International Journal of Steel Structures最新文献

A large number of concrete-filled CFRP steel tube structures are widely used in practical engineering at current. Considering that as a column structure, compressive-shear loading is a more important bearing capacity method. 12 specimens are designed to study the comperssive-shear performance of concrete filled CFRP steel tube. The shear loading- displacement (V-Δ) curves and the collaborative work performance between the steel tube and CFRP are tested. Based on the tests, a numerical simulation method is firstly proposed to estimate the compressive-shear performance of concrete-filled CFRP steel tube stub column, and then validated against the representative tests results.Parametric study is conducted to explore the influence of principle factors on compresive-shear behaviour by verified numerical models. The experimental results show that the steel tube and CFRP can work together. As the axial compression ratio increases, the shear displacement of the specimen is constrained, resulting in increase of bearing capacity. Additionally, the increase of steel ratio, CFRP layers and materials strength for specimens enhance not only the bearing capacity but also the initial stiffness. The simulation results of the established finite element model are in good agreement with the experimental results. Finally, Based on experimental and finite element results, the bearing capacity correlation equation for concrete-filled square CFRP steel tublar stub columns when subjected to compressive-shear loading is presented.

This study introduces a new MATLAB subroutine designed to simplify a rigid-plastic model for analysing the dynamic response of steal beam under blast loading. The numerical framework integrates a Linear Complementarity (LC) model to evaluate the impact of loading on skeletal structures. The study aims to enhance the computational, algorithmic and numerical stability of this robust procedure while assessing the response of steel beams subjected to blast loading conditions. The computational results are then validated using experimental and computational examples. The first example seeks a theoretical solution for a steel beam exposed to a uniformly distributed triangular pulse load of varying magnitudes, presenting and contrasting both numerical and theoretical outcomes. In the second example, far-field blast experimental and computational results are compared with predictions from the LCP model. The findings illustrate a strong alignment between the model and experimental data documented in existing literature.

This study aimed to investigate fracture behavior of electroslag welding (ESW) joint with 590-N/mm² class steel using numerical analysis, covering a range of material scales in the structural level. The extended Mohr–Coulomb (EMC) fracture criterion was employed for finite element analysis (FEA). Uniaxial tensile test and three-point bending test were conducted to analyze the fracture behavior from the material scale and calibrate the fracture criterion. The test specimens consisted of the base metal, heat-affected-zone metal, and welding metal obtained from an ESW joint with a 590 N/mm² class steel. Subsequently, FEA was conducted for a biaxial tensile test to investigate fracture behavior at a structural scale and verify the feasibility and accuracy of the calibrated fracture criterion. The comparison between the results from the FEA and test suggests that the FEA based on the EMC fracture criterion can accurately predict fracture behavior but tends to overestimate the bearing capacity. Thereafter, the effect of axial force on column was quantitatively investigated. The results suggest that the existence of tensile axial force at column decreases the ductility of ESW joint and shifts the fracture locus from the welding metal to heat-affected zone. However, the force has minimal influence on the pop-in load. Finally, the feasibility of applying the current Japanese specifications designated for the 490 N/mm² class steel for the 590 N/mm² class steel was examined. The results indicate that the provision can serve as a safe and reliable guideline for the 590 N/mm² class steel as well.

The analysis and research of composite structure specimens depend on test methods. However, due to the high cost, complex test conditions, time-consuming, and other problems, it is difficult to carry out a large number of tests. A large amount of data is often required for parametric analysis and structural optimization of composite structure specimens. Therefore, to solve the problem of insufficient data samples in the analysis and research of specimens. In this paper, a finite element model updating method based on Bayesian theory and a Gaussian process data fusion method is proposed, that is, the amount of data is expanded by the proposed model updating method, and then the experimental and numerical simulation data are fused based on the Gaussian process data fusion method. Finally, the effectiveness of the proposed model updating method and data fusion method is verified by a numerical example of π type beam-column joints. The results show that the method has high generalization ability and prediction accuracy in the case of small samples through the fusion of numerical simulation and experimental data.

Connections between concrete filled members are common in tall buildings, bridges, and offshore structures because of their robust structural performance. While extensive research has been done on isolated concrete-filled structural members, relatively little research has been conducted on composite connection regions. This article first describes a database on experimental/analytical investigations on concrete-filled connections comprising 135 tests. It then develops a generic numerical model capable of capturing the entire range of behavior of these connections, including local buckling of the steel tubes and friction/contact resistance between steel and concrete. The model was calibrated against a single test and its performance was verified against three other very different tests. The results indicate that the four models can track well the strength and stiffness of the specimens up to ultimate and predict well different failure patterns. Comparisons of the experimental and numerical load-deformation curves show very good agreement in predicting the strength and deformations at which different behaviors arise, and that performance is controlled primarily by both the strength of the concrete and the confinement effect of the steel tube in the connection area.

Mounting 5G antennas on existing power transmission towers can meet the needs of both power supply and 5G communication. Current mounting techniques have the problems of cumbersome process and slow efficiency. This research designs a new type of mounting device of 5G Antenna on power transmission towers. The components and the installation process of this mounting device are introduced, the stress behavior of the mounting device under self-weight load, ice load and wind load is studied through finite element analysis (FEA), and the safety of the mounting device under self-weight load, ice load and wind load is verified through experiments. Furthermore, the safety of power transmission towers is evaluated after 5G antenna is mounted under environmental loads. The results show that: (1) the wind load has the dominant effect on the 5G mounting device, and the proportion of stress caused by wind load is between 89–97%; (2) FEA and experiment show that all the stresses of the device components do not exceed the yield strength limit 355 MPa, indicating that the mounting device is safe to support the 5G antenna under gravity, ice load and wind load; (3) the displacements and stresses of power transmission towers will increase after 5G antenna is mounted, but the values do not exceed the limit, indicating that the power transmission towers are still safe for operation after 5G antenna is mounted.

Because of recent enhancements to fatigue strength regulations in Korea, an analytical and experimental study was conducted to assess the fatigue performance of KR-type rail clips. Given the intricate shape and stress distribution of rail clips, accurately measuring stress at potential fatigue crack locations proves challenging. Hence, the finite and infinite life fatigue strengths of the rail clip were evaluated based on the displacement induced by train wheel passage, as opposed to stress. A test setup, capable of testing eight rail clips simultaneously, was developed. Fatigue tests across six displacement ranges from 1 to 4 mm identified a potential fatigue limit at a 2 mm displacement range for the KR-type rail clip. This proposed fatigue limit was analytically validated using the Smith–Watson–Topper method. Two distinct fatigue failure modes, consistent with finite element analysis findings, were observed. Additionally, a displacement range-based fatigue life equation, predicting a 5% probability of failure, was proposed.

Reducing residual deformation of shear links and enhancing structural self-centering performance are two effective strategies to optimize the seismic resilience of Y-eccentrically braced frames. Based on the aforementioned concepts, a novel self-centering Y-eccentrically braced frame structure which composing of self-centering joints and slip connection shear link was introduced in this study. Firstly, a design methodology for the slip connection shear link and anticipated mechanical properties of the novel structure were proposed through theoretical analyses. Subsequently, finite element models were established based on previous experimental data to investigate the lateral load behavior of the novel structure by comparing it with a conventional structure. The results indicate that when possessing sufficient lateral load capacity and energy dissipation capacity, the novel structure exhibits exceptional self-centering performance. Finally, the energy dissipation and self-centering mechanism were obtained by conducting stress analysis on substructures under various seismic conditions. The analysis results indicate that the slip connection mechanism effectively mitigates relative displacement and damage to shear links, restricts frame damage, and enhances structural self-centering performance when combined with self-centering joints.

Cellular steel shapes offer greater section depth and strong-axis flexural stiffness than their parent hot-rolled shapes, along with web openings for duct system installation. However, their use as structural members other than beams has been constrained by a lack of design guidelines. This research employs both an analytical approach and nonlinear finite element analysis to investigate the strength of cellular steel members under combined compression and major-axis bending. In the analytical approach, the strength interaction equation for cellular steel beam-columns incorporating an initial imperfection is derived using the principle of stationary potential energy. A total of 864 FE models covering practical configurations of cellular steel shapes are analysed to assess the analytical solution and the extension of AISC360 and EC3 strength interaction equations. Effects of the parent shape, web opening configuration, member slenderness, and load eccentricity on the member strength are investigated. The results show that the proposed analytical solution accurately predicts the capacity of cellular steel members under combined compression and major-axis bending. Also, the European Code EC3 strength interaction equation that adopts the refined elastic buckling equation specifically derived for the cellular steel members can accurately predict the strength of practical cellular steel shapes. Finally, a criterion for effective utilisation of the cellular steel shapes is proposed to ensure that they exhibit greater strength than their parent shapes.

An efficient and accurate method is proposed to estimate the anti-sliding safety factor between the main cable and middle saddle of three-pylon suspension bridges satisfying the prescribed reliability levels. It is developed based on the inverse reliability method. Uncertainties in the maximum static friction coefficient, the center angle of the saddle wound with cables, the cable force at the tight side and the cable force at the loose side are incorporated in the proposed method. The unique characteristic of the proposed method is that it offers a tool for the anti-sliding safety assessment between the main cable and middle saddle of three-pylon suspension bridges when the reliability level is specified as a target to be satisfied by the designer. The efficiency and accuracy of this method concerning a three-pylon suspension bridge are studied and numerical results prove its effectiveness. Finally, the effects of some important parameters on the anti-sliding safety factor between the main cable and middle saddle of three-pylon suspension bridges are also discussed.