International Journal of Steel Structures最新文献

This work covers the validation results of a two-stage approach for the analysis of axially loaded tee-stub connections. It is devoted to the analysis of the load-deflection curves of type-11 failure mode tee-stub connections by means of an elegant alternative to existing closed-form solutions. The tee-stub connections and the relatively simple and easy-to-use polynomial relationships of the closed-form solution are proposed in a companion paper. The computed results are compared with experimental values available in the literature. The effectiveness and degree of accuracy of the closed-form solution is discussed and guidelines are provided as to the extent of their applicability. Two key-geometric factors are also introduced to make the approach more conclusive. The approach, along with the geometric-based factors and the design guidelines, provide a suitable basis for the design and analysis of type-11 failure mode tee-stub connections and considerably facilitate the day-to-day practising engineers in reproducing the axial load-deflection response with good accuracy. EC3 is widely referenced.

The proliferation of super-tall buildings with complex interconnected forms presents significant challenges for wind-resistant design, often exceeding the prescriptive scope of modern building codes. This paper presents a comprehensive evaluation of the wind performance of a super-high-rise triple-tower building interconnected at its upper levels. Dynamic pressure measurements from wind tunnel tests were integrated with a detailed finite element model, and subsequently processed through a custom-developed software platform which automates the entire analysis workflow from raw data handling to the determination of structural responses via frequency-domain analysis. The results reveal complex aerodynamic interference, with wind pressure coefficients on the interconnected floors exhibiting substantially greater volatility compared to those on isolated tower sections. The analysis of wind-induced responses indicates that the equivalent static wind loads display a distinctly non-linear distribution with height, particularly around the interconnected zone, deviating significantly from code-specified profiles. Despite these aerodynamic complexities, the peak top-floor accelerations and inter-story drift ratios were found to remain within the established serviceability limits for all wind directions. This study provides crucial insights into the wind-structure interaction of complex multi-tower systems and demonstrates the efficacy of an integrated platform for enhancing the accuracy and efficiency of their wind-resistant design.

This study experimentally investigates the cyclic behavior of semi-rigid beam-to-column angle connections using carbon steel (SS275), austenitic stainless steel (STS316), and low-yield-point steel (HSA80), to quantify the influence of material properties on structural performance. Six specimens, including top-and-seat (C-TS) and top-and-seat with double web angle (C-TSDW) configurations, were tested under cyclic loading. Material tests showed that STS316 has approximately 10% lower elastic modulus and 27% lower yield stress than SS275, but higher ductility (1.54 times) and strain-hardening capacity (1.70 times). Despite this, the STS316 connections exhibited only a 16% reduction in yield moment, with comparable moment resistance at large deformations (moment ratios of 0.96 and 1.04 at 0.02 rad and 0.04 rad, respectively) and similar energy dissipation capacity at 0.04 rad. The HSA80 connections showed higher initial stiffness and strength primarily due to increased angle thickness, along with stable inelastic behavior. The C-TSDW configuration exhibited 20–25% higher energy dissipation and improved ductility compared to the C-TS configuration. These results indicate that connection-level performance is governed more by connection configuration and deformation capacity than by material yield stress alone.

With the increasing demand for seismic resistance in high-rise and long-span structures, conventional buckling-restrained braces (BRB) face limitations such as a single energy dissipation mechanism. This study proposes a novel buckling-restrained brace featuring a negative Poisson’s ratio (NPR) effect and a spindle-shaped truss restraint. A finite element model of the BRB was developed, and its elastoplastic bearing capacity and hysteretic behavior were investigated using finite element software. A design method based on the threshold constraint ratio of the energy-dissipative BRB was proposed. The elastic buckling performance of the brace was examined, yielding a theoretical formula for the elastic buckling load and an expression for its constraint ratio. Variations in the constraint ratio were used to analyze the elastoplastic bearing capacity under monotonic axial compression and the hysteretic behavior under cyclic loading, investigating the brace’s instability modes, ultimate load capacity, and energy dissipation performance. The threshold constraint ratio of the brace was determined, providing a basis and methodology for the design of this innovative BRB. Results demonstrate that the unique mechanical properties of the NPR structure, particularly its anomalous lateral expansion under axial compression, create a self-reinforcing radial restraint mechanism, effectively suppressing local buckling tendencies observed in conventional braces. The integrated design eliminates slippage issues inherent in traditional decoupled systems, enabling the truss restraint to respond in real time to core deformation. The spatial truss effect of the spindle-shaped components ensures uniform three-dimensional stress distribution, with a threshold constraint ratio of 3.82 for the energy-dissipative brace.

Global urbanization and transportation acceleration have heightened the collisions risk of vehicle on concrete filled steel tube (CFST) columns. The catastrophic fracture failure in structural column might ultimately cause the entire structure to collapse. Machine learning technologies were created in this work to forecast CFST lateral deflection and identify failure modes (bending deformation, crack and fracture failure). A database comprising 875 samples was constructed to create Gaussian process regression, Least-Squares Boosting, Random Forest, Support Vector Machine (SVM), Multilayer Perceptron (MLP), Long Short-term Memory, Naive Bayesian Classifier and k-Nearest Neighbors algorithms. MLP delivered the most accurate prediction of deflection with a correlation coefficient of 0.95, while SVM performed the best in classifying failure modes with an accuracy of 0.81. Shapley additive interpretation was used to analyze feature importance, it was discovered that geometric dimensions exerted greater effect on model output than material attributes. Finally, this research developed an intelligent application and provided a visual presentation of predicted results, which provides a promising, user-friendly and time-saving tool for investigating intricate impact response.

This paper proposes a bridge structural assessment method based on the regression surface area of the dissipation coefficient ((eta )), integrated with Bayesian deep learning (BDL) to optimize vibration signal analysis. With advances in sensor technology, high-precision vibration data can now be collected; however, traditional methods have not fully exploited the potential of these data. The study uses the dissipation coefficient ((eta )) to evaluate structural degradation based on elasticity and viscous damping properties. Instead of relying solely on statistical indicators such as mean and coefficient of variation (CV), this research introduces the surface area ((S)) of the regression plane as a comprehensive metric, offering a more detailed depiction of structural deterioration. In addition, the paper develops an artificial neural network that converts vibration measurement data into a rating scale from 1 to 10, allowing real-time monitoring of structural conditions. The proposed method was tested on the Saigon Bridge and Song Than Bridge, demonstrating its ability to accurately reflect structural degradation over time and the effectiveness of maintenance interventions. The results indicate that this approach not only provides detailed insights into the structural degradation process, but also facilitates automated monitoring and informed decision making in infrastructure maintenance.

Beams are fundamental structural components used in various engineering disciplines. In civil engineering, they are subjected to various loading conditions, particularly mechanical and thermal loads. Understanding their structural behavior under thermal conditions is crucial for designing components and preventing structural failures. This paper examines the structural response of a prismatic SS304 steel beam with both ends clamped, subjected to non-uniform temperature variation along its depth, using experimental and 3D finite element analysis. The structural response of a clamped beam is assessed by investigating the variation of normal and shear stresses along its longitudinal and depth directions. Additionally, the impact of non-uniform temperature changes on the deflection of beams with different cross-sections is examined using an experimental method. This numerical analysis revealed that under linear temperature variation, both ends-restrained beams experience minimal deflection, zero shear stress, and normal stresses that vary linearly along the beam’s depth. The deflection increases with decreasing cross-section sizes of the clamped beam under both linear and non-linear temperature variations. The finite element analysis underestimates the deflection by 20% compared to experimental results under a higher temperature gradient. The deflection under nonlinear temperature variation is 55%, 36%, and 38% higher than under linear temperature variation for the 20 × 20, 15 × 15, and 10 × 10 cross-sections, respectively.

Embedded part systems with orthogonal anchor bars are required at the connection joints between buckling-restrained braces (BRBs) and concrete beam-columns to transfer the brace capacity to the main structure. The calculation method for the internal force of anchor bars in this type of embedded part is still underdeveloped. Based on the actual beam-column and brace joints in engineering projects, bearing capacity tests were conducted. Through the analysis of test results, the failure mode of the embedded part system with orthogonal anchor bars was revealed. According to the characteristics of embedded parts, the anchor bars were simplified as spring elements. A mechanical analysis model was established, and method for calculating the internal force of anchor bars was proposed. To supplement the untested content in the experiments, a refined finite element model was built, and its accuracy was verified using the test results. The finite element analysis results confirm the accuracy of the proposed internal force calculation formula for anchor bars. The results show that the uniform force method has a significant error used in calculation of anchor bars forces, while the calculation formula of this study have significantly improved accuracy.

Metal roofing systems are extensively used in long-span spatial structures due to their lightweight properties. However, their complex connection details make joints particularly susceptible to failure under strong winds, leading to wind uplift damage. In this study, a full-scale wind uplift resistance test was conducted on the prefabricated metal roofing system of Hangzhou Asian Games Esports Center, and found that the local damage and failure first occurred at the L-shaped connection joints connecting the roof panels and the secondary purlins. In order to comprehensively investigate the deformation and failure modes of the L-shaped joints under wind loading, a full process loading test was carried out on the joints. Simultaneously, a comparative study was conducted using the finite element method. The test and analysis indicate that the failure mode of the joint is that the weak cross-section of the L-shaped joint yields first, resulting in an out of plane “bulging” phenomenon and gradually separating the upper and lower parts of the joint. Quantitative results show that the average ultimate bearing capacity of the standard joint is 2.04 kN. The joint enters the plastic stage at approximately 1.0 kN, and severe buckling failure occurs when the load exceeds 1.3 kN. Based on these observations, this study develops a simplified mechanical model for calculating wind uplift capacity and proposes a practical design verification method for these L-shaped connection joints.

Cold-formed steel (CFS) lipped channel beams are widely used in building construction because of their high strength-to-weight ratio and ease of fabrication. In practice, web openings are introduced to accommodate mechanical, electrical, and plumbing services, which can change the stiffness, buckling response, and ultimate capacity of these members. Previous research has mainly considered circular and rectangular web openings and has given limited attention to other opening shapes and web stiffening details. This paper presents a nonlinear finite element study of cold-formed steel lipped channel beams with different web opening configurations, including circular, square, hexagonal, and hexagonal openings with web notches. The beam models were developed in ANSYS Mechanical APDL using a bilinear elastic–plastic constitutive law and large deformation analysis. The model was verified with published experimental and numerical results and predicted the ultimate load within about 8 percent of the test values. A parametric study of 128 beams was then carried out to examine the effects of opening shape, opening size, web thickness, span length, and web notches on load–deflection behavior and failure modes. The results showed that beams with hexagonal openings have higher strength and lower deflection than beams with circular or square openings, while hexagonal openings with notches further increase the ultimate load. The findings provide practical guidance for the design and optimization of perforated cold-formed steel beams.