The increasing environmental concerns associated with traditional construction materials have forced the exploration of sustainable alternatives, such as biomaterials in cement-based composites. Despite their potential to significantly reduce carbon footprints and enhance environmental sustainability, comprehensive literature analyzing the integration, characteristics, and behavior of biomaterials within cement matrices remains sparse. This gap underscores a crucial need for a review to consolidate existing knowledge and identify future research trajectories. This study aims to conduct a review of the characteristics and behavior of cement-based composites with biomaterials. It also aims to establish a clear understanding of how biomaterials affect the physical, mechanical, and durability properties of cement-based composites. To maintain a clearly defined objective, this review is guided by three questions: (i) which biomaterial families have been investigated in cement-based composites and how they are integrated at binder, aggregate, fiber, and biologically mediated levels; (ii) what mechanisms most consistently explain reported changes in fresh properties, mechanical performance, and transport-related behavior; and (iii) which testing and monitoring approaches are used to quantify long-term performance, durability, and serviceability implications. The focus extends to evaluating the environmental impact through lifecycle analyses and the potential reduction in carbon emissions. The importance of this research lies in its ability to provide a robust foundation for future innovations in construction material technology. By highlighting current trends and gaps, it serves as a critical resource for researchers and industry practitioners aiming to develop more sustainable building solutions. Moreover, this review is poised to inform policy-making by presenting empirically supported data on the benefits and challenges associated with biomaterials in construction, thereby promoting more informed decisions towards sustainable urban development.
This study presents a comparison study between a Tuned Mass Damper (TMD) and Multiple Tuned Mass Dampers (MTMD). The main novelty of this study lies in the unified optimization-based comparison of optimized and fixed-mass MTMD configurations, highlighting the trade-off between seismic performance and practical applicability compared to a single large TMD installed at the top of the building. The Jaya algorithm is used to determine the optimum solution of mass damper parameters. Three cases are examined. The first case is the building with the TMD system. The second case is the building with the MTMD system. Tuned mass dampers are connected to each floor; the masses of these dampers are optimized using the Jaya algorithm. In the third case, the building is fitted with an MTMD system whose damper mass is fixed at 50,000 kg rather than optimized. Comparisons are made between the cases in terms of vibration energy distribution and floor displacement reduction ratio. The results show that all systems are effective in reducing energy vibration and floor displacements. The optimized MTMD system provides superior performance compared to the TMD system, while the fixed-mass MTMD system exhibits lower control efficiency but offers a more practical alternative to a single large TMD installed at the top of the building.
Sinking wells (open caissons) are widely used deep foundation structures whose installation by the cut-and-sink method may lead to unintended deviation from verticality due to heterogeneous soil conditions and construction irregularities. While tilting is a frequently observed phenomenon, quantitative criteria for assessing the admissibility of an inclined well after completion of sinking remain insufficiently defined. This study presents a static analytical framework for evaluating stress redistribution beneath the concrete plug of a tilted well. The analysis is based on eccentric vertical load transfer and derives closed-form relationships linking the permissible inclination angle to well geometry (radius r, height H) and the ratio of total weight to shaft weight (Gc/G). A practical admissibility criterion is proposed by limiting the increase in maximum contact stress to 20% relative to the vertical configuration (σ1 ≤ 1.2σ). Parametric calculations performed for typical well dimensions (r = 2–5 m, H = 4–9 m) indicate that admissible inclination angles vary approximately from 1.6° to 11.6°, depending on geometric proportions and load distribution. The results demonstrate that stress amplification is governed primarily by bending moment induced by eccentricity rather than by axial load increase. The proposed formulation provides a transparent engineering tool enabling rapid assessment of whether a tilted sinking well may remain in service without exceeding acceptable soil stress amplification.
The outstanding performance of unplasticized polyvinyl chloride (UPVC) has led to its widespread use in urban underground pipeline systems. However, understanding the effects of high-temperature industrial wastewater on the buried pipes is very complicated. To investigate the influence of industrial wastewater on the safety of pipes, the mechanical properties were tested using the material specimens. The changes in mechanical properties caused by the environmental temperature and heat cycles were experimentally analyzed. Empirical formulas to predict the mechanical parameters of UPVC pipe material were proposed. The ultimate strength of underground urban pipes was numerically studied by the parametric analysis. Results show that the maximum stress and ductility of UPVC pipe material decrease significantly as the ambient temperature and heat cycle increase. The ultimate strength of the underground pipe decreases exponentially with the increase in the ambient temperature. Both the temperature amplitude and the number of heat cycles have significant influences on the performance of the underground pipes.
The paper presents an analysis of measured geometric imperfections in cold-formed aluminium alloy channel members that is the base for the proposal of representative values for each imperfection component for use in future research and design standards. Cold-formed aluminium alloy sections have recently been developed and found to be more cost-effective than conventional extruded sections. Cold-formed metal sections typically contain significant geometric imperfections; the effects of these imperfections have been demonstrated in numerous previous studies and should therefore be considered in analyses. Cold-formed aluminium sections remain relatively new worldwide, and available data on their geometric imperfections are still limited. This study, therefore, compiles measured imperfection data from a national research project on cold-formed aluminium sections. These data are classified according to individual imperfection components, and then representative values are proposed based on section thickness and slenderness. The proposed values are validated through comparison between finite element model predictions and experimental results for cold-formed aluminium alloy channel members. It is found that very good agreement is observed between the two results. The paper also provides coefficients of variation to account for the effects of geometric imperfections on the strength of cold-formed aluminium members. These coefficients can be considered for inclusion in design standards.
Low-frequency ultrasonic array is commonly used to detect interlayer voids located in high-speed railway ballastless track, which is a typical multilayer concrete bonded structure. The difficulty of detection lies in the fact that the total focusing method (TFM) based on a single fixed sound velocity model cannot adapt to the acoustic propagation characteristics of multilayer structures, which is prone to generating artifacts. In addition, the long duration of low-frequency ultrasonic pulses is prone to causing significant deviations in defect localization. To address these issues, a theoretical model of the layered bonded structure is proposed. The acoustic wave propagation path and travel time calculation are clarified after combining the Fermat’s principle and Snell’s law, and the shortest path ray tracing (SPRT) is proposed, which achieves visual imaging of interlayer voids; The pulse peak delay (PPD) is applied to correct the travel time of low-frequency ultrasonic waves, and the shortest path ray tracing combined with pulse peak delay (PSPRT) is proposed, which significantly improves the localization accuracy of defects. Finally, by integrating the amplitude and phase information of scattered signals, the shortest path ray tracing based on pulse peak delay and sign coherence factor (PPSPRT) is constructed, which significantly enhances the SNR. The test results show that, compared with the conventional TFM, the proposed PPSPRT achieves average SNR improvements of 6.62 dB in numerical simulations and 14.30 dB in field tests, and reduces the average depth localization error of interlayer voids to merely 23.49% and 10.38% of that of TFM under corresponding test conditions, respectively. PPSPRT can provide important guidance for accurate imaging of interlayer voids.
Basalt fiber (BF), derived from abundant volcanic rock in China, represents a sustainable reinforcement material for pavement engineering, addressing challenges like durability, corrosion, and environmental impact. This comprehensive review synthesizes BF’s properties, including high tensile strength (3000–4800 MPa), thermal stability (−269°C to 700°C), and superior chemical resistance compared to steel or polypropylene fibers. Production involves melting basalt at 1450°C–1500°C, with China leading in resources and standards like JT/T776.1-2010. Applications in asphalt concrete enhance rutting resistance by 30%–50% and fatigue life by 20%–40%, while in cement concrete, BF improves crack resistance and impermeability by 30%–55%. BF composite rebars offer corrosion-free alternatives for bridges and pavements, reducing energy consumption to 46% of steel equivalents. Engineering practices, including mix designs and construction methods, demonstrate economic viability and sustainability benefits, aligning with China’s “Made in China 2025” initiatives. Future prospects emphasize hybrid systems and standardization for broader adoption.
To bridge the gap between isolated structural and connection analyses in lightweight rail vehicle design, this study establishes an integrated modelling-simulation-verification framework. This integrated framework, developed via parametric FE modelling, multi-axial load simulation (per DIN EN 12663 & BS 7608), and standards-based verification, was applied to a specific housing design. Key results: (1) Under vertical ±3 g static loads, the tray experiences the maximum equivalent stress of 186.6 MPa, yielding a safety factor of 1.1 against the yield strength, which satisfies the minimum requirement (s1 ≥ 1.15) of the DIN EN 12663 standard. (2) Under fatigue spectrum, critical stress amplitudes are 39.38 MPa (lifting seat) and 37.87 MPa (frame), yielding fatigue safety factors of 2.54 and 2.64 (BS 7608 Class B). For the reliability assessment of similar rail transit equipment. The demonstrated framework effectively bridges the gap between isolated structural and connection analyses, providing a systematic tool for lightweight, reliable design. The framework provides validated design data and a reusable methodology for lightweight rail equipment.
This study systematically investigates the static and dynamic performance of the comprehensive structural system for the Huangmaohai extra-long-span three-tower cable-stayed bridge. A full-bridge finite element model was developed, incorporating elastic restraints at the central tower, viscous dampers at the side towers, and transverse seismic isolation bearings. Detailed structural parameters and loading conditions are provided. Subsequently, a systematic analysis was conducted on the structural stiffness, internal forces in the bearings, and stresses in the main girder and stay cables under static loads, thereby verifying the structural safety during both the completed bridge state and operational phase. Finally, through dynamic characteristic and seismic response analyses, the internal forces and displacement responses of the bridge towers in the baseline model and the comprehensive model under E1 and E2 seismic actions were compared. The results indicate that the proposed comprehensive structural system effectively controls main girder stresses, enhances structural stiffness, and significantly reduces seismic-induced internal forces. This research provides crucial technical bearing for the design and seismic optimization of similar extra-long-span cable-stayed bridges.
The vibration and resonance behavior of steel frame structures are significantly affected by connection flexibility and geometric nonlinearity. Conventional vibration analyses often assume fully rigid beam-column connections and neglect second-order effects, which can lead to inaccurate predictions of natural frequencies and resonance conditions. This study proposes a finite element-based approach for the vibration analysis of planar steel frames with linear and nonlinear semi-rigid connections, explicitly incorporating geometric nonlinearity. Beam-column connections are modeled using nonlinear moment-rotation relationships, while elastic and geometric stiffness matrices, together with a consistent mass matrix, are integrated into the governing dynamic equations. The time-history response is computed using the Newmark integration scheme. The proposed formulation is validated through benchmark examples and comparisons with published results and commercial finite element software. Numerical results reveal that the combined effects of semi-rigid connections and geometric nonlinearity significantly alter the effective structural stiffness, leading to noticeable variations in natural vibration frequencies. In particular, the fundamental frequency evolves during dynamic response, resulting in resonance shifting and time-dependent resonance behavior. These findings suggest that resonance in steel frames with semi-rigid connections should be regarded as a state-dependent phenomenon rather than a fixed structural property, with important implications for vibration assessment and resonance control in structural design.
Ultra-high performance concrete (UHPC) exhibits exceptional mechanical properties and durability, making it highly suitable for infrastructure applications. This paper presents the design and evaluation of an innovative steel frame-UHPC composite deck intended for temporary trestles subjected to heavy construction loads and corrosive environments. The mechanical performance of the proposed composite deck was investigated through advanced finite element modeling and full-scale experimental testing. Structural responses of the trestle structure equipped with the composite deck under a 150-t crawler crane were analyzed numerically, while a three-point bending test on a full-scale steel frame-UHPC composite deck determined its flexural capacity and failure mechanisms. Stress distribution and deformation under bending loads were examined using calibrated numerical models and experimental data. Moreover, a parametric study was performed to assess the influence of key design variables. Results indicate that the steel frame-UHPC composite deck achieved an ultimate mid-span bending moment of 271.6 kN·m. Crack propagation in the UHPC panel of the composite deck was characterized by multiple, progressive cracks, demonstrating favorable ductility and early-warning capacity of the deck system. These findings confirm that the steel frame-UHPC composite deck offers high load-bearing capacity, flexural ductility, and favorable durability, supporting its use in heavy-duty trestle bridges and corrosive environments.
Ultra-high-performance concrete (UHPC) exhibits high strength, toughness, and durability, making it an excellent candidate for integration with novel high-ductility, high-strength negative Poisson’s ratio (NPR) steel bars. This combination shows promising applications in the fields of bridges and buildings. This study investigates the bonding performance of various types of NPR bars (smooth NPR bars, spiral rib NPR bars, and NPR steel strands) with UHPC as the concrete matrix. It examines the effects of bond length, bar diameter, and NPR bar type on bonding performance, comparing these results with those of normal concrete (NC). A predictive model for the bonding performance of NPR bars with UHPC was developed. Results show that in the UHPC matrix, all types of NPR bars primarily exhibit pullout failure, with bond strength exceeding that of the NC matrix group by 47.07%. The use of NPR bars improves ductility, with all groups demonstrating better ultimate slip compared to traditional steel bars. An increase in bond length reduces the ultimate strength of all NPR bar types while simultaneously increasing ultimate slip. Similarly, a larger bar diameter decreases the ultimate strength of NPR steel strands by 32.32% and increases slip. During this process, the expansion effect of the strand wires complicates the loading conditions during pullout. Among the three NPR bar types, spiral rib NPR bars exhibit the highest ultimate strength but relatively low slip. In contrast, smooth NPR bars and NPR steel strands have lower ultimate strength but allow for greater slip. The parameter, empirical, and composite models developed in this study demonstrate strong predictive accuracy, with most models achieving an R2 value above 0.7. These models reliably estimate the ultimate strength and slip of NPR bars in UHPC. These findings provide a solid theoretical foundation and practical guidance for the application of NPR bars in UHPC.
Ground-penetrating radar (GPR) imaging is widely used for detecting hidden defects in urban roads. However, the complex noise environment, large-scale variations in defect features, and the sensitivity of slender defects to annotation errors pose significant challenges to accurate detection. To address these issues, this study proposes an improved object detection framework, termed DFF-MoCA-YOLO, based on YOLOv11 for identifying void and loose defects in GPR images. First, a multi-strategy gated feature fusion module (MSGFF-C3k2) is designed to enhance feature robustness against complex noise and scale variations. Then, a Monte Carlo Attention (MoCAttention) module is introduced to improve defect-feature representation via stochastic sampling and channel recalibration. Subsequently, an adaptive aspect-ratio penalty CIoU loss (CIoU-ARP) is developed to improve bounding box regression accuracy for slender defects. A labeled dataset containing void and loose defects is constructed using multi-source GPR data collected from eight urban roads. Finally, a series of ablation experiments is conducted on the proposed modules. Experimental results demonstrate that the proposed method achieves consistent performance improvements over the baseline YOLOv11 and other mainstream YOLO variants, while maintaining relatively low computational complexity. The results indicate that the proposed framework offers an effective and practical solution for detecting hidden defects in urban roads using GPR images. Moreover, the model’s robustness to noise and ability to accurately detect defects at varying scales make it a promising tool for urban infrastructure maintenance. Its efficient performance with minimal computational overhead makes it suitable for real-time defect detection.
Buried natural gas pipelines are critical components of energy infrastructure, and their durability and safe operation depend on effective structural health monitoring and the early identification of damage states. In farmland environments, rotary tillage imposes repeated and often concealed mechanical loads on buried pipelines, resulting in stress accumulation, progressive deterioration, and potentially structural failure. However, predictive and interpretable health monitoring approaches that explicitly incorporate rotary tiller-induced damage mechanisms remain scarce. In this study, a physics-informed and interpretable hybrid framework is proposed for the structural health monitoring of buried pipelines subjected to rotary tiller loading. A three-dimensional multiphysics-coupled finite element model of the rotary tiller-pipeline-soil system was developed to simulate the mechanical response and damage evolution of pipelines under varying wall thickness, internal pressure, blade number, operating speed, and soil density. Based on the simulation results, pipeline conditions were classified into three damage states, namely elastic deformation, plastic deformation, and failure, with the first two regarded as warning states. A multi-class CatBoost model optimized using Particle Swarm Optimization (PSO) was subsequently established for damage-state identification. On the test set, the model achieved an accuracy of 0.94, and the AUC values for all three classes reached 0.93. SHapley Additive exPlanations (SHAP) were further employed to interpret the model outputs and quantify the contribution of individual parameters. The results revealed critical risk thresholds associated with the transition from warning states to failure under the shallow-cover rotary tiller disturbance scenario considered in this study. In particular, the risk of failure increased markedly when the blade number exceeded eight and the internal pressure was greater than 8 MPa. These findings indicate that wall thickness and internal pressure govern the baseline structural resistance of pressurized pipelines, while the identified thresholds can support the screening of high-risk conditions and the operational control of shallow-cover farmland sections.
