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Infrastructures
Volume 10
Issue 9
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Infrastructures, Volume 10, Issue 9 (September 2025) – 32 articles

Cover Story (view full-size image): This paper analyzes the long-term thermal effect of fiber-reinforced concrete link slabs on an existing steel bridge for a rehabilitation project of the Maryland Transportation Authority. To accommodate the global thermal expansion of a full bridge, the existing fixed bearings were modified to expansion bearings to release the longitudinal thermal movement of the super-structure. Their movements were measured by the installed LVDT devices. In this pilot study for the Maryland Transportation Authority, engineered cementitious composite (ECC) and ultra-high-performance concrete (UHPC) were selected as candidate materials for link slabs to replace traditional steel expansion joints. The novelty of the study is in comparing the performance of different materials side by side using embedded sensor measurements and numerical simulation. View this paper
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28 pages, 3682 KB  
Article
Development of an Integrated 3D Simulation Model for Metro-Induced Ground Vibrations
by Omrane Abdallah, Mohammed Hussein and Jamil Renno
Infrastructures 2025, 10(9), 253; https://doi.org/10.3390/infrastructures10090253 - 21 Sep 2025
Viewed by 264
Abstract
This paper introduces a novel 3D simulation framework that integrates the Pipe-in-Pipe (PiP) model with Finite Element Analysis (FEA) using Ansys Parametric Design Language (APDL). This framework is designed to incorporate a 3D building model directly, assessing ground-borne vibrations from metro tunnels and [...] Read more.
This paper introduces a novel 3D simulation framework that integrates the Pipe-in-Pipe (PiP) model with Finite Element Analysis (FEA) using Ansys Parametric Design Language (APDL). This framework is designed to incorporate a 3D building model directly, assessing ground-borne vibrations from metro tunnels and their impact on surrounding structures. The PiP model efficiently calculates displacement fields around tunnels in full-space, applying the resulting fictitious forces to the FEA model, which includes a directly coupled 3D building model. This integration allows for precise simulation of vibration propagation through soil into buildings. A comprehensive verification test confirmed the model’s accuracy and reliability, demonstrating that the hybrid PiP-FEA model achieves significant computational savings-approximately 40% in time and 65% in memory usage-compared to the traditional full 3D FEA model. The results exhibit strong agreement between the PiP-FEA and full FEA models across a frequency range of 1–250 Hz, with less than 1% deviation, highlighting the effectiveness of the PiP-FEA approach in capturing the dynamic behavior of ground-borne vibrations. Additionally, the methodology developed in this paper extends beyond the specific case study presented and shows potential for application to various urban vibration scenarios. While the current validation is limited to numerical comparisons, future work will incorporate field data to further support the framework’s applicability under real metro-induced vibration conditions. Full article
(This article belongs to the Section Infrastructures and Structural Engineering)
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70 pages, 4598 KB  
Review
Maintenance Budget Allocation Models of Existing Bridge Structures: Systematic Literature and Scientometric Reviews of the Last Three Decades
by Eslam Mohammed Abdelkader, Abobakr Al-Sakkaf, Kyrillos Ebrahim and Moaaz Elkabalawy
Infrastructures 2025, 10(9), 252; https://doi.org/10.3390/infrastructures10090252 - 20 Sep 2025
Viewed by 435
Abstract
Bridges play an increasingly indispensable role in endorsing the economic and social development of societies by linking highways and facilitating the mobility of people and goods. Concurrently, they are susceptible to high traffic volumes and an intricate service environment over their lifespans, resulting [...] Read more.
Bridges play an increasingly indispensable role in endorsing the economic and social development of societies by linking highways and facilitating the mobility of people and goods. Concurrently, they are susceptible to high traffic volumes and an intricate service environment over their lifespans, resulting in undergoing a progressive deterioration process. Hence, efficient measures of maintenance, repair, and rehabilitation planning are critical to boost the performance condition, safety, and structural integrity of bridges while evading less costly interventions. To this end, this research paper furnishes a mixed review method, comprising systematic literature and scientometric reviews, for the meticulous examination and analysis of the existing research work in relation with maintenance fund allocation models of bridges (BriMai_all). With that in mind, Scopus and Web of Science databases are harnessed collectively to retrieve peer-reviewed journal articles on the subject, culminating in 380 indexed journal articles over the study period (1990–2025). In this respect, VOSviewer and Bibliometrix R package are utilized to create a visualization network of the literature database, covering keyword co-occurrence analysis, country co-authorship analysis, institution co-authorship analysis, journal co-citation analysis, journal co-citation, core journal analysis, and temporal trends. Subsequently, a rigorous systematic literature review is rendered to synthesize the adopted tools and prominent trends of the relevant state of the art. Particularly, the conducted multi-dimensional review examines the six dominant methodical paradigms of bridge maintenance management: (1) multi-criteria decision making, (2) life cycle assessment, (3) digital twins, (4) inspection planning, (5) artificial intelligence, and (6) optimization. It can be argued that this research paper could assist asset managers with a practical guide and a protocol to plan maintenance expenditures and implement sustainable practices for bridges under deterioration. Full article
(This article belongs to the Special Issue Advances in Structural Health Monitoring and Industry 5.0 Innovations for Bridge Management and Conservation)
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18 pages, 6298 KB  
Article
Structural Characteristics and Damage Analysis of Beijing Wanning Bridge Under the Coupling Effect of Dynamic Traffic and Subway Vibrations
by Yuhua Zhu and Yingmei Guo
Infrastructures 2025, 10(9), 251; https://doi.org/10.3390/infrastructures10090251 - 19 Sep 2025
Viewed by 220
Abstract
The Wanning Bridge is a critical component of Beijing’s Central Axis World Heritage site and the only Yuan Dynasty heritage bridge in Beijing still in service. Investigating its structural response under complex traffic conditions is therefore essential for ensuring the longevity of this [...] Read more.
The Wanning Bridge is a critical component of Beijing’s Central Axis World Heritage site and the only Yuan Dynasty heritage bridge in Beijing still in service. Investigating its structural response under complex traffic conditions is therefore essential for ensuring the longevity of this ancient structure and the safety of the urban transport system. However, the application of traditional research methods, such as direct sampling, is often constrained by the cultural relic characteristics of heritage bridges. This study first conducted a macroscopic on-site survey to document its current appearance and global geometry. Subsequently, more accurate geometric and material parameters of the bridge were acquired through non-destructive testing techniques including 3D laser scanning, ground-penetrating radar, and ultrasonic testing. Subsequently, using a combined approach of experimental and numerical simulation, this study reveals key structural responses and damage conditions of the bridge through static, dynamic, and metro-induced vibration tests. Dynamic tests show a maximum deformation of 0.26 mm and a natural frequency of 10.547 Hz, indicating shear strain accumulation as the primary damage driver. Subway-induced vibrations are well within the safety limits for stone relics, and the structure’s current load-bearing capacity complies with Class-II highway standards. Full article
(This article belongs to the Section Infrastructures and Structural Engineering)
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17 pages, 8823 KB  
Article
Static Loading Tests and Finite Element Analysis of Phosphogypsum Steel Truss Concrete Slabs
by Ao Zhang, Lirong Sha and Juan Fang
Infrastructures 2025, 10(9), 250; https://doi.org/10.3390/infrastructures10090250 - 19 Sep 2025
Viewed by 178
Abstract
This study investigates the utilization of phosphogypsum (PG), an industrial byproduct, as a sustainable additive in reinforced truss concrete slabs to promote eco-friendly construction practices. Through static loading tests (monotonic/cyclic) under mixed boundary conditions (simply supported fixed), four slabs—including 2% PG-modified and ordinary [...] Read more.
This study investigates the utilization of phosphogypsum (PG), an industrial byproduct, as a sustainable additive in reinforced truss concrete slabs to promote eco-friendly construction practices. Through static loading tests (monotonic/cyclic) under mixed boundary conditions (simply supported fixed), four slabs—including 2% PG-modified and ordinary concrete—were evaluated for mechanical performance, stress strain response, deflection, and crack propagation. The results demonstrated that PG enhanced slabs achieved comparable strength to conventional counterparts while exhibiting superior structural integrity at failure, highlighting PG’s potential to reduce environmental waste without compromising performance. Finite element analysis (ABAQUS2023) closely aligned with experimental data (<5% error), validating the model’s reliability in predicting failure modes. The study underscores PG’s viability as a circular economy solution for green building materials, offering dual benefits of waste valorization and resource efficiency. These findings advance sustainable construction by providing actionable insights for integrating industrial byproducts into high-performance structural systems, aligning with global decarbonization goals. Full article
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23 pages, 56189 KB  
Article
Connecting Cities: Solving Optimal-Resource-Distribution Problem Using Critical Range Radius
by Jorge L. Perez-Ramos, Ana M. Herrera-Navarro and Hugo Jimenez-Hernandez
Infrastructures 2025, 10(9), 249; https://doi.org/10.3390/infrastructures10090249 - 18 Sep 2025
Viewed by 187
Abstract
Navigating and planning optimal paths for resource delivery algorithms poses significant physical and technical challenges in urban areas, primarily due to the limitations of existing infrastructure. As smart cities continue to develop, the importance of these algorithms becomes increasingly evident. The saturation of [...] Read more.
Navigating and planning optimal paths for resource delivery algorithms poses significant physical and technical challenges in urban areas, primarily due to the limitations of existing infrastructure. As smart cities continue to develop, the importance of these algorithms becomes increasingly evident. The saturation of current urban landscapes exacerbates the complexity of navigating essential resources. Navigating densely connected networks can be intricate and often requires substantial computational resources or additional algorithms, as it can easily transform into an NP problem. Unfortunately, there is a lack of explicit algorithms designed for navigating these networks, resulting in a dependence on heuristic approaches and previous network systems. This reliance can create computational challenges, as navigation in this context typically involves a combinatorial search space. Current advances in Morphological Mathematics (MM) help to model everyday tasks as processes in discrete spaces, which take advantage of the properties offered by the morphological operators. Morphological Shortest-Path-Planning (MSPP) is a recent solution that effectively calculates the optimal trajectory within complex graphs. By utilizing morphological operators, this approach takes into account discrete properties and maps the process as a complete implementation algorithm using integer logic. In larger cities, determining the optimal delivery route and time from a resource center is a common task. This process is influenced by factors such as average speed, travel time, and distance, which generate a complex graph representation of the town, complicating its analysis. This paper presents a strategy for computing and analyzing delivery times by determining the accessibility of reliable paths from a delivery center to potential destinations in dense urban areas. The strategy presented and the use of the MSPP approach are suitable for calculating the time spent delivering and the distance traveled in working journeys. The MSPP approach is found to be nearly 60% more efficient than the reference approach for computing the optimal path in the case study presented. Full article
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18 pages, 8827 KB  
Article
Evaluation of Connected Vehicle Pavement Roughness Data for Statewide Needs Assessment
by Andrew Thompson, Jairaj Desai and Darcy M. Bullock
Infrastructures 2025, 10(9), 248; https://doi.org/10.3390/infrastructures10090248 - 18 Sep 2025
Viewed by 290
Abstract
Many agencies use pavement condition assessments such as the Pavement Surface Evaluation and Rating (PASER) and Pavement Condition Index (PCI) to develop localized pavement management programs. However, both techniques involve some subjectivity and inconsistent measurement practices, making it difficult to scale uniformly across [...] Read more.
Many agencies use pavement condition assessments such as the Pavement Surface Evaluation and Rating (PASER) and Pavement Condition Index (PCI) to develop localized pavement management programs. However, both techniques involve some subjectivity and inconsistent measurement practices, making it difficult to scale uniformly across all 86 thousand miles of local agency roadway in Indiana’s 92 counties. International Roughness Index (IRI) data is one emerging data source that could address this need. This paper evaluates the feasibility of using Connected Vehicle-estimated IRI (IRICVe) data for long-term statewide pavement monitoring on local roads. The analysis is based on approximately 4.1 billion daily IRICVe records collected over a multi-year study period from connected vehicles operating throughout the state. A modular data processing workflow was developed to clean and process these records and is presented in detail in the paper. The study includes network-level condition comparisons, insights on spatiotemporal trends, and localized segment-level condition monitoring. In 2024, approximately 53% of paved local roads in Indiana had at least one IRICVe observation per year. Coverage varied widely by county: for example, 79% of roads in urban Hamilton County had coverage, but only 14% had coverage in rural Martin County. The findings in this study demonstrate the potential of IRICVe to support local agency pavement asset management by providing cost-effective data-driven insights in near real-time. Full article
(This article belongs to the Section Smart Infrastructures)
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22 pages, 5930 KB  
Article
A Computer Vision-Based Pedestrian Flow Management System for Footbridges and Its Applications
by Can Zhao, Yiyang Jiang and Jinfeng Wang
Infrastructures 2025, 10(9), 247; https://doi.org/10.3390/infrastructures10090247 - 17 Sep 2025
Viewed by 297
Abstract
Urban footbridges are critical infrastructure increasingly challenged by vibration issues induced by crowd activity. Real-time monitoring of pedestrian dynamics is essential for evaluating structural safety, ensuring pedestrian comfort, and enabling proactive management. This paper proposes a lightweight, fully automated computer vision system for [...] Read more.
Urban footbridges are critical infrastructure increasingly challenged by vibration issues induced by crowd activity. Real-time monitoring of pedestrian dynamics is essential for evaluating structural safety, ensuring pedestrian comfort, and enabling proactive management. This paper proposes a lightweight, fully automated computer vision system for real-time monitoring of crowd dynamics on footbridges. The system integrates object detection, multi-target tracking, and monocular depth estimation to precisely quantify key crowd metrics: pedestrian flow rate, density, and velocity. Experimental validation demonstrated high performance: Flow rate estimation achieved 92.7% accuracy; density estimation yielded a 2.05% average relative error; and velocity estimation showed an 8.7% average relative error. Furthermore, the system demonstrates practical utility by successfully categorizing pedestrian behaviors using velocity data and triggering timely warnings. Crucially, field tests confirmed a minimum error of 5.56% between bridge vibration simulations driven by the system’s captured crowd data and physically measured acceleration data. This high agreement validates the system’s capability to provide reliable inputs for structural assessment. The proposed system establishes a practical technological foundation for intelligent footbridge management, focusing on safety, comfort, and operational efficiency through real-time crowd insights and automated alerts. Full article
(This article belongs to the Topic Advances in Intelligent Construction, Operation and Maintenance, 2nd Edition)
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44 pages, 7055 KB  
Review
Towards Resilient Critical Infrastructure in the Face of Extreme Wildfire Events: Lessons and Policy Pathways from the US and EU
by Nikolaos Kalapodis, Georgios Sakkas, Danai Kazantzidou-Firtinidou, Fermín Alcasena, Monica Cardarilli, George Eftychidis, Cassie Koerner, Lori Moore-Merrell, Emilia Gugliandolo, Konstantinos Demestichas, Dionysios Kolaitis, Mohamed Eid, Vasiliki Varela, Claudia Berchtold, Kostas Kalabokidis, Olga Roussou, Krishna Chandramouli, Maria Pantazidou, Mike Cox and Anthony Schultz
Infrastructures 2025, 10(9), 246; https://doi.org/10.3390/infrastructures10090246 - 17 Sep 2025
Viewed by 602
Abstract
Escalating extreme wildfires, fueled by the confluence of climate change, land use patterns alterations, ignitions by humans, and flammable fuels accumulation, pose significant and increasingly destructive risks to critical infrastructure (CI). This study presents a comprehensive comparative analysis of wildfire impacts and the [...] Read more.
Escalating extreme wildfires, fueled by the confluence of climate change, land use patterns alterations, ignitions by humans, and flammable fuels accumulation, pose significant and increasingly destructive risks to critical infrastructure (CI). This study presents a comprehensive comparative analysis of wildfire impacts and the corresponding CI resilience strategies employed across the EU and the US. It examines the vulnerability of CIs to the devastating effects of wildfires and their inadvertent contribution to wildfire ignition and spread. The study evaluates the EU’s CER Directive and the US National Infrastructure Protection Plan and assesses European Commission wildfire resilience-related initiatives, including FIRELOGUE, FIRE-RES, SILVANUS, and TREEADS flagship projects. It synthesizes empirical evidence and extracts key lessons learned from major wildfire events in the EU (2017 Portuguese fires; 2018 Mati wildfire) and the US (2023 Lahaina disaster; 2025 Los Angeles fires), drawing insights regarding the effectiveness of various resilience measures and identifying areas for improvement. Persistent challenges impeding effective wildfire resilience are identified, including governance fragmentation, lack of standardization in risk assessment and mitigation protocols, and insufficient integration of scientific knowledge and data into policy formulation and implementation. It concludes with actionable recommendations aimed at fostering science-based, multi-stakeholder approaches to strengthen wildfire resilience at both policy and operational levels. Full article
(This article belongs to the Topic Disaster Risk Management and Resilience)
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30 pages, 1627 KB  
Article
Comparative Sustainability Assessment of Proprietary and Non-Proprietary Ultra-High Performance Concrete Mixtures
by Ali Alsalman, Lateef Assi, Kealy Carter, Mohammed A. Mousa, Canh N. Dang, W. Micah Hale and Ayad Al-Yousuf
Infrastructures 2025, 10(9), 245; https://doi.org/10.3390/infrastructures10090245 - 16 Sep 2025
Viewed by 460
Abstract
Ultra-high-performance concrete (UHPC) has greater strength and durability compared to traditional concrete. While these benefits are well established, there are differences in UHPC based on the constituent materials in the mixture. These variations impact the mixtures’ CO2 emissions, efficiency, and cost. Given [...] Read more.
Ultra-high-performance concrete (UHPC) has greater strength and durability compared to traditional concrete. While these benefits are well established, there are differences in UHPC based on the constituent materials in the mixture. These variations impact the mixtures’ CO2 emissions, efficiency, and cost. Given the contribution of concrete to overall greenhouse gas emissions, it is important to understand the potential impact of UHPC from an environmental standpoint. This study addresses the environmental and economic impact of UHPC by examining five proprietary and five non-proprietary mixtures. The investigation is guided by three research questions, as follows: (1) How do energy consumption, CO2 emissions, and cost compare between proprietary and non-proprietary UHPC mixtures? (2) Which materials are the most influential drivers of these sustainability metrics? (3) Can non-proprietary mixtures provide comparable or better performance in terms of sustainability? Using secondary data from the literature, we calculate and analyze the energy, emissions, and cost of each UHPC constituent. The results indicate that steel fibers account for 53% of the total energy of UHPC. Ordinary Portland cement (OPC) is responsible for 73% of total CO2 emissions. Aggregates, admixtures, and SCMs have a minimal impact on the energy and emissions of the selected mixtures. However, they can affect the cost significantly. To highlight the key findings, non-proprietary mixtures showed substantial sustainability advantages. For example, UHPC-1 achieved up to 65% lower energy consumption, 49% lower CO2 emissions, and 80% lower cost compared to proprietary mixtures. These results highlight the potential of non-proprietary UHPC to serve as an ecologically friendly and cost-effective substitute for infrastructure applications. Full article
(This article belongs to the Special Issue Advances in Reinforced Concrete Infrastructure: Enhancing Structural Resilience and Promoting Sustainability)
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17 pages, 2103 KB  
Article
Preparation and Performance Evaluation of a Low-Fume Asphalt Binder
by Hongmei Cai, Rui Li, Yuzhen Zhang and Junrui Xiao
Infrastructures 2025, 10(9), 244; https://doi.org/10.3390/infrastructures10090244 - 16 Sep 2025
Viewed by 221
Abstract
Asphalt fume emissions cause significant environmental hazards during the preparation of hot-mix asphalt. In this study, experimental investigations were conducted employing a reactor vessel to simulate asphalt fumes under controlled conditions. Asphalt fumes were obtained through an integrated system comprising glass fiber filter [...] Read more.
Asphalt fume emissions cause significant environmental hazards during the preparation of hot-mix asphalt. In this study, experimental investigations were conducted employing a reactor vessel to simulate asphalt fumes under controlled conditions. Asphalt fumes were obtained through an integrated system comprising glass fiber filter cartridges and an impinger absorption bottle. Quantitative analysis was then conducted using gravimetric analysis and UV-Vis spectrophotometry. Through systematic monitoring of compositional changes in asphalt binder fractions, the fume emission characteristics during in-plant mixing operations were quantitatively correlated with the following processing parameters: temperature, airflow rate, and mixing duration. Comparative evaluation revealed optimal performance from a ternary compound inhibitor containing cuprous chloride, ditert-butylhydroquinone, and ferric chloride in mass proportions of 4:4:2. At a critical dosage of 0.6 wt%, this compound inhibitor demonstrated significant reduction in total particulate matter emissions without compromising asphalt binder properties. In addition, comprehensive performance characterization through rheological testing and thin-film oven aging (TFOT) showed that the modified low-fume asphalt binder maintained equivalent or improved performances compared to a conventional asphalt binder. Full article
(This article belongs to the Topic Advancing Construction Safety and Health: Innovations and Strategies)
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19 pages, 3475 KB  
Article
Tree-Based Surrogate Model for Predicting Aerodynamic Coefficients of Iced Transmission Conductor Lines
by Guoliang Ye, Zhiguo Li, Anjun Wang, Zhiyi Liu, Ruomei Tang and Guizao Huang
Infrastructures 2025, 10(9), 243; https://doi.org/10.3390/infrastructures10090243 - 15 Sep 2025
Viewed by 227
Abstract
Ultra-high-voltage (UHV) transmission lines are prone to galloping and oscillations under ice and wind loads, posing risks to system reliability and safety. Accurate aerodynamic coefficients are essential for evaluating these effects, but conventional wind tunnel and CFD methods are costly and inefficient for [...] Read more.
Ultra-high-voltage (UHV) transmission lines are prone to galloping and oscillations under ice and wind loads, posing risks to system reliability and safety. Accurate aerodynamic coefficients are essential for evaluating these effects, but conventional wind tunnel and CFD methods are costly and inefficient for practical applications. To address these challenges, this study develops a surrogate model for rapid and accurate prediction of aerodynamic coefficients for six-bundle conductors. Initially, a CFD model to calculate the aerodynamic coefficients of six-bundle conductors was proposed and validated against wind tunnel experimental results. Subsequently, Latin hypercube sampling (LHS) was employed to generate datasets covering wind speed, icing shape, icing thickness, and wind attack angle. High-throughput numerical simulations established a comprehensive aerodynamic database used to train and validate multiple tree-based surrogate models, including decision tree (DT), random forest (RF), extremely randomized trees (ERTs), gradient boosted decision tree (GBDT), and extreme gradient boosting (XGBoost). Comparative analysis revealed that the XGBoost-based model achieved the highest prediction accuracy, with an R2 of 0.855 and superior generalization performance. Feature importance analysis further highlighted wind speed and icing shape as the dominant influencing factors. The results confirmed the XGBoost surrogate as the most effective among the tested models, providing a fast and reliable tool for aerodynamic prediction, vibration risk assessment, and structural optimization in UHV transmission systems. Full article
(This article belongs to the Section Infrastructures and Structural Engineering)
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25 pages, 2949 KB  
Article
Strategic Vertiport Placement for Airport Access: Utilizing Urban Air Mobility for Accelerated and Reliable Transportation
by Vasileios Volakakis and Hani S. Mahmassani
Infrastructures 2025, 10(9), 242; https://doi.org/10.3390/infrastructures10090242 - 14 Sep 2025
Viewed by 574
Abstract
Airport-bound access and egress trips comprise a significant portion of total ground transportation trips, especially in regions served by large airports. Connecting urban areas with airports under minimal travel delays can be challenging, with traffic congestion along busy connecting corridors being a common [...] Read more.
Airport-bound access and egress trips comprise a significant portion of total ground transportation trips, especially in regions served by large airports. Connecting urban areas with airports under minimal travel delays can be challenging, with traffic congestion along busy connecting corridors being a common phenomenon. Urban Air Mobility (UAM) is a new transportation mode envisioned to reduce travel times using specific aircraft, such as electric (and non-electric) Vertical or Short Take-off and Landing aircraft (e/VTOLs and STOLs, respectively). The operation of these aircraft requires take-off and landing infrastructure known as vertiports. A strategic infrastructure placement framework was introduced, utilizing and adapting the Capacitated Facility Location Problem (a-CFLP) and the Maximal Covering Location Problem (a-MCLP) with capacity constraints. An adapted capacitated k-means algorithm and a greedy heuristic were considered for the solution of the a-CFLP, while the a-MCLP was formulated as a mixed-integer linear programming problem. The proposed framework was applied in the Chicago Metropolitan Area, revealing that various trade-offs regarding coverage and accessibility, versus operational costs (number of facilities, facility capacity, and service radius), exist. The results showed that, depending on vertiport capacity and service radius capabilities, a range of 5 to 12 vertiports can sufficiently address the demand (above 95% demand coverage) and, with respect to accessibility, serve a moderate UAM demand scenario of 6124 daily requests, as identified for this region. Full article
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23 pages, 12001 KB  
Article
Sustainable High-Performance Geopolymer Concrete: The Role of Recycled Industrial Wastes in Strength, Durability, and Microstructure Enhancement
by Osama Youssf, Ahmed Mohamed Abbass, Ahmed K. Ahmed and Ahmed M. Tahwia
Infrastructures 2025, 10(9), 241; https://doi.org/10.3390/infrastructures10090241 - 12 Sep 2025
Viewed by 494
Abstract
High-performance geopolymer concrete (HPGC) is an eco-friendly type of concrete that is traditionally made of slag, silica fume (SF), and quartz sand. Recycling industrial waste in HPGC presents an eco-friendly approach for maximizing sustainability in the construction sector. This study evaluates the impact [...] Read more.
High-performance geopolymer concrete (HPGC) is an eco-friendly type of concrete that is traditionally made of slag, silica fume (SF), and quartz sand. Recycling industrial waste in HPGC presents an eco-friendly approach for maximizing sustainability in the construction sector. This study evaluates the impact of incorporating recycled fine aggregates like crumb rubber (CR), glass waste (GW), and ceramic waste (CW) as partial replacements for quartz sand in HPGC at 10%, 20%, and 40% by volume. GW and CW were also used in binder size as full replacements for SF. The novelty of this research lies in its comprehensive evaluation of waste-integrated HPGC under diverse conditions, including mechanical performance, durability (water absorption, sulfate/chloride/acid resistance), thermal stability (up to 600 °C), and microstructure analysis, while addressing critical gaps in eco-friendly construction materials. The results indicate that CW significantly enhanced compressive strength, increasing by 24–29% at 10% and 40% replacement levels, whereas CR reduced strength by 69.2–83.5%. GW effectively decreases water absorption by 66–72% compared to CW and CR. Both CW and GW improved chemical resistance, reducing compressive strength loss by 15–33% under sulfate and acid attacks. CW exhibited superior residual strength at 600 °C, reaching 96.4 MPa, compared to 54.5 MPa for GW. However, fully replacing SF with GW or CW as a binder resulted in performance deterioration, making it unsuitable. This study demonstrates that incorporating recycled waste materials in HPGC enhances its mechanical and durability properties, making it a viable option for sustainable construction. The findings support the integration of CW and GW as eco-friendly alternatives in HPGC applications. Full article
(This article belongs to the Special Issue Advances in Reinforced Concrete Infrastructure: Enhancing Structural Resilience and Promoting Sustainability)
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21 pages, 4521 KB  
Article
CCT Net: A Dam Surface Crack Segmentation Model Based on CNN and Transformer
by Hongzheng Ling and Futing Sun
Infrastructures 2025, 10(9), 240; https://doi.org/10.3390/infrastructures10090240 - 11 Sep 2025
Viewed by 319
Abstract
Concrete dams are essential components in hydraulic engineering, and the detection of surface cracks remains a major concern in structural health monitoring. This study presents CCT Net, a segmentation model designed to enable the automated detection and segmentation of dam surface cracks. By [...] Read more.
Concrete dams are essential components in hydraulic engineering, and the detection of surface cracks remains a major concern in structural health monitoring. This study presents CCT Net, a segmentation model designed to enable the automated detection and segmentation of dam surface cracks. By combining the strengths of convolutional neural networks (CNNs) and Transformers, the model improves the ability to capture fine crack features and global structural patterns, addressing the limitations of single-model approaches. The proposed Feature Complementary Fusion Module enables the effective integration of local and global features, contributing to enhanced segmentation accuracy. The experimental results show that CCT Net achieves high performance on the dam crack segmentation dataset, with the Precision, Recall, F1 score, and mean Intersection over Union (mIoU) reaching 94.5, 93.5, 94.0, and 88.7%, respectively. Compared with traditional CNN-based, Transformer-based, and other existing models, CCT Net demonstrates improved crack segmentation capability. Full article
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22 pages, 6537 KB  
Article
Dynamic Simulation and Seismic Analysis of Hillside RC Buildings Isolated by High-Damping Rubber Bearings
by Abdul Ghafar Wahab, Zhong Tao, Hexiao Li, Ahmad Yamin Rasa, Tabasum Huma and Yuming Liang
Infrastructures 2025, 10(9), 239; https://doi.org/10.3390/infrastructures10090239 - 10 Sep 2025
Viewed by 1436
Abstract
Hillside buildings are particularly vulnerable to earthquakes owing to their structural configuration; however, research addressing this issue remains limited. This study investigates the effectiveness of high-damping rubber bearings (HDRBs) in enhancing the seismic resilience of hillside structures. Five numerical models were analyzed using [...] Read more.
Hillside buildings are particularly vulnerable to earthquakes owing to their structural configuration; however, research addressing this issue remains limited. This study investigates the effectiveness of high-damping rubber bearings (HDRBs) in enhancing the seismic resilience of hillside structures. Five numerical models were analyzed using non-linear time-history (NTH) analysis, including two flat-plane structures (one isolated and one with a fixed base) and three dropped-layer structures on hillside terrain (one with base isolation, one with inter-story isolation, and one with a fixed base). Deformation history integral (DHI) modeling was employed to simulate the HDRBs. Six earthquake ground motions from the PEER database and one scaled from 0.2–0.8 g were used to assess the seismic responses of the buildings. The results indicate that HDRBs significantly improved the seismic performance. The flat-plane isolated system (FIS) model achieved a nearly 90% reduction in peak roof acceleration compared to fixed-base structures. The dropped-layer isolated system (DIS) and dropped-layer inter-story isolated system (DIIS) models exhibited reductions of approximately 80% in the peak roof acceleration. Furthermore, the isolated structures demonstrated up to 78% reduction in the maximum inter-story drift, along with significant decreases in the story shear forces and overturning moments. Compared with non-isolated dropped-layer structures, the DIS and DIIS models showed reductions of 70% and 55% in the base shear force, respectively. The results highlight the efficacy of HDRBs in energy dissipation and their significant role in enhancing the seismic resilience of mountain structures. Full article
(This article belongs to the Special Issue Advances in Structural Dynamics and Earthquake Engineering, Second Edition)
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13 pages, 2763 KB  
Article
Structural Deflection Measurement with a Single Smartphone Using a New Scale Factor Calibration Method
by Long Tian, Yangxiang Yuan, Liping Yu and Xinyue Zhang
Infrastructures 2025, 10(9), 238; https://doi.org/10.3390/infrastructures10090238 - 10 Sep 2025
Viewed by 301
Abstract
This study proposes a novel structural deflection measurement method using a single smartphone with an innovative scale factor (SF) calibration technique, eliminating reliance on laser rangefinders and industrial cameras. Conventional off-axis digital image correlation (DIC) techniques require laser rangefinders to measure discrete points [...] Read more.
This study proposes a novel structural deflection measurement method using a single smartphone with an innovative scale factor (SF) calibration technique, eliminating reliance on laser rangefinders and industrial cameras. Conventional off-axis digital image correlation (DIC) techniques require laser rangefinders to measure discrete points for SF calculation, suffering from high hardware costs and sunlight-induced ranging failures. The proposed approach replaces physical ranging by deriving SF through geometric relationships of known structural dimensions (e.g., bridge length/width) within the measured plane. A key innovation lies in developing a versatile SF calibration framework adaptable to varying numbers of reference dimensions: a non-optimized calculation integrates smartphone gyroscope-measured 3D angles when only one dimension is available; a local optimization model with angular parameters enhances accuracy for 2–3 known dimensions; and a global optimization model employing spatial constraints achieves precise SF resolution with ≥4 reference dimensions. Indoor experiments demonstrated sub-0.05 m ranging accuracy and deflection errors below 0.30 mm. Field validations on Beijing Subway Line 13′s bridge successfully captured dynamic load-induced deformations, confirming outdoor applicability. This smartphone-based method reduces costs compared to traditional setups while overcoming sunlight interference, establishing a hardware-adaptive solution for vision-based structural health monitoring. Full article
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13 pages, 1789 KB  
Article
Simulation of Pantograph–Catenary Arc Temperature Field in Urban Railway and Study of Influencing Factors on Arc Temperature
by Xiaoying Yu, Yang Su, Mengjie Song, Junrui Yang, Liying Song, Ze Wang, Yixiao Liu, Caizhuo Wei and Yongjia Cheng
Infrastructures 2025, 10(9), 237; https://doi.org/10.3390/infrastructures10090237 - 10 Sep 2025
Viewed by 246
Abstract
During the running of urban railway trains, arcs of the pantograph–catenary (PC) system cause instantaneous high-temperature ablation of PC system materials, which severely impact the standard running of trains. Utilizing magnetohydrodynamics (MHD), a mathematical model of urban railway PC arcs is introduced in [...] Read more.
During the running of urban railway trains, arcs of the pantograph–catenary (PC) system cause instantaneous high-temperature ablation of PC system materials, which severely impact the standard running of trains. Utilizing magnetohydrodynamics (MHD), a mathematical model of urban railway PC arcs is introduced in this article. The multiphysics finite element analysis platform COMSOL Multiphysics was used to solve and simulate the mathematical model of the PC arc. The simulation results were analyzed to explore the temperature dispersion law of the PC arc. Experimental measurements of arc duration and arc temperature were conducted, with the mathematical model’s accuracy validated through empirical comparisons. Based on the established mathematical model of the PC arc, the effects of PC gap and current intensity on the arc temperature were investigated. The results reveal that the PC arc’s temperature field follows a radially decaying dispersion, attaining maximum temperature in the center of the arc column. The surface temperature of the pantograph strip is higher than that of the contact wire. As the duration of the PC arc increases, the arc temperature gradually increases; the temperature of the PC arc diminishes with the increase in the PC gap. The PC current increases, and the arc zone temperature increases. The research conclusions of this article can provide a basis for mitigating the number of PC arcs and enhancing the quality of the PC current. Full article
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19 pages, 16857 KB  
Article
Mechanical Response Mechanism and Acoustic Emission Evolution Characteristics of Deep Porous Sandstone
by Zihao Li, Guangming Zhao, Xin Xu, Chongyan Liu, Wensong Xu and Shunjie Huang
Infrastructures 2025, 10(9), 236; https://doi.org/10.3390/infrastructures10090236 - 9 Sep 2025
Viewed by 309
Abstract
To investigate the failure mechanisms of surrounding rock in deep mine tunnels and its spatio-temporal evolution patterns, a true triaxial disturbance unloading rock testing system, the acoustic emission (AE) system, and the miniature camera monitoring system were employed to conduct true triaxial graded [...] Read more.
To investigate the failure mechanisms of surrounding rock in deep mine tunnels and its spatio-temporal evolution patterns, a true triaxial disturbance unloading rock testing system, the acoustic emission (AE) system, and the miniature camera monitoring system were employed to conduct true triaxial graded loading tests on sandstone containing circular holes at burial depths of 800 m, 1000 m, 1200 m, 1400 m, and 1600 m. The study investigated the patterns of mechanical properties and failure characteristics of porous sandstone at different burial depths. The results showed that the peak strength of the specimens increased quadratically with increasing burial depth; the failure process of porous sandstone could be divided into four stages: the calm period, the particle ejection period, the stable failure period, and the complete collapse period; as burial depth increases, the failure mode transitions from a composite tensile–shear crack type to a shear crack-dominated type, with the ratio of shear cracks to tensile cracks exhibiting quadratic growth and reduction, respectively; the particle ejection stage is characterised by low-frequency, low-amplitude signals, corresponding to the microcrack initiation stage, while the stable failure stage exhibits a sharp increase in low-frequency, high-amplitude signals, reflecting macrocrack propagation characteristics, with the spatial evolution of their locations ultimately forming a penetrating oblique shear failure zone; and peak stress analysis indicates that as burial depth increases, peak stress during the particle ejection phase first increases and then decreases, while peak stress during the stable failure phase first decreases and then stabilises. The duration of the pre-instability calm phase shows a significant negative correlation with burial depth. The research findings provide a theoretical basis for controlling tunnel rock mass stability and disaster warning. Full article
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18 pages, 3955 KB  
Article
Seismic Retrofitting of RC Frames Using Viscous Dampers: Numerical Simulation and Nonlinear Response Analysis
by Pengfei Ma and Shangke Yuan
Infrastructures 2025, 10(9), 235; https://doi.org/10.3390/infrastructures10090235 - 6 Sep 2025
Viewed by 491
Abstract
Reinforced concrete (RC) frame structures in high-seismicity regions often exhibit vulnerability under strong earthquakes, necessitating effective retrofitting solutions. This study evaluates viscous fluid dampers (VFDs) as a solution for seismic retrofitting of an existing four-story RC school building in China’s high-seismicity zone. Nonlinear [...] Read more.
Reinforced concrete (RC) frame structures in high-seismicity regions often exhibit vulnerability under strong earthquakes, necessitating effective retrofitting solutions. This study evaluates viscous fluid dampers (VFDs) as a solution for seismic retrofitting of an existing four-story RC school building in China’s high-seismicity zone. Nonlinear time-history analyses were conducted using ETABS under frequent earthquakes (FEs) and the maximum considered earthquake (MCE), comparing structural responses before and after retrofitting. The results demonstrate that VFDs reduced inter-story drift ratios by 10–40% (FEs) and 33–37% (MCE), ensuring compliance with code limits (1/50 under MCE). Base shear decreased by 34.6% (X-direction) and 32.3% (Y-direction), while dampers contributed 66.7% (X) and 40% (Y) of total energy dissipation under FEs, increasing to 74% (X) and 47% (Y) under the MCE. Additional damping ratios reached 3.3–3.7% (X) and 2.0–2.4% (Y), significantly mitigating plastic hinge formation. This study validates VFDs as a high-performance retrofitting solution for RC frames, offering superior energy dissipation compared to traditional methods. Full article
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24 pages, 4550 KB  
Article
Community-Scale Seismic Vulnerability Assessment of RC Churches: A Simplified Approach for Cultural Infrastructure Resilience
by Giuseppe Brandonisio and Muhammad Tayyab Naqash
Infrastructures 2025, 10(9), 234; https://doi.org/10.3390/infrastructures10090234 - 4 Sep 2025
Viewed by 305
Abstract
This study proposes a simplified, mechanics-based methodology for assessing the seismic vulnerability of reinforced concrete (RC) churches, particularly those with basilica plans and cathedral portal frames such as a repetitive inclined-beam portal frame. The method integrates linear and nonlinear static analyses, plastic limit [...] Read more.
This study proposes a simplified, mechanics-based methodology for assessing the seismic vulnerability of reinforced concrete (RC) churches, particularly those with basilica plans and cathedral portal frames such as a repetitive inclined-beam portal frame. The method integrates linear and nonlinear static analyses, plastic limit theory, and capacity spectrum methods to generate seismic risk indices using minimal input data, making it suitable for large-scale screening in low-data conditions. The model is calibrated using the Cathedral of Reggio Calabria and applied to the Church of San Giovanni Battista dei Fiorentini in Naples. Key outputs include simplified capacity curves and performance indicators. The methodology addresses current limitations in conventional approaches by offering an accessible tool for rapid assessment of cultural infrastructure. Future developments may incorporate AI and machine learning (AI/ML) techniques to improve typological classification and enable automated vulnerability screening at the regional scale. Full article
(This article belongs to the Special Issue Earthquake and Multi-Hazard Resilience: Community-Level Insights and AI/ML Applications)
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20 pages, 3117 KB  
Article
Effect of Waste Mask Fabric Scraps on Strength and Moisture Susceptibility of Asphalt Mixture with Nano-Carbon-Modified Filler
by Mina Al-Sadat Mirjalili and Mohammad Mehdi Khabiri
Infrastructures 2025, 10(9), 233; https://doi.org/10.3390/infrastructures10090233 - 3 Sep 2025
Viewed by 334
Abstract
This research investigates the influence of waste mask fabric scraps (WMFSs) and nano-carbon-modified filler (NCMF) on the mechanical characteristics and durability of hot mix asphalt, aiming to improve pavement performance concerning tensile stress, fatigue, and moisture damage using recycled materials. Asphalt mixtures were [...] Read more.
This research investigates the influence of waste mask fabric scraps (WMFSs) and nano-carbon-modified filler (NCMF) on the mechanical characteristics and durability of hot mix asphalt, aiming to improve pavement performance concerning tensile stress, fatigue, and moisture damage using recycled materials. Asphalt mixtures were created with aggregate and WMFS/NCMF at 0.3% and 0.5% weight percentages (relative to aggregate), with fiber lengths of 8, 12, and 18 mm, utilizing a ‘wet mixing’ method where fibers were incrementally added to aggregates during mixing. The samples underwent indirect tensile strength, moisture susceptibility, and Marshall stability testing. The results demonstrated that incorporating WMFSs and NCMF initially enhanced tensile strength, moisture susceptibility resistance, and Marshall stability, reaching an optimal point; beyond this, further fiber addition diminished these properties. Data analysis identified the sample containing 0.3% fibers at a 12 mm length as the superior performer, showcasing the highest ITS and Marshall stability values. Statistical t-tests revealed significant differences between fiber-containing samples and control groups, verifying the beneficial impact of WMFSs and NCMF. Design-Expert software (Design-Expert 12.0.3) was used to develop functional models predicting asphalt properties based on fiber percentage and length. The optimal combination—12 mm fiber length and 0.3% WMFS/NCMF—demonstrated a 33% increase in tensile strength, a 17% improvement in moisture resistance, and a 70% reduction in fatigue deformation. Safety protocols, including thermal decontamination of WMFSs, were implemented to mitigate potential health risks. Full article
(This article belongs to the Topic Sustainable Construction Materials, Processes, and Automation Technologies)
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22 pages, 1923 KB  
Article
Probability-Based Macrosimulation Method for Evaluating Airport Curbside Level of Service
by Seth Gatien, Ata M. Khan and John A. Gales
Infrastructures 2025, 10(9), 232; https://doi.org/10.3390/infrastructures10090232 - 3 Sep 2025
Viewed by 487
Abstract
The air transportation industry is challenged to address airport curbside delay problems that affect landside service quality and can potentially impact check-in operations. Methodological advances guided by industry requirements are needed to support curbside improvement studies. Existing methods require verification of assumptions prior [...] Read more.
The air transportation industry is challenged to address airport curbside delay problems that affect landside service quality and can potentially impact check-in operations. Methodological advances guided by industry requirements are needed to support curbside improvement studies. Existing methods require verification of assumptions prior to application or need expensive surveys to acquire data for use in microsimulations. A probability-based macrosimulation method is advanced for the evaluation of the level of service and capacity of the curbside processor. A key component of the method is the simulation of the stochastic balance of demand and available curb space for unloading/loading tasks using the Monte Carlo simulation model. The method meets the planning and operation requirements with the ability to analyze conditions commonly experienced at the curb area. Example applications illustrate the flexibility of the method in evaluating existing as well as planned facilities of diverse designs and sizes. The developed method can contribute to curbside processor delay reduction and due to the macroscopic nature of the method, the data requirements can be met by an airport authority without costly surveys. Full article
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28 pages, 6948 KB  
Article
Deformation Characteristics of Narrow Coal Pillar Roadway Incorporating the Roof Cutting Technique
by Changle Ma, Yuewen Pan, Feng Zhou and Yafei Zhou
Infrastructures 2025, 10(9), 231; https://doi.org/10.3390/infrastructures10090231 - 2 Sep 2025
Viewed by 356
Abstract
In order to enable safe pillarless mining in a deep, thick coal seam with a hard roof, an integrated approach combining presplitting roof blasting and a flexible formwork concrete support system was implemented and evaluated via theoretical analysis, numerical simulation, and field trials. [...] Read more.
In order to enable safe pillarless mining in a deep, thick coal seam with a hard roof, an integrated approach combining presplitting roof blasting and a flexible formwork concrete support system was implemented and evaluated via theoretical analysis, numerical simulation, and field trials. The limit-equilibrium analysis indicated a minimum gob-side coal pillar width of approximately 6 m. A pumpable C40 flexible-formwork concrete was developed, achieving its design compressive strength within 28 days, to serve as a roadside support. Field implementation of the presplitting and composite support effectively controlled roadway deformation: total roof–floor convergence was limited to 340 mm (floor heave accounted for 65%), and support loads remained within safe ranges, with no structural failures observed. These results demonstrate that the proposed gob-side entry retaining technique maintains roadway stability without a coal pillar, offering a practical and economic solution for deep coal mines with hard roofs. Full article
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16 pages, 2689 KB  
Article
A Calibration Approach for Short-Circuit Fault in Electrified Railway Bidirectional Power Supply System
by Yan Xia, Ke Huang, Yunchuan Deng, Zhigang Liu and Jingkun Liang
Infrastructures 2025, 10(9), 230; https://doi.org/10.3390/infrastructures10090230 - 1 Sep 2025
Viewed by 384
Abstract
Compared to the traditional unidirectional power supply system, the bidirectional traction power supply system in an electrified railway offers advantages like improved traction voltage and reduced energy losses, making it more suitable for steep gradient routes. However, its increased electrical complexity necessitates advanced [...] Read more.
Compared to the traditional unidirectional power supply system, the bidirectional traction power supply system in an electrified railway offers advantages like improved traction voltage and reduced energy losses, making it more suitable for steep gradient routes. However, its increased electrical complexity necessitates advanced catenary-rail short-circuit fault calculations and relay protection calibration. This paper proposes a fault calibration approach based on deriving electrical quantities with fault distance in the railway bidirectional traction grid system. A multi-loop circuit modeling method is used to accurately model the traction grid system and impedance parameters, incorporating real loop circuits formed by the grid transmission and return conductors for the first time. The approach is validated through real-life experiments on a Chinese railway line. A case study of a direct power supply system with a return cable is used to derive electrical quantities. Faults are categorized into two sections: between the substation and the parallel station (PS), and between the PS and the section post (SP). For each section, electrical quantities are derived under unidirectional substation excitation, and the results are superimposed to obtain fault distance variation curves for currents and voltages of substation, PS, SP, and Thévenin impedance. Finally, a calibration strategy for relay protection is presented. Full article
(This article belongs to the Special Issue The Resilience of Railway Networks: Enhancing Safety and Robustness)
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11 pages, 1915 KB  
Article
Thermal Effect on Fiber-Reinforced Concrete Link Slab with Existing Bearing Modification
by Kuang-Yuan Hou, Yifan Zhu, Naiyi Li and Chung C. Fu
Infrastructures 2025, 10(9), 229; https://doi.org/10.3390/infrastructures10090229 - 31 Aug 2025
Viewed by 452
Abstract
This paper analyzes the long-term thermal effect of newly applied fiber-reinforced concrete link slabs on an existing steel bridge for a rehabilitation project of the Maryland Transportation Authority. To enhance structural resilience, thermal movement is one of the major concerns in concrete link [...] Read more.
This paper analyzes the long-term thermal effect of newly applied fiber-reinforced concrete link slabs on an existing steel bridge for a rehabilitation project of the Maryland Transportation Authority. To enhance structural resilience, thermal movement is one of the major concerns in concrete link slab design. To accommodate the global thermal expansion of a full bridge, the existing fixed bearings were modified to expansion bearings to release the longitudinal thermal movement of the super-structure. Their movements were measured by the installed LVDT devices. In this pilot study for the Maryland Transportation Authority (MDTA), engineered cementitious composite (ECC) and ultra-high-performance concrete (UHPC) were selected as candidate materials for link slabs to replace traditional steel expansion joints. To evaluate the performances of ECC and UHPC, built-in strain gauges were implemented for long-term field monitoring to ensure the durability of link slabs. For comparison, the measured data were collected over two full years to study their thermal effects in order to evaluate their sustainability. The novelty of the study is in comparing the performance of different materials side-by-side using true sensor measurements and numerical simulation. Thermal movement performance, including thermal cracking, will be one of the major selection criteria for the link slab material. Full article
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27 pages, 1057 KB  
Review
Distributed Acoustic Sensing for Road Traffic Monitoring: Principles, Signal Processing, and Emerging Applications
by Jingxiang Deng, Long Jin, Hongzhi Wang, Zihao Zhang, Yanjiang Liu, Fei Meng, Jikai Wang, Zhenghao Li and Jianqing Wu
Infrastructures 2025, 10(9), 228; https://doi.org/10.3390/infrastructures10090228 - 29 Aug 2025
Viewed by 900
Abstract
With accelerating urbanization and the exponential growth in vehicle populations, high-precision traffic monitoring has become indispensable for intelligent transportation systems (ITSs). Conventional sensing technologies—including inductive loops, cameras, and radar—suffer from inherent limitations: restrictive spatial coverage, prohibitive installation costs, and vulnerability to adverse weather. [...] Read more.
With accelerating urbanization and the exponential growth in vehicle populations, high-precision traffic monitoring has become indispensable for intelligent transportation systems (ITSs). Conventional sensing technologies—including inductive loops, cameras, and radar—suffer from inherent limitations: restrictive spatial coverage, prohibitive installation costs, and vulnerability to adverse weather. Distributed Acoustic Sensing (DAS), leveraging Rayleigh backscattering to convert standard optical fibers into kilometer-scale, real-time vibration sensor networks, presents a transformative alternative. This paper provides a comprehensive review of the principles and system architecture of DAS for roadway traffic monitoring, with a focus on signal processing techniques, feature extraction methods, and recent advances in vehicle detection, classification, and speed/flow estimation. Special attention is given to the integration of deep learning approaches, which enhance noise suppression and feature recognition under complex, multi-lane traffic conditions. Real-world deployment cases on highways, urban roads, and bridges are analyzed to demonstrate DAS’s practical value. Finally, this paper delineates emerging research trends and technical hurdles, providing actionable insights for the scalable implementation of DAS-enhanced ITS infrastructures. Full article
(This article belongs to the Special Issue Sustainable Road Design and Traffic Management)
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27 pages, 3818 KB  
Article
A Novel Master Curve Formulation with Explicitly Incorporated Temperature Dependence for Asphalt Mixtures: A Model Proposal with a Case Study
by Gilberto Martinez-Arguelles, Diego Casas, Rita Peñabaena-Niebles, Oswaldo Guerrero-Bustamante and Rodrigo Polo-Mendoza
Infrastructures 2025, 10(9), 227; https://doi.org/10.3390/infrastructures10090227 - 28 Aug 2025
Viewed by 444
Abstract
Accurately modelling and simulating the stiffness modulus of asphalt mixtures is essential for reliable pavement design and performance prediction under varying environmental and loading conditions. The preceding is commonly achieved through master curves, which relate stiffness to loading frequency at a reference temperature. [...] Read more.
Accurately modelling and simulating the stiffness modulus of asphalt mixtures is essential for reliable pavement design and performance prediction under varying environmental and loading conditions. The preceding is commonly achieved through master curves, which relate stiffness to loading frequency at a reference temperature. However, conventional master curves face two primary limitations. Firstly, temperature is not treated as a state variable; instead, its effect is indirectly considered through shift factors, which can introduce inaccuracies due to their lack of thermodynamic consistency across the entire range of possible temperatures. Secondly, conventional master curves often encounter convergence difficulties when calibrated with experimental data constrained to a narrow frequency spectrum. In order to address these shortcomings, this investigation proposes a novel formulation known as the Thermo-Stiffness Integration (TSI) model, which explicitly incorporates both temperature and frequency as state variables to predict the stiffness modulus directly, without relying on supplementary expressions such as shift factors. The TSI model is built on thermodynamics-based principles (such as Eyring’s rate theory and activation free energy) and leverages the time–temperature superposition principle to create a physically consistent representation of the mechanical behaviour of asphalt mixtures. This manuscript presents the development of the TSI model along with its application in a case study involving eight asphalt mixtures, including four hot-mix asphalts and four warm-mix asphalts. Each type of mixture contains recycled concrete aggregates at replacement levels of 0%, 15%, 30%, and 45% as partial substitutes for coarse natural aggregates. This diverse set of materials enables a robust evaluation of the model’s performance, even under non-traditional mixture designs. For this case study, the TSI model enhances computational stability by approximately 4 to 45 times compared to conventional master curves. Thus, the main contribution of this research lies in establishing a valuable mathematical tool for both scientists and practitioners aiming to improve the design and performance assessment of asphalt mixtures in a more physically realistic and computationally stable approach. Full article
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22 pages, 8341 KB  
Article
Performance Evaluation of a Sustainable Glulam Timber Rubrail and Noise Wall System Under MASH TL-3 Crash Conditions
by Tewodros Y. Yosef, Ronald K. Faller, Qusai A. Alomari, Jennifer D. Schmidt and Mojtaba Atash Bahar
Infrastructures 2025, 10(9), 226; https://doi.org/10.3390/infrastructures10090226 - 26 Aug 2025
Viewed by 542
Abstract
Noise barriers are commonly used to reduce the adverse effects of traffic noise in both urban and suburban settings. While conventional systems constructed from concrete and steel provide reliable acoustic and structural performance, they raise sustainability concerns due to high embodied energy and [...] Read more.
Noise barriers are commonly used to reduce the adverse effects of traffic noise in both urban and suburban settings. While conventional systems constructed from concrete and steel provide reliable acoustic and structural performance, they raise sustainability concerns due to high embodied energy and carbon emissions. Glued-laminated (glulam) timber has emerged as a sustainable alternative, offering a reduced carbon footprint, aesthetic appeal, and effective acoustic performance. However, the crashworthiness of timber-based noise wall systems remains under investigated, particularly with respect to the safety criteria established in the 2016 edition of the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH). This study presents the full-scale crash testing and evaluation of glulam rubrail and noise wall systems under MASH Test Level 3 (TL-3) impact conditions. Building on a previously tested system compliant with National Cooperative Highway Research Program (NCHRP) Report 350, modifications were made to increase rubrail dimensions to meet higher lateral design loads. Three full-scale vehicle crash tests were conducted using 1100C and 2270P vehicles at 100 km/h and 25 degrees, covering both front- and back-mounted wall configurations. All tested systems demonstrated acceptable structural performance, effective vehicle redirection, and compliance with MASH 2016 occupant risk criteria. There was no penetration or potential for debris intrusion into the occupant compartment, and all measured occupant risk values remained well below allowable thresholds. Minimal damage to structural components was observed. The results confirm that the modified glulam noise wall system meets current impact safety standards and is suitable for use along high-speed roadways. This work supports the integration of sustainable materials into roadside safety infrastructure without compromising crash performance. Full article
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23 pages, 3619 KB  
Article
Towards Smarter Infrastructure Investment: A Comprehensive Data-Driven Decision Support Model for Asset Lifecycle Optimisation Using Stochastic Dynamic Programming
by Neda Gorjian Jolfaei, Leon van der Linden, Christopher W. K. Chow, Nima Gorjian, Bo Jin and Indra Gunawan
Infrastructures 2025, 10(9), 225; https://doi.org/10.3390/infrastructures10090225 - 23 Aug 2025
Viewed by 429
Abstract
Equipment renewal and replacement strategy as well as smart capital investment is a vital focus in engineering asset management, particularly for water utilities aiming to improve asset reliability, water quality, service continuity and affordability. This study presents a novel decision support model that [...] Read more.
Equipment renewal and replacement strategy as well as smart capital investment is a vital focus in engineering asset management, particularly for water utilities aiming to improve asset reliability, water quality, service continuity and affordability. This study presents a novel decision support model that integrates whole-life costing principles across all asset lifecycle phases—from capital delivery and daily operations to long-term maintenance. The proposed model uniquely combines asset degradation and failure patterns, operating and maintenance costs, and the impact of technological advancements to provide a holistic and comprehensive asset management decision-making tool. These dimensions are jointly analysed using a hybrid approach that combines optimisation with stochastic dynamic programming, allowing for the determination of optimal asset renewal and replacement timing. The model’s performance was validated using historical data from eight critical wastewater pump stations within a township’s sewerage network. This was performed by comparing the model’s cost-saving results to those achieved by the water utility’s current strategy. Results revealed that the proposed model achieved an average cost saving of 12%, demonstrating its effectiveness in supporting sustainable and cost-efficient asset renewal decisions. Full article
(This article belongs to the Section Smart Infrastructures)
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17 pages, 5462 KB  
Article
Degradation and Sustainability: Analysis of Structural Issues in the Eduardo Caldeira Bridge, Machico
by Raul Alves, Sérgio Lousada, José Manuel Naranjo Gómez and José Cabezas
Infrastructures 2025, 10(9), 224; https://doi.org/10.3390/infrastructures10090224 - 22 Aug 2025
Viewed by 815
Abstract
This paper presents a detailed analysis of the severe structural anomalies that led to the urgent rehabilitation of the Eduardo Caldeira Bridge in Machico, Madeira. Situated in a challenging coastal environment with complex volcanic geology, the bridge exhibited a critical failure of its [...] Read more.
This paper presents a detailed analysis of the severe structural anomalies that led to the urgent rehabilitation of the Eduardo Caldeira Bridge in Machico, Madeira. Situated in a challenging coastal environment with complex volcanic geology, the bridge exhibited a critical failure of its bearing devices, which were assigned the highest defect severity rating (Grade 5). A multidisciplinary diagnostic methodology, combining visual inspection data, non-destructive testing, and geotechnical analysis, was employed to identify the root causes of this degradation. The investigation concluded that the bearing failure was not due to widespread material deterioration but was directly linked to significant lateral structural displacements, exacerbated by localized geotechnical instabilities. This paper details the data-driven rehabilitation strategy that was subsequently implemented, including the complete replacement of the bearings and substructure stabilization measures. The study provides a valuable case study of a complex, mechanics-driven failure mode and demonstrates that for such critical infrastructure, a proactive management model integrating advanced technologies like Structural Health Monitoring (SHM) and Building Information Modelling (BIM) is essential for ensuring long-term safety and resilience. Full article
(This article belongs to the Special Issue Sustainable Bridge Engineering)
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