CivilEng

Outrigger systems incorporating buckling-restrained braces (BRBs) can improve the seismic performance and resilience of tall buildings by combining lateral stiffness enhancement with supplemental energy dissipation. However, determining the effective number, elevation, and stiffness distribution of outrigger–BRBs remains computationally demanding when many possible configurations are considered. This study proposes a computationally efficient power-based sequential optimization approach for identifying effective outrigger–BRB placement and stiffness allocation in tall building systems. A nine-zone finite element benchmark model, developed in MATLAB based on a previously tested structural configuration, is used to examine the proposed method through nonlinear time-history analysis under the 1940 El Centro ground motion. The optimization procedure incrementally allocates BRB stiffness to candidate outrigger locations and selects the configuration that minimizes the maximum inter-story drift ratio at each step. The results are compared with a complete combinational reference search within the selected candidate space to assess whether the proposed procedure can identify optimal or near-optimal configurations with fewer nonlinear analyses. The findings show that the proposed method can reproduce the main effective outrigger–BRB placement patterns while reducing the number of required analyses within the investigated benchmark problem. The results also indicate that BRB stiffness limits influence the distribution of stiffness along the building height and promote more gradual drift reduction. Although the numerical investigation is limited to a benchmark model and a single seismic input, the proposed framework provides a practical basis for preliminary design, rapid parametric assessment, and future extension to multi-record and multi-objective optimization of outrigger–BRB systems. Full article

Microencapsulated phase change material (MPCM) can be used in place of sand in mortar to obtain phase change construction materials; however, this will degrade the mortar’s mechanical qualities. To address this challenge, a novel synergistic approach was proposed: phase change materials were used in mortar to enhance its thermal properties, while polyvinyl alcohol (PVA) fibers were uniquely incorporated to counteract the mechanical degradation caused by MPCM. Twenty different types of mortar were created and produced. Tests were conducted on the mortar’s micro properties, consistency, compressive strength, thermal conductivity, and specific heat capacity. The findings indicate that adding 0.4% PVA to the mortar optimally strengthened it, compensating for mechanical loss, while replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m⁻¹·K⁻¹, decreasing by up to 34.45% when the MPCM substitution rate reached 4%. Furthermore, as the MPCM substitution rate rises to 4%, the peak value of specific heat capacity increased by 195.28% during the heating process, and replacing sand with MPCM had a negative impact on consistency. The thermal conductivity of the PVA-MPCM mortar ranged from 0.75 to 1.2 W·m⁻¹·K⁻¹, indicating that adding MPCM to the mortar had a significant impact on thermal conductivity. As the MPCM substitution rate rises, so does the peak value of specific heat capacity. Full article

The Federal Institute of Material Research and Testing has performed many impact tests, from very small laboratory tests to very big “free-field” tests with heavy containers on stiff foundations. The first measurements have been done on a big foundation where it should be guaranteed that the foundation is rigid and the container is tested properly. Later, a smaller drop-test facility has been built on the ground inside an existing building. It had to be controlled by prediction and measurements to ensure that the drop test will not damage the building. Tests from different heights on soft, medium, and stiff targets have been done to find out rules which allow to identify acceptable and unacceptable drop tests. Later, the biggest drop test facility has been built for masses up to 200 t. It was necessary for the design of the foundation to estimate the forces which occur during the drop tests. In addition, the acceptable tests should be selected and controlled by measurements where the impact duration is important. Different sensors, accelerometers, accelerometers with mechanical filters, geophones (velocity transducers), strain gauges, and pressure cells have been applied for these tasks. Signal transformations and model calculations have been used to check and understand the dynamic measurements. The simplest law is the conservation of the momentum which is a good approximation if the impact is short. If the soil under the foundation has an influence on the deceleration of the container, the maximum foundation velocity is lower than the simple estimation. Full article

The present study investigates the application of conventional and ensemble machine learning models for slope stability prediction, which is essential for landslide risk reduction and sustainable infrastructure management. A database containing 627 slope cases was used, including six input variables: unit weight, cohesion, friction angle, slope angle, slope height, and pore pressure ratio. Six machine learning models, namely Extreme Gradient Boosting (XGBoost), Support Vector Machine (SVM), Random Forest (RF), K-Nearest Neighbors (KNN), Classification and Regression Tree (CART), and Boosted Tree, were developed and evaluated. The models were assessed using ROC analysis, confusion-matrix-derived metrics, precision–recall analysis, feature importance assessment, and unseen testing cases. The results showed that ensemble-based models provided superior predictive performance compared with conventional machine learning models. Based on ROC analysis, RF achieved the highest ROC-AUC value of 0.93, followed by Boosted Tree and XGBoost with ROC-AUC values of 0.92 and 0.90, respectively. Based on confusion-matrix-derived metrics, Boosted Tree achieved the highest accuracy of 0.862 and F1-score of 0.874, while RF showed comparable performance with an accuracy of 0.857 and F1-score of 0.868. Feature importance analysis indicated that cohesion and unit weight were among the most influential variables affecting slope stability prediction. In addition, the unseen testing cases confirmed the practical generalization capability of the ensemble models, with Boosted Tree and RF achieving accuracies of 0.920 and 0.880, respectively. Overall, the findings demonstrate that ensemble learning models, particularly Boosted Tree and RF, can provide reliable and interpretable decision-support tools for preliminary slope stability assessment and landslide hazard management. Full article

The decarbonization of the Architecture, Engineering, Construction, and Operation (AECO) sector has increased the need to incorporate carbon metrics into design decision-making. This article presents a Systematic Literature Review (SLR), based on the PRISMA protocol, to investigate whether the automation of CO₂ emission calculation combined with artificial intelligence has been used to support lower-impact design decisions in BIM-based building design. Searches were conducted in the Scopus, Web of Science, and ScienceDirect databases, considering articles published between 2021 and 2025, resulting in 2567 records. After duplicate removal and successive screening stages, 85 studies composed the final sample, classified into Core studies (BIM + CO₂ + AI) and Base studies (BIM + AI, BIM + CO₂, BIM + AI + Sustainability, and AI + CO₂). The results indicate the predominance of partial integrations and limited representation of Core studies. Although 60% of the studies quantify carbon, only 39% use this quantification to propose, compare, or optimize design alternatives. The findings suggest that BIM + CO₂ + AI integration has potential to support low-carbon building design but still requires greater standardization, interoperability, validation, traceability, and operational integration. Full article

This study presents the nonlinear seismic analysis of a large-scale suspension bridge under multiple sequential earthquake records. A detailed 3D finite element model is developed in SAP2000, incorporating CFST pylons, a composite deck, and a main cable suspension system. The novelty of this work lies in the combined treatment of two critical and often independently studied factors: nonlinear pile foundation behavior and sequential seismic loading. A Winkler-based nonlinear pile foundation model is established through depth-dependent p-y, t-z, and Q-z nonlinear spring curves implemented as Multi-Linear Plastic Link elements, capturing the full nonlinear lateral and axial response of the 1.8 m diameter, 60 m long pile group. Simultaneously, the structural response is evaluated under real seismic sequences rather than single events, addressing the cumulative damage that conventional analyses systematically underestimate. The results demonstrate that the combination of foundation nonlinearity and repeated seismic loading significantly amplifies internal forces and deformation demands on critical structural components, highlighting the inadequacy of standard single-event, fixed-base design assumptions for long-span bridges. Full article

High rock temperature (HRT) and its associated thermal hazards, alongside secondary mechanical risks such as swelling pressures induced in clay layers, pose severe threats to the construction safety of deep-buried tunnels. This study aims to quantitatively reveal the evolution laws of the surrounding rock temperature field under varying heat source conditions. A combined approach of physical model testing and numerical analysis was adopted. Utilizing an independently developed test system with a 1:13 geometric similarity ratio, the coupled rock-heat-ventilation environment was simulated. A transient conduction-convection 3D numerical model was established in COMSOL and verified against experimental data under benchmark conditions. The research confirms that under the influence of localized block heat sources, the temperature field in the far-field region follows a significant linear attenuation law rather than the traditional exponential distribution, with a prototype-equivalent gradient of approximately 0.69 °C/m. Furthermore, the study quantitatively identifies 8 m³ as the critical volume for heat source geometric saturation, beyond which the incremental temperature rise efficiency decreases by 25%. It is further revealed that the effective cooling depth of conventional ventilation is only approximately 0.35 m, indicating a significant “ventilation shielding effect” within the deep surrounding rock. Full article

Localized water infiltration in rock masses can significantly compromise the stability of foundations and underground structures. Conventional assessments often rely on average water content, while overlooking the spatial heterogeneity of water distribution. This study investigates the mechanical behavior and failure characteristics of black sandstone under partial water immersion through uniaxial compression tests at varying immersion depths and angles. The results indicate that partial immersion causes a sharp, nonlinear reduction in uniaxial compressive strength (UCS), with strength loss at 38.9% saturation reaching 88.5% of total failure, highlighting the vulnerability of partially wetted rock supporting building foundations. Wet–dry interfaces induce stiffness mismatch and stress concentration, shifting failure from global shear to localized lateral crushing, which may affect structural stability in underground or slope-adjacent buildings. Moreover, immersion angle governs a slight U-shaped evolution in strength, with the lowest strength at 45° and a limited recovery at 90°, suggesting orientation-dependent risks for inclined foundation beds. These findings demonstrate that spatial water distribution, rather than overall water content, is a primary factor in rock instability, providing a theoretical basis for risk assessment and design considerations in building and underground construction where localized wetting may occur. Full article

Hemp–lime composites are bio-based building materials with carbon sequestration potential, yet their properties exhibit significant variability depending on manufacturing variables, and standardized production guidelines remain lacking. This study investigates the influence of water-to-binder ratio (W/B = 1.75, 1.95, 2.15) and compaction degree (CD = 150%, 170%, 190%) on the thermal conductivity and compressive strength of hemp–lime composites using a full 3 × 3 factorial design at a binder-to-shiv ratio of B/S = 1:1. Results were synthesized with previously published investigations from a systematic research programme, enabling a comparative assessment of four technological variables across an extended dataset spanning densities from 227 to 518 kg/m³. The binder-to-shiv ratio was identified as the dominant factor governing both properties, primarily through its effect on bulk density and the mechanical character of the composite. Compaction degree was the most effective parameter for adjusting properties within a fixed mix design, with the strongest gains observed at the transition from CD = 150% to CD = 170%. The water-to-binder ratio exerted only marginal influence on bulk density and thermal conductivity, while its effect on compressive strength remained inconclusive at B/S = 1:1. Hemp shive particle size had a limited effect on thermal conductivity and no detectable influence on compressive strength. Both properties exhibited strong positive linear relationships with bulk density across the extended dataset. The findings support the standardization of hemp–lime composite production and the development of practical design guidelines. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article

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. Full article