Abstract This study investigates the effect of socket joint construction on the crash performance of prefabricated rectangular reinforced concrete (RC) bridge piers subjected to vehicle collision. Key parameters, including pier column embedment depth, socket gap, and interface roughness, were examined. Six scaled model piers (five socket‐connected and one cast‐in‐place) with identical dimensions and materials were subjected to simulated vehicle impact tests. The collision force, acceleration response, strain evolution, and failure modes were recorded. The results show that vehicle speed is a dominant factor governing the dynamic response of socket bridge piers. The maximum collision force is significantly influenced by the column embedment depth, although no consistent quantitative relationship was identified. Interface roughness has a greater effect at higher vehicle speeds. Damage severity increases with vehicle speed, typically presenting as localized crushing at the impact area and structural damage near the pier base. Shallow embedment depths and narrow socket gaps contribute to more severe damage patterns. Acceleration response rises with vehicle speed but shows no clear correlation with embedment depth. Residual reinforcement strain is more pronounced in piers with shallow embedment or narrow socket gaps. These findings offer critical reference data for understanding the collision response of socket bridge piers and support the design of crash‐resistant prefabricated bridge structures.

Abstract Prestressed concrete provides several advantages over traditional reinforced concrete; however, some markets remain skeptical about the use of post‐tensioned structures. A crucial factor in these structures is assessing and quantifying the final force introduced into the element. This study evaluates the application of distributed optical fiber sensors (DOFS) to monitor the response of beams during tendon force introduction, long‐term behavior, and loading to failure. An experimental campaign was conducted involving four beams: two standard and two post‐tensioned. Additionally, the study compares the effectiveness of steel fiber reinforced concrete to determine its potential for further optimizing beam design. Key aspects analyzed include tendon force and corresponding instantaneous and deferred losses, load‐deformation behavior, initial crack formation, and subsequent crack development. The results demonstrated that using DOFS in a straightforward manner allows for detailed beam response analysis across different phases. Simple hypotheses and limited sensors can accurately evaluate all tendon losses. Furthermore, fiber optics can detect potential crack candidates even in the compression stage, due to strain concentrations that lead to cracking during the loading phase.

Abstract The limb‐length ratio ( ψ ) significantly affects the mechanical properties of L‐shaped concrete‐filled steel tube (L‐CFST) columns. This study investigates the influence of the ψ and stiffeners on the uniaxial compressive properties of L‐CFST columns through the design and testing of 11 inequiaxial and stiffened L‐shaped concrete‐filled steel tube (IS‐L‐CFST) columns. The results reveal that the specimens show no noticeable deformation before the peak load. The final failure mode is characterized by buckling in the middle and bottom portions of the steel tube. As the ψ increases, both the compressive capacity and stiffness of the specimens improve, while ductility and energy dissipation decrease. Stiffening rib (SR) also enhances specimen stiffness, the steel tube's confinement effect on the core concrete, and improves ductility and energy dissipation. The bearing capacity of the specimens increases by 11.3% and 11.9% for ψ values of 1.4 and 1.6, respectively. Finite element models (FEMs) of IS‐L‐CFST columns were developed, showing that the peak stress in the long side concrete decreases as ψ increases. However, the constraint effect of the steel tube on the long side concrete improves with the addition of SR. The ψ does not significantly affect the stress of the steel tube, though stress in the steel tube decreases during the descending phase when SR is used. The error between simulated and experimental bearing capacities is less than 5%. The AISC standard based on the superposed strength theory can be used to calculate the bearing capacity of IS‐L‐CFST columns.

Abstract This paper provides an overview and background for the expressions given in the draft Australian Concrete Structures Standard (AS3600‐202X) with respect to flexural crack widths in fiber‐reinforced concrete (FRC) elements containing conventional reinforcement. The proposed model has been adapted from the existing expression for plain reinforced concrete and accounts for the beneficial effects of the fibers (steel and polypropylene) in the short‐ and long‐term and accounts for behavior observed in large‐scale long‐term test data. The benefit of this approach is that a single (unified) expression may be used to determine the short‐ and long‐term cracking behavior of conventionally reinforced or FRC elements subjected to flexure.

Abstract The construction industry, as one of the three major high‐energy‐consuming sectors, faces increasing pressure to embrace sustainable practices. As part of this transition, green prefabricated buildings have emerged as a key solution, with prefabricated steel truss composite floors becoming essential due to their environmentally friendly construction process and reduced building timelines. However, the cracking of steel truss composite slabs during transportation and storage remains a critical challenge. This study primarily aims to address this issue by introducing steel fibers derived from waste tires, replacing conventional steel fibers, to enhance the structural integrity of these slabs. The research investigates the impact of industry recycled steel fibers, varying both their volume incorporation rate and length‐to‐diameter ratio, on the mechanical performance of prefabricated steel truss composite slabs. Through a series of mechanical experiments, the study analyzes crack propagation, deflection behavior, failure modes, and load‐bearing capacity. The results indicate that an increase in the recycled steel fiber volume ratio significantly improves the slab's mechanical performance, with the effect on bearing capacity being more pronounced than when altering the fiber length‐to‐diameter ratio. The experimental findings are in close agreement with numerical simulations conducted using ABAQUS software. Overall, this research highlights the potential of utilizing recycled materials in construction to improve both structural performance and sustainability, offering practical solutions that could lead to substantial cost reductions in construction projects.

Abstract Prefabricated construction technology has been widely used in the construction of subway stations due to the advantages of excellent material quality, short construction periods, and low environmental pollution, but the joint is the weakest area of prefabricated structures under environmental load. To further enhance the joint mechanical properties, a 3D finite element model of prefabricated subway stations containing prestressed steel strand joints is established; the cooling method and concrete plastic damage constitutive model are adopted to simulate the prestress effect and concrete cracking. Based on numerical simulation, the bending stiffness and shear stiffness of prestressed steel strand joints are compared to bolted joints, and the deformation and damage mechanics of prefabricated subway stations containing different types of joints under surface overloads are studied. The results show that replacing bolted joints with prestressed steel strand joints can significantly improve the joint bending stiffness and shear stiffness. When the prestress of steel strands increases to 120 kN, the maximum vertical displacement reduction rate of the joint will reach 52%. For the prefabricated subway station structures, replacing bolted joints with prestressed steel strand joints will not affect the joint deformation development trend but will change the distribution law of internal forces. When the prestress of steel strands is 80 kN, the maximum vertical and horizontal deformation reduction rates will reach 36% and 38%; the larger the surface overload, the more significant the decrease.

Abstract Fiber‐reinforced polymer (FRP) bars are increasingly used in construction due to their high strength‐to‐weight ratio and resistance to corrosion. Despite these advantages, existing design codes for FRP‐reinforced concrete columns (FRP‐RCC) lack comprehensive equations that adequately account for factors such as slenderness, eccentricity, and the contribution of FRP bars to axial capacity. This study addresses these gaps by proposing an artificial neural network (ANN) model to accurately predict the axial capacity of short, slender, concentric, and eccentric FRP‐RCCs. A comprehensive database of 490 column samples from the literature was utilized to analyze the factors influencing FRP‐RCC behavior, develop the ANN model, and validate its performance. The database also enabled a detailed evaluation of current design codes, existing ANN models, and other design equations, comparing their predictive capabilities to the proposed ANN. The results demonstrate the effectiveness of the proposed ANN model, achieving an R 2 value of 0.93 during training and testing and 0.97 during verification with an independent dataset. These findings underscore the model's robustness and practical applicability in engineering design. Furthermore, comparative analysis revealed that the proposed ANN consistently outperforms existing design equations and available ANN models, highlighting its superior predictive accuracy and potential as a reliable tool for designing FRP‐reinforced concrete structures.

Abstract Corrosion of reinforcement steel in concrete structures is a major challenge, particularly in harsh environments such as coastal and industrial areas, where durability is critical. Conventional epoxy resin coatings offer chemical stability but face challenges in maintaining long‐term corrosion resistance under severe conditions. This study explores the application of reduced graphene oxide (rGO)‐modified epoxy resin coatings for enhancing the durability and corrosion resistance of reinforced concrete beams. By varying the rGO content, we evaluated the adhesion, water absorption, and corrosion resistance of rGO/EC (reduced graphene oxide/epoxy resin coatings). Our findings indicate that an optimal concentration of 0.2 wt.% rGO significantly improves the corrosion resistance and impermeability of the epoxy coating, while maintaining strong adhesion. Microstructural analysis and coating performance tests confirmed these improvements, and a predictive model was developed to determine the optimal rGO concentration, showing strong agreement with experimental results. The flexural tests on rGO/EC reinforced concrete beams demonstrated comparable performance to standard reinforced concrete beams, with negligible effects on bending performance, crack spacing, and maximum crack width. This study provides valuable insights for the practical application of rGO/EC in enhancing the durability and longevity of reinforced concrete structures.

Abstract3D concrete printing is an advanced technology offering numerous benefits, including design flexibility, higher construction efficiency, and reduced labor cost. However, the unique processing requirements necessitate careful consideration of the quality of 3D‐printed concrete. To this end, this study developed a real‐time visual inspection method to quantify geometrical and surface quality metrics, integrating rheological parameters for enhanced accuracy. Three binder‐to‐sand ratios (0.6, 0.8, 1) and sand fineness moduli (2.5, 2.9, 3.3) were tested. We began by comparing various image processing technologies, followed by analyzing the geometrical contour and surface defects from a top‐down perspective. Results showed that increasing the binder‐to‐sand ratio from 0.6 to 1 and reducing the sand fineness modulus from 3.3 to 2.5 reduced defect area ratios by up to 98% (from 4.3% to 0.041%). Subsequently, we integrated rheological parameters to refine the image analysis results and validated the approach through three case studies. The results demonstrate that the developed visual inspection technology effectively assesses the quality of 3D‐printed concrete, ensuring precision and reliability in evaluating 3D‐printed structures.