International Journal of Steel Structures最新文献

In this paper, an innovative Shear-Bending Yielding Damper (SBYD) is proposed to overcome the limitations of conventional metallic yielding dampers. They commonly suffer from premature buckling, stress concentration, and limited energy dissipation capacity. The SBYD integrates a centrally positioned shear plate with symmetrically arranged K-type bending plates to achieve dual-stage yielding and provide continuous out-of-plane restraint. Finite element analysis was performed on eight optimized configurations (SBYD1-SBYD8) using ABAQUS, and the results were compared with those of a traditional rectangular damper. The simulations demonstrated that the combined shear bending mechanism significantly enhanced cyclic stability, hysteretic response, and deformation capacity. The optimized configuration SBYD7 (10 mm shear plate; 24 mm bending plates) delivered the best overall performance, achieving 36% higher energy dissipation and over 65% reduction in out-of-plane buckling relative to the baseline specimen. Although SBYD8 showed the highest absolute strength, its material cost was not less efficient. Frame-level analyses further confirmed that installing SBYDs substantially reduced lateral displacements, inter-story drift, and internal force demands during seismic loading. Overall, the proposed SBYD provided a robust, economical, and highly effective energy-dissipation mechanism suitable for both new construction and seismic retrofitting.

Previous studies on steel–concrete composite beams have largely focused on hot-rolled steel sections with welded shear connectors, for which full interaction is commonly assumed. In contrast, cold-formed steel–concrete composite beams employing mechanically fastened shear connectors often show partial interaction due to connector flexibility and thin-walled steel behavior. This study investigates the structural response of composite beams incorporating novel screw-fastened inverted U-shaped flexible shear connectors through an experimental programme. Pushout tests were first conducted to characterize the nonlinear load–slip behavior of the connectors. Three full-scale composite beam specimens with varying cold-formed steel section depths and thicknesses were then tested under four-point bending to examine the influence of these parameters on deflection, ultimate load-carrying capacity, serviceability and failure modes. Increasing the beam depth and steel section thickness increased the ultimate load-carrying capacity while reducing beam deflection, whereas connector flexibility promoted early interface slip and partial interaction, making serviceability behaviour the governing design consideration. The ultimate capacity of the beams was governed by local web buckling of the thin-walled steel section and cracking of the concrete slab, rather than connector failure. The study shows that the behavior of cold-formed steel composite beams with flexible shear connectors is serviceability- driven and strongly influenced by connector deformability and thin-walled instability.

The demand for steel–timber hybrid structures is increasing, particularly in mid- and high-rise buildings. In such systems, connection hardware plays a critical role; however, its high thermal conductivity may introduce vulnerabilities at joints under fire conditions. To address this issue, this study evaluates the temperature distribution of connection hardware protected with fire-resistant coatings using finite element analysis (FEA). Based on previous studies, five analytical models were developed, considering key variables such as the presence of connection hardware, the application of fire-resistant coating, and coating thickness, all subjected to a 3-h standard fire exposure. The results show that connection hardware accelerates the formation of the char layer at steel–timber joints. However, the application of fire-resistant coating significantly reduces the charring rate and depth of timber, thereby improving fire performance. As the coating thickness increases, the development of the char layer is delayed, resulting in a larger residual cross-sectional area. In particular, for specimens with a 15 mm coating, the steel temperature remained below the critical threshold throughout the 3-h exposure, indicating that a 3-h fire resistance rating can be achieved. Furthermore, by evaluating the charring depth over time, this study demonstrates that a more refined fire resistance assessment can be achieved compared to conventional approaches.

This study investigated the feasibility of replacing the conventional galvanized steel plate SGH440 with the new high-strength galvanized steel plate S450GD for the silo wall of prefabricated steel silos. Multiple sets of axial tensile tests were carried out on high-strength bolted connections of corrugated steel plates, with steel grade, plate thickness, and number of bolts as the test variables. The number of bolts was specifically altered to study the bolt group effect on the bolt shear-bearing capacity. The test results indicate that the mechanical properties of both steel grades meet the requirements of Chinese standards, and the replacement can reduce steel consumption while ensuring safety. The shear strength value for a single high-strength bolt specified in Chinese standards is overly conservative, whereas the bolt hole bearing strength is reasonable. During loading, the strain values at wave crests and wave troughs differ, and the net-section tensile failure of the specimens initiates from the center and propagates towards the edges. When bolt shear failure occurred, the bolt group effect reduced the actual bolt shear-bearing capacity by approximately 20%, accordingly, an engineering recommended value of the effective bolt number coefficient η = 0.79. A systematic comparison of the applicability of Chinese, American, and European codes reveals that Eurocode 3 is the safest and most economical when considering the bolt group effect. A balanced design criterion for high-strength bolted connections of corrugated steel plates is also proposed. Therefore, an economical and reasonable connection design should strive to make the net-section tensile capacity as close as possible to the bolt shear-bearing capacity or the bolt hole bearing capacity. These findings are expected to provide a theoretical basis for the design of prefabricated steel silos and serve as a reference for the revision of relevant design specifications.

In this study, a novel plasma-MIG hybrid welding was used to optimize the geometry of stainless steel (SS) and low carbon steel butt joints by combining the Taguchi method and grey relational analysis (GRA). In the experiments, the optimal parameters were obtained for single objective and multi-objective respectively. The results of applying the grey-based Taguchi method are better than the experimental results of applying the Taguchi method alone. From the analysis of variation (ANOVA), the plasma and MIG current are important factors affecting the quality characteristics, with higher plasma current increasing penetration of weld bead. In this hybrid welding process, higher travel speeds of welding torch can lead to undercuts, while increasing the carbon dioxide content in the argon shielding gas can lead to more spatter on the specimen surface. The tensile strength of the specimen produced through multi-objective optimization was 461.52 MPa. All tensile test results indicate that undercuts on the SS side does not affect the fracture location, and Y-type grooves offer better crack resistance than I-type grooves. This study proves that the grey-based Taguchi method can obtain better tensile strength and improve the geometry of SS and low carbon steel butt welds.

Hybrid beam-column joints are increasingly used in precast concrete as alternatives to traditional corbels and nib beam-column joints. While these joints offer several advantages, their semi-rigid behaviour makes them more susceptible to deflection under low loads and cracking during fire exposure. This study investigates the fire resistance of an embedded steel corbel beam-column joint, building upon prior research. Two test specimens were exposed to ambient conditions and a standard ISO 834 standard fire curve for 120 min. Results show that the embedded steel corbel heats more slowly, reaching 300 °C at 165 min, compared to 105 min for the monolithic sample. The peak temperature for the embedded steel corbel was 1053 °C. At elevated temperatures, the joint exhibited a reduction in moment capacity of 25.7 kNm, a 6.7 milliradian increase in rotation, and approximately 26% reduction in load-bearing capacity. These results raise concerns about the joint’s long-term stability and thermal fatigue under fire conditions. Furthermore, the semi-rigid behaviour of the steel corbel joint complicates its modelling as either rigid or pinned in structural analyses. The results demonstrate that while the embedded steel corbel delays crack initiation and thermal transmission, it experiences greater degradation in moment and load capacity under fire exposure compared to the monolithic configuration, highlighting the trade-off between crack control and global stiffness performance in hybrid beam–column joints subjected to elevated temperatures.

Cold-formed steel (CFS) shear walls have gained importance as lateral load-resisting systems in modern structural design, especially for low and mid-rise buildings, owing to their high strength-to-weight ratio, ease of fabrication, and rapid construction. Despite the growing volume of experimental and numerical research in this area, the existing literature remains fragmented, with most studies examining individual design parameters in isolation, and no unified framework exists for simultaneously predicting multiple performance metrics. The study has two main objectives. First, it aims to comprehensively review recent experimental and numerical research on cold-formed steel shear walls, examining the key parameters that influence their structural performance under seismic and wind loading, including sheathing type, framing thickness, connection detailing, wall configuration, and fastener spacing. Second, based on the findings of this review, it aims to develop a machine-learning based predictive framework using these key influencing parameters to predict the strength, stiffness, and ductility of CFS shear wall panels under varying design conditions, and to build a consolidated database for CFS shear wall systems. The limitations of the conventional designs are addressed, and emerging solutions, including infilled, composite, and centrally sheathed systems, are critically examined. Among the various sheathing materials tested, corrugated steel sheathing proved to be the strongest choice for seismic applications. At the same time, fibre cement board showed excellent energy absorption, and particle cement board notably improved peak load capacity. Using hexagonal-head screws with washers spaced at 100 mm or less improved connection performance and prevented early failure. CFS framing thicknesses of 1.3–1.8 mm, when paired with thicker sheathing, delivered better overall seismic reliability. Current design codes, including AISI and FEMA provisions, were found to lack adequate guidance for configurations involving newer sheathing materials and optimised fastener layouts. Based on these findings, a machine-learning based predictive framework is proposed using key influencing parameters to predict the strength, stiffness, and ductility of cold-formed steel wall panels under varying design conditions and to develop a database for CFS shear wall systems. The findings also provide recommendations for future research and contribute towards the development of standardised design practices.

Recently, significant research has focused on developing durable and resilient solutions for highway bridge construction and rehabilitation worldwide. Among these, prefabricated composite girders with innovative deck-to-girder non-interference interface connections have been proposed to enhance constructability by removing on-site obstacles. In this study, finite element modeling of the deck-to-girder non-interference interface connections was set up to simulate the interface properties which are verified through recently conducted experimental study results of the monolithic-scale test. A series of numerical parametric studies were performed to investigate the effect of interface properties on the structural behavior of prefabricated composite girders with deck-to-girder non-interference interface connections. By protecting the transverse deck rebars that take more significant role to hold the deck flexural strength, loop type interface intercrossing rebars have been adopted to secure a higher performance non-interference connections. The interactions and correlations of the interface surface properties and the loop-type inter-cross rebars have been thoroughly investigated through a series of parametric studies. It was found from the parametric studies that the loop-type interface rebars can minimize the impacts on the transverse deck reinforcements due to critical shear plane actions even though 50% lower friction or cohesion capacities would be assumed. Thus, it is simultaneously proved that the influence on the flexural behavior of prefabricated composite girders like this case was minimal, when the lower limit range of interface properties such as stiffness coefficient, peak value of traction, and effective separation in case of complete failure was applied. Since it has been seen that the ultimate strains in the loop reinforcement rebars can reach beyond the yield strain states in the lower case of friction capacity, indicating that slip increases, thereby affecting the stiffness of the girder. The management of non-shrink hydraulic injection grout is important. This study suggests a desirable simulation and approach of such interface surfaces to evaluate the structural behaviors and nominal resistances of the prefabricated and assembled girders.

Benchmark problems are essential for evaluating structural optimization algorithms, yet most studies still rely on the classical 120-bar dome, a simplified, idealized geometry. This over-reliance restricts the generality and practical relevance of optimization research on spatial structures. To address this gap, this study introduces three alternative geodesic benchmark models (tetrahedral, octahedral, and icosahedral domes) developed under a unified modeling protocol and AISC–ASD design constraints. Six metaheuristic algorithms [Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Differential Evolution (DE), Grey Wolf Optimizer (GWO), Artificial Bee Colony (ABC), and a hybrid GA-PSO] were applied within an equal-budget framework across four design scenarios: stress-only, combined stress and lateral deflection, vertical-deflection-only, and fully constrained cases. The proposed benchmarks consistently produce lighter optimal designs than the 120-bar dome under identical conditions, confirming their structural efficiency and suitability for algorithm testing. Rather than ranking algorithms, this work establishes a reproducible, constraint-consistent benchmark suite that enables fair comparisons among optimization methods and provides a richer foundation for future research in structural and metaheuristic optimization.

The building sector is a major contributor to global greenhouse gas (GHG) emissions. Despite their high carbon intensity, reinforced concrete slabs are among the most widely used structural elements. In pursuit of more sustainable and cost-efficient floor systems, this study presents a comparative assessment of conventional reinforced concrete slabs and composite steel deck slabs for one-way floor applications. The comparison focuses on embodied carbon and construction cost, which are two critical indicators of sustainable design decision-making. The methodology involved designing slab alternatives for varying spans (2–4 m) and live load intensities (2.5 and 5.0 kN/m²) in accordance with relevant structural codes. The material quantities were determined from the structural design outputs and used to calculate the embodied carbon following a cradle-to-gate framework (BS EN 15978). A cost analysis was conducted using the prevailing Indonesian unit prices for concrete, steel reinforcement, and the profiled steel decks. A sensitivity analysis was also performed, incorporating ± 20% variations in the concrete carbon factors and steel unit prices to evaluate the robustness. The results revealed that reinforced concrete slabs are competitive at short spans, offering slightly lower embodied carbon and costs. However, at medium and long spans (≥ 3 m), composite slabs outperform reinforced concrete alternatives by simultaneously reducing the embodied carbon and cost. The sensitivity analysis confirmed the robustness of these findings under realistic variations in material properties and prices. This study demonstrates that composite steel deck slabs are structurally efficient, environmentally favourable, and economically viable solutions for medium- to long-span floor systems, offering a practical pathway toward sustainable construction practices.