24%) and aggregate sizes. The results indicate that pervious concrete containing quarry lateritic aggregates exhibits superior permeability due to its inherent porosity, while river lateritic aggregates provide relatively better compressive strength than quarry aggregates. However, both lateritic aggregates show lower mechanical strength than conventional pervious concrete. Additionally, Python-based predictive models employing multi-linear regression were developed to estimate compressive strength based on independent variables such as binder quantity, coarse aggregate content, water-to-cement ratio, and curing duration. The predictive models achieved R2 values of 0.69 for 7-day compressive strength and 0.82 for 28-day compressive strength, indicating strong predictive capabilities. This research highlights the potential of locally sourced materials in enhancing the sustainability of construction practices while offering valuable insights into the mechanical performance of pervious concrete and the utility of computational modeling for predicting concrete properties.

CivilEng doi: 10.3390/civileng6020029

Authors: Ali Alhakim Shen-En Chen Nicole L. Braxtan Brett Tempest Qiang Sun Wala’a Almakhadmeh Yuchun Zhang

When exposed to events such as fires or elevated temperatures, carbonation is an eventual outcome in cementitious building materials and can compromise the structural integrity of the material. Monitoring the pH levels in cement-based materials using color dyes, such as phenolphthalein, can offer insights into their chemical stability and the potential for early aging. These chemicals are traditionally used to detect carbonation depth in concrete, and recently, it has been suggested that they be applied to the concrete surface to determine the pH levels and the associated changes within these materials after heat treatment. This study utilizes image processing techniques to analyze the extent of fire damage by evaluating the primary color changes induced by phenolphthalein in cemented clay-based building materials. The primary color analysis can reduce the complexity in image processing, and while analyzing the color changes, it is found that the CMYK color model is superior to the RGB model for the cemented clay brick samples analyzed. The objective of this study is to develop rapid image processing techniques to automate the detection of carbonation in heat-treated cementitious materials. This study highlighted significant color transformations across different temperature exposures, providing valuable insights into the carbonation processes in burnt building materials. This study also identified the temperature range limitation (100 °C to 400 °C) of phenolphthalein indicators, which was not previously identified, and suggested the need for more robust carbonation indicators.

CivilEng doi: 10.3390/civileng6020028

Authors: Zhi-Qun Gong Yong-Zhi Wang Wei-Ke Zhou Shao-Ming Liao Yan-Qing Men Song-Chao Lin

The analysis of the impact of the construction of the subway protection zone on the adjacent subway tunnel has become the premise on which to ensure the safe operation of the tunnel. The need for expert members to carry out safety assessments based on specific calculations to determine the impact of construction on the safety of protected tunnels is extremely inconvenient for safety management and significantly reduces management efficiency. This paper analyzes and qualitatively judges the influence range and disturbance size of pile foundation construction, shallow foundation engineering, and foundation pit excavation. Based on relevant research results from scholars and numerical simulation methods, quantitative analysis and comparison are performed on the parameter sensitivity of pile foundation engineering, shallow foundation engineering, and foundation pit engineering along the subway line, and the influence of multi-factor combination is studied and discussed to obtain the influence sensitivity of each factor. The results show that the increase in pile spacing can effectively reduce the pile group effect. The sensitivity of subway tunnel settlement displacement is mainly controlled by the settlement displacement value. The larger the settlement displacement is, the stronger the sensitivity is. The loaded pile foundation arranged along the direction of the subway tunnel has more obvious disturbance to the subway tunnel than that arranged perpendicular to the direction of the subway tunnel.

CivilEng doi: 10.3390/civileng6020027

Authors: Shalaka Hire Sayali Sandbhor Kirti Ruikar

Automation is revolutionizing a number of sectors, including construction, by bringing about important technological breakthroughs that increase productivity and efficiency. Automation in safety procedures is still scarce though. In India, the majority of safety procedures are still reactive, manual, and paper-based. This study is a component of a broader research project on automated safety screening for fall risks enabled by BIM. It entails codification of OSHA rules to perform safety checks, placing corrective actions into location, and generating reports in a virtual environment. As part of the broader risk lifecycle, these tasks are typically completed on-site during the various stages of construction. This study, on the other hand, executes these steps in a virtual environment in the preconstruction phase. The model has been assessed in a pilot study in India and was developed especially to address fall hazards from staircases. Through early hazard identification and mitigation, the system assists professionals in enhancing overall safety performance.

CivilEng doi: 10.3390/civileng6020026

Authors: Qais Sahib Banyhussan Jaafar Abdulrazzaq Ahmed A. Hussein Anmar Dulaimi Jorge Miguel de Almeida Andrade Luís Filipe Almeida Bernardo

Various stabilizers, such as jute, gypsum, rice-husk ash, fly ash, cement, lime, and discarded rubber tires, are commonly used to improve the shear strength and overall characteristics of clay subgrade soil. In this study, waste foundry sand (WFS) is utilized as a stabilizing material to enhance the properties of clay subgrade soil and strengthen the bond between clay subgrade soil and subbase material. The materials employed in this study include Type B subbase granular materials, clay subgrade soil, and 1100 Biaxial Geogrid for reinforcement. The clay subgrade soil was collected from the airport area in the Al-Muthanna region of Baghdad. To evaluate the effectiveness of WFS as a stabilizer, soil specimens were prepared with varying replacement levels of 0%, 5%, 10%, and 15%. This study conducted a Modified Proctor Test, a California Bearing Ratio test, and a large-scale direct shear test to determine key parameters, including the CBR value, maximum dry density, optimum moisture content, and the compressive strength of the soil mixture. A specially designed large-scale direct shear apparatus was manufactured and utilized for testing, which comprised an upper square box measuring 20 cm × 20 cm × 10 cm and a lower rectangular box with dimensions of 200 mm × 250 mm × 100 mm. The findings indicate that the interface shear strength and overall properties of the clay subgrade soil improve as the proportion of WFS increases.

CivilEng doi: 10.3390/civileng6020025

Authors: Baraa A. Alfasi Ata M. Khan

Assessing risk in life-cycle cost and benefit estimates of highway investments is recommended by major organizations such as the World Bank and the U.S. Federal Highway Administration. This challenging task needs methodological support. Mutually exclusive investment alternatives can differ in terms of the costs of construction, maintenance, rehabilitation, and end-of-life value. Due to many causal factors and the long life of highway infrastructure, these items cannot be estimated with certainty. To go beyond the study of the sources of uncertainty, a method is needed to check the economic feasibility of acquiring additional information for deeper insight. This paper reports on research on the value of Bayesian pre-posterior information for refining the life-cycle cost analysis of uncertain costs and benefits for evaluating highway investment alternatives. Example applications demonstrate how the Bayesian pre-posterior analysis can be applied to check the feasibility of obtaining new information for enhancing the life-cycle cost analysis of highway investments. The value of Bayesian pre-posterior information is illustrated for reducing risk. Also, depending upon the specifics of uncertain states, a change in the choice of the investment alternative for implementation can be investigated. The product of this research can potentially upgrade highway infrastructure planning and management practices.

CivilEng doi: 10.3390/civileng6020024

Authors: Mohammed Al-Fatlawi Fatima Muslim Hadi Baneen M. H. Al-khafaji Sally Selan Hussein Tamar Maitham Al-Asedi Maryam M. Al-Aarajy Ashraf Anwar Al-Khazraji Tameem Mohammed Hashim Ali Shubbar Mohammed Salah Nasr Thair J. Alfatlawi

Pavement deterioration is often the result of intense traffic and increased runoff from storms, floods, or other environmental factors. A practical solution to this challenge involves the use of permeable pavements, such as permeable interlocking concrete pavement (PICP), which are designed to effectively manage water runoff while supporting heavy traffic. This research investigates the effectiveness of PICP in two distinct surface patterns: stretcher bond and 45° herringbone, by assessing their performance in terms of water infiltration and runoff using two different methods. The first approach has been conducted experimentally using a laboratory apparatus designed to simulate rainfall. Various conditions were applied during the performance tests, including longitudinal (L-Slope) and transverse (T-Slope) slopes of (0, 2, and 4%) and rainfall intensities of (40 and 80 L/min). The second approach has been implemented theoretically using Surfer 2.0 software to simulate the distribution of infiltrated water underneath the layers of PICP. Moreover, the behavior of PICP has been analyzed statistically using artificial neural networks (ANNs). The results indicated that at a rainfall intensity of 40 L/min, equal infiltration was observed in both patterns on 0% and 4% T-Slope. However, the 45° herringbone PICP showed better infiltration on the 8% T-Slope. Additionally, at 80 L/min rainfall, equal infiltration was observed in both patterns on 0% L-Slope for 0% and 4% T-Slope. The 45° herringbone PICP also demonstrated higher water infiltration on the 8% T-Slope, and this trend continued as the L-Slope increased. PICP with a 45° herringbone surface pattern exhibited superiority in reducing runoff compared to the stretcher bond pattern. The statistical models for the stretcher bond and 45° herringbone patterns demonstrate high accuracy, as evidenced by their correlation coefficient (R2) values of 99.97% and 97.32%, respectively, which confirms their validity. Despite the variations between the two forms of PICP, both are strongly endorsed as excellent alternatives to conventional pavement.

CivilEng doi: 10.3390/civileng6020023

Authors: Mohamed Algamati Abobakr Al-Sakkaf Ashutosh Bagchi

In order to ensure the safety of existing buildings constructed many years ago in zones with high seismicity, it is very important to consider and apply retrofitting measures. The seismic retrofitting of buildings can be achieved by techniques such as increasing the stiffness and ductility of the building and reducing the seismic demand. Energy dissipative devices such as various types of dampers are among the most popular and widely studied devices for improving the performance of buildings exposed to earthquakes. This paper presents a systematic literature review of the seismic retrofitting of existing buildings using energy dissipating devices. More than 230 journal and conference articles were collected from three well-known scientific resources published from 2010 to 2024. The main classification of papers considered was based on energy-dissipating devices employed for retrofitting goals. According to this analysis, there is a vast number of energy dissipative devices and design methods studied by scholars, and energy dissipation based on friction, viscous, and hysteretic mechanisms are the most useful for dampers. On the other hand, only relatively few articles were found about seismic loss assessment and the economic aspects of buildings retrofitted with the proposed damping tools.

CivilEng doi: 10.3390/civileng6020022

Authors: Emad Alshammari Mang Tia Othman Alanquri Abdullah Albogami Ahmed Alsabbagh Raid S. Alrashidi

Temperature variations have a significant impact on the performance and durability of rigid (concrete) pavement. As concrete is subjected to daily and seasonal temperature changes, it experiences thermal expansion and contraction. These movements, if not properly managed, can lead to cracking, joint deterioration, and loss of structural integrity. The pavement system is adversely affected by intense heat and significant flooding. This study aims to analyze the impact of several parameters on the performance of rigid pavement under typical, thermal, and flooding situations. This study investigates the properties of concrete and the dimensional design of rigid pavement with FEACONS IV software to assess their impact on the performance of concrete pavement during thermal and flooding conditions. The main conclusions of this study derived from the FEACONS IV analysis are as follows. Rigid pavement can enhance load-carrying capacity due to a lower elastic modulus, adequate flexural strength, and aggregates with a lower coefficient of thermal expansion. Increased thickness of concrete slabs and shorter slab lengths assist in minimizing load- and temperature-induced stresses. The increase in the subgrade modulus reaction value during flooding conditions improves pavement strength. However, in higher thermal conditions, a higher subgrade reaction modulus can increase the stress induced by temperature and load. Rigid pavement using porous limestone aggregate exhibits a reduced elastic modulus and coefficient of thermal expansion, suggesting higher resilience compared to rigid pavement composed of river gravel or granite. The findings suggest that higher thermal conditions will cause pavement damage. Agencies need to account for higher temperatures while designing and maintaining pavement. Flooding saturates the concrete pavement and subgrade layer, adversely affecting its performance over time.

CivilEng doi: 10.3390/civileng6020021

Authors: Suha Falih Mahdi Alazawy Mohammed Ali Ahmed Saja Hadi Raheem Hamza Imran Luís Filipe Almeida Bernardo Hugo Alexandre Silva Pinto

This study aims to develop a reliable method for predicting power plant construction costs during the early planning stages using ensemble machine learning techniques. Accurate cost predictions are essential for project feasibility, and this research highlights the strength of ensemble methods in improving prediction accuracy by combining the advantages of multiple models, offering a significant improvement over traditional approaches. This investigation employed the Random Forest (RF) algorithm to estimate the overall construction cost of a power plant. The RF algorithm was contrasted with single-learner machine learning models: Support Vector Regression (SVR) and k-Nearest Neighbors (KNN). Performance measures, comprising the coefficient of determination (R2), Mean Absolute Error (MAE), and Root Mean Squared Error (RMSE), were used to evaluate and contrast the performance of the implemented models. Statistical measures demonstrated that the RF approach surpassed alternative models, demonstrating the highest coefficient of determination for testing (R2=0.956) and the lowest Root Mean Square Error (RMSE = 29.27) for the testing dataset. The Shapley Additive Explanation (SHAP) technique was implemented to explain the significance and impact of predictor factors affecting power plant construction costs. The outcomes of this investigation provide crucial information for project decision-makers, allowing them to reduce discrepancies in projected costs and make informed decisions at the beginning of the construction phase.

CivilEng doi: 10.3390/civileng6020020

Authors: Anselmo S. Augusto Girum Urgessa Caio B. Amorim Robison E. Lopes Júnior Fausto B. Mendonça José A. F. F. Rocco Koshun Iha

Structural research teams face significant challenges when conducting studies with explosives, including the costs and inherent risks associated with field detonation tests. This study presents a replicable method for loading spherical and bare TNT-based cast explosive charges, offering reduced costs and minimal risks. Over eighty TNT and Composition B charges (comprising 60% RDX, 39% TNT, and 1% wax) were prepared using spherical molds made of thin aluminum, which are low-cost, off-the-shelf solutions. The charges were bare, meaning they lacked any casing, as the molds were designed to be easily removed after casting. The resulting charges were safer due to their smaller dimensions and the absence of hazardous metallic debris. Composition B charges demonstrated promising results, with their performance characterized through blast and thermochemical experiments. Comprehensive data are provided for Composition B charges, including TNT equivalence, pressures, velocity of detonation, DSC/TGA curves at four different heating rates, activation energy, peak decomposition temperatures, X-ray analysis, and statistics on masses and densities. A comparison between detonation and deflagration processes, captured in high-speed footage, is also presented. This explosive characterization is crucial for structural teams to precisely understand the blast loads produced, ensuring a clear and accurate knowledge of the forces acting on structures.

CivilEng doi: 10.3390/civileng6020019

Authors: Feilian Zhang Qicheng Wei Zhe Wu Jiawei Cao Danlin Jian Lantian Xiang

The surface settlement of railroad tunnels is dynamically updated as the construction progresses, exhibiting complex nonlinear characteristics. The accuracy of the on-site nonlinear regression fitting prediction method needs to be improved. To prevent surface settlement and surrounding rock collapse during railroad tunnel construction, while also ensuring the safety of the tunnel and existing structures, we propose a recursive prediction model for the long-term trend of surface settlement utilizing a singular spectrum analysis (SSA), improved sand cat swarm optimization (ISCSO), and a kernel extreme learning machine (KELM). First, SSA decomposition, known for its adaptive decomposition of one-dimensional nonlinear time series, reorganizes the early surface settlement data. The dynamic sliding window method is introduced to construct the prediction dataset, which is then trained using the KELM. ISCSO is used to optimize the key parameters of the KELM to obtain the long-term trend curves of surface settlement through recursive time series prediction. The superiority and effectiveness of ISCSO and the model are verified through numerical experiments and simulation experiments based on engineering cases, providing a reference for the early warning and control of surface settlement during the construction of similar tunnels.

CivilEng doi: 10.3390/civileng6020018

Authors: Hisashi Kakinohana Yuko Tanabe Yoshiaki Tamaki Tetsuhiro Shimozato

PC steel material inside pre-stressed concrete bridges is prone to corrosion due to the effect of salt, which leads to cross-sectional losses and fractures if proper maintenance is not carried out, affecting the girders’ structural performance. In Japan, pre-tensioned girders incorporating small-diameter PC steel material with a span length of 13 m or less were used until the early 1980s. Thus, it is essential to understand the fracture conditions of PC steel material and the factors affecting section loss due to corrosion, in order to properly assess the residual strength of salt-affected pre-tensioned girders. Hence, the current research clarifies the accuracy of techniques used for detecting deterioration in a pre-tensioned PC girder that had been out of service for about 40 years, caused by exposure to the severely saline environment of the Okinawa coast. Visual and hammer-tapping investigation of the actual bridge in addition to fracture investigation of the PC steel material using the triaxial magnetic method and destructive investigation of the concrete cover on the bottom of the girder were carried out and correlated. The final results confirmed that the triaxial magnetic method could detect PC steel material fractures accurately, and valuable information was obtained regarding fracture-detection technology for application in PC girders via non-destructive testing.

CivilEng doi: 10.3390/civileng6020017

Authors: Amira Ben Ameur Jan Valentin Nicola Baldo

Rising industrialization and population growth contribute to the increasing generation of plastic waste, which poses significant environmental and health challenges. Despite its potential as a resource, plastic waste is often discarded without proper treatment. Repurposing it in road construction offers both economic and environmental benefits, providing a sustainable waste management solution. This paper thoroughly examines various types of plastic waste used in asphalt mixtures, considering both wet and dry processing methods and their impact on bituminous binders and asphalt performance. Overall, incorporating waste plastics into asphalt mixtures has been shown to improve fatigue resistance, rutting resistance, moisture resistance, and high-temperature performance. However, challenges related to compatibility and low-temperature performance persist in plastic-modified asphalt applications. To address these issues, modified approaches, such as the use of chemical additives, have been identified as effective in enhancing the bonding between waste plastics and bituminous binders while also increasing the amount of plastic that can be incorporated. While plastic-modified asphalt shows significant promise, overcoming these challenges through targeted research and careful implementation is essential for its sustainable and effective use in asphalt mixtures, ensuring long-term performance.

CivilEng doi: 10.3390/civileng6020016

Authors: Narek Galustanian Mohamed T. Elshazli Harpreet Kaur Alaa Elsisi Sarah Orton

The construction of highway bridges using continuous precast prestressed concrete girders provides an economical solution by minimizing formwork requirements and accelerating construction. Different ways can be used to integrate bridge continuity and enable the development of negative bending moments at piers. Continuous bridge connections enhance structural integrity by reducing deflections and distributing loads more efficiently. Research has led to the development of various continuity details, categorized into partial and full integration, to improve performance under diverse loading conditions. This review summarizes studies on both partial and fully integrated continuous bridges, highlighting improvements in connection resilience and the incorporation of advanced construction technologies. While extended deck reinforcement presents an economical solution for partial continuity, it has limitations, especially in longer spans. However, full integration provides additional benefits, such as further reduced deflections and bending moments, contributing to improved overall structural performance. Positive-moment connections using bent bars have shown enhanced performance in achieving continuity, though skewed bridge configurations may reduce the effectiveness of continuity. Ultra-High-Performance Concrete (UHPC) has been identified as a superior material for joint connections, providing greater load capacity, durability, and seismic resistance. Additionally, mechanical splices, such as threaded rod systems, have proven effective in achieving continuity across various load types. The seismic performance of precast prestressed concrete girders relies on robust joint connections, particularly at column–foundation and column–cap points, where reinforcements such as steel plates, fiber-reinforced shells, and unbonded post-tensioning are important for shear and compression transfer.

CivilEng doi: 10.3390/civileng6010015

Authors: Amirhossein Javaherikhah Hadi Sarvari

Airport facility management requires innovative and coordinated techniques due to the infrastructure’s complexity, stakeholders’ diversity, and the necessity of safety. Adopting building information management (BIM) as an advanced technology has several benefits, including increased productivity, lower cost, and higher quality of service. This study seeks to determine the strategies for using BIM in airport facility management. In this vein, two questionnaires were developed to collect data based on a literature review. The first questionnaire was used to collect data for identifying and ranking the main criteria, and the second questionnaire was used to identify the practical strategies. The experts of this study answered five strengths, four weaknesses, five opportunities, and five threats using a standardized questionnaire. An integrated AHP-SWOT approach was used to identify and examine the practical strategies. Furthermore, a sensitivity analysis was used to ensure the results were correct. The findings showed that smart maintenance management, with a weight of 0.363, was the most important strength in the SWOT analysis. Resistance to change was the most important weakness, with a weight of 0.455. The increasing need for smart airports with a weight of 0.358 was the most important opportunity, while cybersecurity issues with a weight of 0.385 were the most important threat. Integrating BIM into the aviation sector can enhance efficiency and sustainability in airport facility management while addressing potential opportunities and shared hazards that extend beyond airport operations.

CivilEng doi: 10.3390/civileng6010014

Authors: Yasin Mumtaz Tetsuhiro Shimozato Nitta Kenta Matsui Naoki

Corrosion in steel girder ends, progressing from localized thinning of the web and the lower flange to severe perforation in severe cases, can significantly affect structural integrity. This study evaluates the effects of severe corrosion, including web–lower flange disconnection and transverse flange perforation combined with web damage, on the residual shear strength of steel girder end web panels through experimental and numerical methods. Results indicate that when only the web is affected, post-buckling strength starts to decline by corrosion damaging the plastic hinge on the tension flange, disrupting the tension field action. Conversely, in cases involving simultaneous web and lower flange damage, localized yielding at fracture points near the flange damage leads to the abrupt rotation of the tension field inclination angle, causing an earlier and more pronounced decline in post-buckling strength compared to web-only damage scenarios.

CivilEng doi: 10.3390/civileng6010013

Authors: Maria Anna De Rosa Isaac Elishakoff Maria Lippiello

Shells are significant structural components that are extensively utilized in numerous engineering fields, including architectural and infrastructural projects. These components are employed in the construction of domes, water tanks, stadiums and auditoriums, hangars, and cooling towers. Significant research efforts have been dedicated to the analysis of vibrations and dynamic behaviors of shells, due to their distinctive capacity to efficiently bear loads through their geometry rather than mass. Additionally, a vast array of shell theories and computational methods have been proposed and developed by researchers. This paper represents a continuation of research initiated begun in a 2009 paper by Elishakoff, wherein the suggestion was made to disregard an energetic term in the dynamic analysis of Timoshenko–Ehrenfest beams, wherein the suggestion was made to disregard an energetic term in the dynamic analysis of Timoshenko–Ehrenfest beams. The resulting reduced theory was found to be both more straightforward and more reliable than the complete, classical approach. While the original idea was heuristically justified, a more sound variationally consistent theory was proposed in the papers of De Rosa et al. concerning the dynamic analysis of the Timoshenko-Ehrenfest beams and later extended to the case of the Uflyand-Mindlin plates. In accordance with the proposal put forth in those works, we initially delineate the classical shell theory and subsequently propose two alternative hypotheses that give rise to two distinct aspects of the energy terms. By employing the variational approach, we derive two novel boundary problems, which are direct generalizations of those previously considered. Both theories can be readily specialized for beams and plates, and the theory can also be specialized for the case of cylindrical shells.

CivilEng doi: 10.3390/civileng6010012

Authors: Hossein Khosravi Mahmood Reza Toloue-Hassanpour Mojtaba Lezgy-Nazargah

The rapid progression in concrete technology and the emphasis on improving the mechanical characteristics and durability of concrete, as well as the need for skilled workers, were key factors that led to the fabrication of self-consolidating concrete (SCC). The primary advantage of SCC is the elimination of vibrations during construction. This experimental study investigates the effect of nano-silica, nano-clay, and micro-silica with ratios of 2% and 4% on the properties of SCC. To reach this aim, rheological tests (flow slump, V-shape funnel, U-shaped box, and L-shaped box tests), mechanical tests (compressive strength, tensile strength, and flexural strength test), and durability tests (freezing, abrasion, and permeability tests) were carried out. The results demonstrated that the mechanical characteristics and durability of the concrete were enhanced by increasing the nano-silica content up to 4% of the cement weight. Also, the increase in the nano-clay content produced suitable results for SCC in terms of mechanical and durability aspects. However, as the nano-material ratio increases, the amount of superplasticizer also increased to ensure the proper workability of the SCC.

CivilEng doi: 10.3390/civileng6010011

Authors: Atsushi Takao Nobuyoshi Yabuki Yoshikazu Otsuka Takashi Hirai

The productivity of the construction industry is about half that of the manufacturing industry, and the labor shortage in the construction industry is serious; therefore, improving productivity using information and communication technology (ICT) is an urgent issue. In addition, in civil engineering works, the number of projects that handle multiple types of soil and sand is increasing due to the recycling of construction waste soil; thus, traceability management is important to ensure quality. This paper presents a system that uses sensing on soil-transporting dump trucks and ICT to record which soil was piled up where with the aim of improving the efficiency of traceability management in earthwork construction. This system automatically creates traceability data by linking sensing data and data from the compaction management system via an application. This eliminates the need to record and manage the earthwork location, which was previously required manually to create traceability data, and reduces the labor and manpower required for traceability management. The created traceability data are automatically assigned attribute information such as the construction date and soil information; consequently, they can be used to check the construction history in the future.

CivilEng doi: 10.3390/civileng6010010

Authors: Johannes Solass Silvin Schapfel Alexander Stolz

The employment of automated non-destructive testing (NDT) methods for crack characterization in concrete, needs calibration and benchmarking in a controlled environment. This requires test specimen with comparable and ideally reproducible cracks. To this end, in this paper a method is presented that aims to mimic cracked concrete specimens with a high degree of control over the resulting crack parameters width, depth and length for material testing and calibration of automated (NDT) methods. The method comprises 3D-printing of formwork with integrated crack patterns. The obtained crack width accuracy is tested by comparing printed cracks and resulting cracks in the concrete with the desired width from the print file. This procedure enables the realization of crack widths ≥ 0.2 mm with a deviation in the range of 25% between desired and resulting crack width. Further, the proposed methodology is independent of intrinsic material properties which enables this accuracy.

CivilEng doi: 10.3390/civileng6010009

Authors: Joeel Bolaño Joyce De la Iglesia Michel Murillo Daniel Abudinen Fausto A. Canales Heidis Cano

Currently, the demand for environmental sustainability options in the construction industry is increasing, especially those related to the correct use of water. The aim of this work is to study different sustainable alternatives that minimize the use of water in cured hydraulic concrete, analyzing the effect of curing on hydration, microstructure, and compressive strength of hydraulic concrete exposed to different curing techniques: Manual Curing, Standard Curing, Vinipel, and Uncured. An experimental study was conducted using 180 cylindrical hydraulic concrete specimens, which were compression-tested at 7, 28, and 56 days. A Scanning Electron Microscope equipped with an Energy Dispersive X-ray Spectrometer analysis was carried out to examine the microstructural and compositional changes under the different curing techniques. The results indicate that the Vinipel technique is the best alternative, showing a compressive strength of 35 MPa after 56 days of curing. In general, Vinipel > Standard Curing > Manual Curing > Uncured is the order of strength from highest to lowest. The formation of hydration products was observed in all curing techniques. The presence of ettringite, complementing by abundant portlandite in Vinipel, shows the dominance of an important product in the strength of concrete. The best strength capacity under load and the lowest percentages of vacuum are likely to be favorable for the durability of the processes.

CivilEng doi: 10.3390/civileng6010008

Authors: Walter Avila-Ruiz Carlos Salazar-Briones José Mizael Ruiz-Gibert Marcelo A. Lomelí-Banda Juan Alejandro Saiz-Rodríguez

Topographical data are essential for hydrological analysis and can be gathered through on-site surveys, UAVs, or remote sensing methods such as Digital Elevation Models (DEMs). These tools are crucial in hydrological studies for accurately modeling basin morphology and surface stream network patterns. Two different DEMs with resolutions of 0.13 m and 5 m were used, as well as tools which carry out urban basin delineation by analyzing their morphometric parameters to process the hydrography of the study area, using three Geographic Information Systems (GIS): ArcGIS, GlobalMapper, and SAGA GIS. Each piece of software uses different algorithms for the pre-processing of DEMs in the calculation of morphometric parameters of the study area. The results showed variations in the quantity of delineated stream networks between the different GIS tools used, even when using the same DEM. Similarly, the morphometric parameters varied between GIS tools and DEMs, which tells us that the tools and topographic data used are important. The stream network generated using ArcGIS and the DEM obtained with UAV offered a more precise description of surface flow behavior in the study area. Concerning ArcGIS, it can be observed that between the resolutions of the INEGI DEM and the UAV DEM, the delimited area of micro-basin 1 presented a minimum difference of 0.03 km2. In contrast, micro-basin 2 had a more significant difference of 0.16 km2. These discrepancies in results are attributed to the different algorithms used by each piece of software and the resolution of each DEM. Although some studies claim to have obtained the same results using different software and algorithms, in this research, different results were obtained, and emphasize the importance of establishing procedural standards, as they can significantly impact the design of stormwater drainage systems. These comparisons will allow decision-makers to consider these aspects to standardize the tools and topographic data used in urban hydrological analyses.

CivilEng doi: 10.3390/civileng6010007

Authors: Bruno Villoria Sudath C. Siriwardane Jasna Bogunovic Jakobsen

Rib–deck (RD) welded joints in orthotropic steel bridge decks are prone to different fatigue crack mechanisms. Standard fatigue design methods are inadequate for some of these mechanisms under multiaxial non-proportional loading conditions. This study presents a framework to assess fatigue damage at RD welded joints, considering the different crack mechanisms based on the equivalent structural stress method and its extension to multiaxial non-proportional fatigue, which is the path-dependent maximum stress range (PDMR) cycle counting algorithm. The method is validated for uniaxial loading by using experimental data from the literature. Additionally, non-proportional fatigue damage at RD welded joints of a suspension bridge girder is investigated under simulated random traffic loading. The analyses reveal the limitations of the nominal stress approach to account for complex stress field variations. The PDMR method, more suited to capture the stress path dependency of non-proportional fatigue damage than the hot spot and critical plane-based methods, predicts higher fatigue damage. A comprehensive fatigue test campaign of full-scale RD welded joints is necessary to better understand their fatigue behaviour under multiaxial loading. Until more experimental data are available, the PDMR method is recommended for fatigue verifications of welded RD joints as it yields safer predictions.

CivilEng doi: 10.3390/civileng6010006

Authors: Gayatri Thakre Vinayak Kaushal Mohammad Najafi

Hail causes damage to property, including roofs, automobiles, and crops, with an average annual loss of USD 850 million. In residential structures in the southern U.S., tile roofing systems are common due to their resistance to the impact of hail and their long service life. Commercial low-slope roof systems are equally prone to hail-strike damages as steep residential roof systems. The objective of this paper is to present a literature review, inspection protocol, and case studies on a comparative assessment of the hail threshold for built-up roof (BUR) and tile roof (TR) systems. More than 90 published papers determining the hail impact assessment of different roofing systems from 1969 through 2024 were studied and analyzed. This study develops a comparative hail damage assessment study between BUR and TR systems and provides detailed statistical data and hail thresholds for various built-up roof composition systems. In addition, the different failure modes and their causes, the characteristics of hail impacts, and the variables influencing the impact resistance of these roofing systems were examined using field studies. To better understand the effects, it is recommended that an intelligent model be developed to predict the hail resistance threshold of various configurations of BUR and TR systems with critical variables.

CivilEng doi: 10.3390/civileng6010005

Authors: Ihab Gheni Hussien Zahraa Saeed Rasheed Parsa Asaadsamani Hadi Sarvari

Building information modelling (BIM) is an emerging technology in the building sector. As with any emerging technology, the identification of critical success factors (CSFs) for BIM is essential. On the other hand, small- and medium-sized enterprises (SMEs) consistently play a vital role in the construction industry. Therefore, it is essential to determine the critical success elements for the effective implementation of BIM in these companies. Hence, this study aims to determine the CSFs for implementing BIM in SMEs in the developing country of Iran. To accomplish this, three rounds of the Delphi technique were carried out with the participation of fifteen BIM professionals from SMEs based in Iran. According to the Delphi survey findings, a total of 27 CSFs were identified for the effective utilisation of BIM in SMEs. Subsequently, to assess the CSFs, a questionnaire utilising a five-point Likert scale measurement was designed. Then, it was distributed among specialists in construction SMEs in Iran. The questionnaire included twenty-seven factors categorised into four primary groups: technical, managerial, financial, and legal. A total of 56 questionnaires were gathered and examined. The findings indicate that the CSFs highlighted for implementing BIM in SMEs are above the average level. Furthermore, the CSFs with a high impact on successful BIM implementation in construction SMEs in Iran were determined. Four high-impact CSFs are (1) the employer’s demand; (2) understanding the advantages and practicality of implementing BIM; (3) awareness of and ensuring a return on investment; and (4) efficient and suitable legislation. The findings of this study can serve as a valuable resource for stakeholders, providing them with a useful tool to enhance decision-making about the implementation of BIM in SMEs, especially in developing countries.

CivilEng doi: 10.3390/civileng6010004

Authors: Alireza Roshan Magdy Abdelrahman

High Friction Surface Treatments (HFST) are recognized for their effectiveness in enhancing skid resistance and reducing road accidents. While Epoxy-based HFSTs are widely applied, they present limitations such as compatibility issues with existing pavements, high installation and removal costs, and durability concerns tied to substrate quality. As an alternative to traditional Epoxy-based HFSTs, this study investigated the effects of aggregate gradation as designated by agencies on the performance of asphalt-based HFST. Various aggregate types were assessed to evaluate friction performance and the impact of polishing cycles on non-Epoxy HFST. It was found that adjustments in aggregate size and gradation may be necessary when transitioning to asphalt-based HFSTs, given the different nature of asphalt as more temperature susceptible compared to Epoxy. Various asphalt binder grades were considered in this study. A series of tests, including the British Pendulum Test (BPT), Dynamic Friction Tester (DFT), Circular Track Meter (CTM), Micro-Deval (MD), and Aggregate Imaging Measurement System (AIMS), were conducted to measure Coefficient of Friction (COF), Mean Profile Depth (MPD), texture, and angularity before and after polishing cycles. The results showed that the COF in asphalt-based slabs decreased more significantly than in Epoxy-based slabs as polishing cycles increased for HFST and medium gradations. However, in coarse gradation, the COF of slabs using asphalt-based binder matched or even surpassed that of Epoxy after polishing. Notably, the PG88-16 binder for Calcined Bauxite (CB) had the smallest reduction in COF after 140K polishing cycles, with only a 19% decrease compared to a 23% reduction for Epoxy.

CivilEng doi: 10.3390/civileng6010003

Authors: Neda Godarzi Farzad Hejazi

Given that numerous countries are located near active fault zones, this review paper assesses the seismic structural functionality of buildings subjected to dynamic loads. Earthquake-prone countries have implemented structural health monitoring (SHM) systems on base-isolated structures, focusing on modal parameters such as frequencies, mode shapes, and damping ratios related to isolation systems. However, many studies have investigated the dissipating energy capacity of isolation systems, particularly rubber bearings with different damping ratios, and demonstrated that changes in these parameters affect the seismic performance of structures. The main objective of this review is to evaluate the performance of damage detection computational tools and examine the impact of damage on structural functionality. This literature review’s strength lies in its comprehensive coverage of prominent studies on SHM and model updating for structures equipped with dampers. This is crucial for enhancing the safety and resilience of structures, particularly in mitigating dynamic loads like seismic forces. By consolidating key research findings, this review identifies technological advancements, best practices, and gaps in knowledge, enabling future innovation in structural health monitoring and design optimization. Various identification techniques, including modal analysis, model updating, non-destructive testing (NDT), and SHM, have been employed to extract modal parameters. The review highlights the most operational methods, such as Frequency Domain Decomposition (FDD) and Stochastic Subspace Identification (SSI). The review also summarizes damage identification methodologies for base-isolated systems, providing useful insights into the development of robust, trustworthy, and effective techniques for both researchers and engineers. Additionally, the review highlights the evolution of SHM and model updating techniques, distinguishing groundbreaking advancements from established methods. This distinction clarifies the trajectory of innovation while addressing the limitations of traditional techniques. Ultimately, the review promotes innovative solutions that enhance accuracy, reliability, and adaptability in modern engineering practices.

CivilEng doi: 10.3390/civileng6010002

Authors: Sanduni Jayasinghe Mojtaba Mahmoodian Azadeh Alavi Amir Sidiq Zhiyan Sun Farham Shahrivar Sujeeva Setunge John Thangarajah

The concept of digital twins (DT)s enhances traditional structural health monitoring (SHM) by integrating real-time data with digital models for predictive maintenance and decision-making whilst combined with finite element modelling (FEM). However, the computational demand of FE modelling necessitates surrogate models for real-time performance, alongside the requirement of inverse structural analysis to infer overall behaviour via the measured structural response of a structure. A FEM-based machine learning (ML) model is an ideal option in this context, as it can be trained to perform those calculations instantly based on FE-based training data. However, the performance of the surrogate model depends on the ML model architecture. In this light, the current study investigates three distinct ML models to surrogate FE modelling for DTs. It was identified that all models demonstrated a strong performance, with the tree-based models outperforming the performance of the neural network (NN) model. The highest accuracy of the surrogate model was identified in the random forest (RF) model with an error of 0.000350, whilst the lowest inference time was observed with the trained XGBoost algorithm, which was at approximately 1 millisecond. By leveraging the capabilities of ML, FEM, and DTs, this study presents an ideal solution for implementing real-time DTs to advance the functionalities of current SHM systems.