Probabilistic safety assessment of the shear-friction and strut-and-tie methods for designing reinforced-concrete corbels according to ACI 318–19

Influence of concrete type on the structural performance of timber-concrete composite T-beams using adhesively bonded perfobond connections: experimental and analytical evaluation

A formulation integrating the code recommendations for the design of steel fiber reinforced concrete (SFRC) beams with redundant supports

An experimental program was conducted to evaluate the effectiveness of replacing conventional reinforcement by steel fiber reinforcement in the hogging region of continuous shallow beams (with redundant supports). Seven groups of steel fiber reinforced concrete (SFRC) continuous shallow beams were tested under flexural loading, simulating a strip of a slab supported by three aligned piles or columns. The tests also aimed to assess the influence of different ratios of conventional reinforcement in both sagging and hogging regions, under serviceability and ultimate limit state conditions (SLS and ULS, respectively). The results of this experimental program are used to assess the predictive performance of an analytical model for the design of SFRC beams of redundant support conditions. This model is based on the flexibility method and considers the moment‐curvature relationship to derive the flexural stiffness during the loading process of a SFRC beam. The moment‐curvature is determined by using the recommendations of the Model Code 2020 (MC2020) and the Eurocode 1992‐1‐1 (EC2). The predictive performance of the developed approach is assessed on the serviceability and ultimate limit design verifications considering the results from the experimental program. When using average values for the material properties, the analytical model using both the MC2020 an EC2 provided overpredictions in terms of load carrying capacity for SLS and ULS design verifications (up to 57% and 38%, respectively, in terms of normalized error). When using characteristic values, the overprediction was limited to 31% with the MC2020, while over‐ and under‐predictions were obtained with EC2, limited to 25%. By applying the Estimation of the Coefficient of Variation method, safe predictions were obtained using MC2020 and EC2 formulations. It was verified that normalized error of the average crack width was less than 18% when using MC2020 and EC2 formulations. Finally, numerical studies were conducted on statically indeterminate shallow beams to assess the influence of both beam scale and the replacement of conventional tensile reinforcement by fibers at the intermediate support on the ULS and SLS design verifications.

Influence of joint load-bearing behavior on the system-level response of reinforced-concrete truss-like beams: topology optimization basis

Structural optimization can reduce material use and embodied carbon in reinforced concrete (RC) beams, but the removal of concrete creates truss-like load paths in which local joint behavior may strongly influence stiffness, force redistribution, and failure development. This study investigates the mechanical behavior of joints in reinforced concrete truss-like beams and evaluates how different joint geometries influence the transfer of moment, axial force, and shear between connected members. The research combines experimental testing, calibrated nonlinear finite element analysis (FEA), and isolated joint simulations. Two beam configurations, namely, Warren truss with 45° diagonals (W45) and Warren truss with verticals and 45° diagonals (W45-V), were tested under three-point bending and used to calibrate the numerical models. The calibrated FEA approach was then extended to four truss-like configurations: W45, Warren truss with 60° diagonals (W60), W45-V, and Pratt truss with 45° diagonals (P45). In addition, 66 isolated joint models were analyzed using unit rotation, axial displacement, and shear displacement to quantify moment, axial-force, and shear transfer between connected members. The results show that the investigated joints behave nonlinearly and asymmetrically, with clear stiffness changes after cracking. None of the joints behaves as an ideal hinge; instead, all configurations transfer moments, axial forces, and shear through semi-rigid joint action. W60 shows a stiffer and more direct force-transfer mechanism, W45-V provides improved redistribution through vertical members, and P45 exhibits the strongest directional dependence. Overall, member-only verification is insufficient, and simplified design should include semi-rigid joint behavior and local joint verification.

Experimental investigation on the behavior and strengthening of opened joints in stepped reinforced concrete beams using CFRP, steel plates, and NSM reinforcement

This study experimentally investigates the structural behavior of reinforced concrete (RC) stepped beams with opened joints, commonly used in sloping roofs, ramps, and stairs. Unlike conventional beams, stepped beams develop combined axial force and bending moment at the joint, resulting in complex normal and shear stress interactions. The experimental program comprised two phases: Phase I examined the effect of reinforcement detailing on performance, while Phase II evaluated three strengthening techniques—externally bonded CFRP sheets, steel plates, and near-surface mounted (NSM) steel bars—on six beams. Results showed that proper reinforcement detailing, particularly extending to the upper joint edge, significantly enhanced ultimate load and ductility, whereas insufficient development length reduced performance. Among strengthening techniques, steel plates provided the highest improvements in ultimate load (up to 69.7%) and ductility, while NSM bars were least effective. The most efficient configuration used 100 mm wide, 2 mm thick steel plates. Strengthening also reduced vertical deflection and horizontal displacement. Cost–benefit analysis indicated steel plate strengthening as the most economical solution. The study highlights the critical role of joint reinforcement detailing in stepped beams and demonstrates the effectiveness of targeted strengthening techniques in restoring and improving structural performance.

Enhancing Shear, Flexural, and Torsional Performance of RC Beams Through Advanced Mesh Wrapping Techniques: A State-of-the-Art Review

Many RC structures are deteriorating due to aging, increased service loads, environmental deterioration, corrosion of the reinforcement, and design deficiencies. Therefore, strengthening and retrofitting techniques are essential to improve the performance of RC structures. A promising method for strengthening RC structures is by using fiber-reinforced polymer composites because of their specific strength, rust resistivity and ease of application in construction. Currently, mesh-based reinforcement systems have emerged as an acceptable alternative to conventional FRP sheets based on improved bonding characteristics, improved crack-resistant performance and improved stress redistribution. A systematic review was performed to investigate mesh-induced strengthening techniques for the RC beams under combined shear, flexural and torsional loading conditions. A total of 52 studies published between the years 2000 to 2026 were included for analysis from a variety of databases. The studies were categorized based on the strengthening materials used, wrapping configurations, loading conditions, and performance indicators such as load-carrying capacity, ductility, torsional capacity, crack prevention and energy absorption. The conclusion of the review indicates that while GFRP systems show greater ductility and are usually less costly, CFRP systems typically result in the largest increases in loading capacity. Hybrid FPR systems utilising carbon and glass fibers produced a balanced performance by increasing both loading and deformation capacity. The performance characteristics for strengthening have a direct bearing on how the RC beam behaves. Overall, the inclusion of mesh in the construction improved strengthening techniques and shows strong potential for enhancing the efficiency and durability of RC beams under complex loading conditions.

Reliability Calculation and Analysis of Influencing Factors for Girth Welds in High-Grade Steel Pipelines Based on HMC-SS

Fracture failure of girth welds in high-grade steel pipelines poses a critical threat to pipeline integrity. Leveraging enhanced digitalization in pipeline engineering, a statistical database has been developed to support reliability analysis based on actual operational data. This study utilizes real project data to analyze the failure probability and key influencing factors of girth welds containing crack defects, thereby providing theoretical support for safety design and risk management. To overcome the conservatism of traditional deterministic methods, a probabilistic reliability model was established, incorporating a modified PRCI-CRES ultimate tensile strain criterion. Addressing the inefficiency of standard Monte Carlo (MC) simulation in high-dimensional low-probability contexts, an efficient Hamiltonian Monte Carlo-Subset Simulation (HMC-SS) strategy was introduced. Results show that HMC-SS improves computational efficiency by 99.95% over MC, with only 0.90% relative error. Key findings include: crack depth has the strongest influence – variation from 0.92 mm to 3.68 mm, which increases failure probability by 103 times; the strength matching coefficient is dominant, and higher values reduce failure risk; strain demand exhibits a positive correlation with failure probability and couples with material properties. It is concluded that high- or equal-strength material matching should be emphasized in welding, and reliability-informed design should account for multi-parameter interactions to ensure global safety.