This study examines the dynamic response characteristics and impact factor (IF) of a multi-rib, special-shaped tied-arch bridge under heavy truck loads. Field traffic tests were performed, and finite element models were validated to analyze the bridge's dynamic response to moving vehicles, obstacle crossings, and emergency braking. The results show no significant correlation between the speed of moving vehicles and the bridge's IF. However, under obstacle-crossing and braking conditions, the bridge's IF increased with speed, reaching 4.2 times and 3.1 times the standard design value, respectively. Additionally, as deck roughness worsens, the IF increases, with the arch ribs being most sensitive to these changes. The study also found that an increase in the number of vehicles, when spaced appropriately, can significantly reduce the bridge's IF. The lateral position of the vehicle has a minimal effect on the IF of the main girder and arch ribs, but a notable impact on the IF of the hangers. Copyright (c) 2026 by The Hong Kong Institute of Steel Construction. All rights reserved.
Combined bolted angle beam to column joint had the advantages of high bearing capacity and considerable deformation capacity, which are desirable characteristics for semi-rigid connections considered in earthquake-resistant frame structures. This paper focuses on the fundamental bending performance and design of a novel connection type that using through-core bolts to connect the angle and hollow square section column (HSSC). The bending performance was simulated using the verified finite element model (FEM) by means of monotonic loading, and the parametric analysis included angle flange thickness, angle steel strength, bolt vertical distance, stiffening rib position, thickness, shape, and number and double web angles. The results showed that angle flange thickness, steel strength, and bolt vertical distance had significant impact on bearing capacity of joints and the parameter of stiffening rib had little effect on initial stiffness. For unstiffened angle joints, the pattern of yield line was three straight lines located at the root of angle flange, angle web, and throughout bolt holes, respectively. It can be changed to two circular arc curves by setting stiffening ribs, which increased the bearing capacity of joints obviously. The web angle only formed yield line in tension zone and the pattern was the same as top angle. Three types of design method were proposed for unstiffened angle, stiffened angle, and web angle joints, respectively, by referring to the yield line theory given in Eurocode 3 and P398. Compared with results obtained from FEM, the calculated values were highly consistent with, demonstrating the reliability of the formula.
Friction-type high-strength bolted connections have gradually become popular in steel structure buildings due to their inherent advantages, but their shear resistance capacity still needs to be improved. To better enhance the anti-slip performance of ordinary steel structure connections, this paper proposes an innovative anti-slip connection concept that involves embedding specific particles into the surface of ordinary steel. This method enhances the shear resistance of the connection by increasing the friction coefficient of the contact surfaces, with significant effectiveness. Appropriate particle materials and shapes were selected via theoretical analysis. The concept's effectiveness and feasibility were verified via two static test stages: particle embedding tests on steel plates and anti-slip tests of bolted connections under pre-tension. The study reveals the influence laws of factors such as particle diameter, arrangement pattern, distance from the hole wall, and the magnitude of bolt pre-tension. Results of the particle embedding tests indicate that for 6mm steel plates, when the particle diameter is less than 3.5mm, the embedding load increases approximately proportionally with the number of particles. The anti-slip test indicates that as the diameter and number of embedded particles increase, the connection slip coefficient improves significantly. Embedding 4 particles with a 3mm diameter results in a connection anti-slip coefficient of 2.8. The new particle-embedded connection outperforms friction-type high-strength bolted connections in maintaining stable anti-slip loads, highlighting its potential for engineering applications. Copyright (c) 2026 by The Hong Kong Institute of Steel Construction. All rights reserved.
Welding technology offers high efficiency and flexibility in the bridge construction. However, weld-included defects are inevitable and significantly reduce the fatigue performance of welded joints. Porosity is one of the most common welding defects and has a considerable influence on fatigue performance. In this study, both fatigue tests and numerical simulation are used to investigate the effect of porosity defects. Test specimens of butt-welded and cruciform-welded joints were designed, with 48 specimens divided into two groups, including 24 specimens with porosity defects and 24 control specimens without pores. The results indicate that the fatigue strength of butt-welded joints and cruciform-welded joints without porosity defects with 2 million cycles was 142.0 MPa and 92.3 MPa, respectively. When the pore depth and diameter were both 2.0 mm, the fatigue strengths of butt-welded joints and cruciform-welded joints with porosity defects decreased by 27.4% and 7.3%, respectively. Numerical simulation results showed that porosity significantly increased the stress concentration factor (SCF) of the welded joints. The diameter, position, and depth of porosity had clear effects on SCF. An increase in the pore diameter significantly elevated SCF, although the rate of increase diminished when the diameter exceeded 1.6 mm; the SCF decreased when the pore was located farther from the weld toe, with cruciform joints being more sensitive to pore position; surface pores caused significantly higher SCF than internal pores, and the SCF was higher when pore depth was closer to the weld surface. Copyright (c) 2026 by The Hong Kong Institute of Steel Construction. All rights reserved.
A novel generation of hybrid stainless steel girders, featuring high-strength stainless steel flanges and conventional stainless steel webs, has been developed and is increasingly used in marine structures. This hybrid configuration provides enhanced flexural capacity while simultaneously reducing material consumption and structural weight compared with conventional homogeneous girders. However, no established design rules currently exist for such hybrid steel girders. As a result, the resistance and design of such hybrid stainless steel girders under localised forces should be carefully evaluated. This study aims to fill the gap by expanding on previous experimental work and proposing simplified design methods for predicting the resistance of hybrid stainless steel girders under localised forces using numerical methods. A robust finite element (FE) model, previously developed and validated by the authors, was utilized to conduct an extensive parametric study, generating a total of 1248 FE results. This study focused on key parameters, including the bearing width ratio, web aspect ratio, web slenderness, and local geometric imperfection. The numerical results were analysed to assess the reliability of existing design guidelines, namely GB 50017-2017, EN 1993-1-5, and ANSI/AISC 360-22. The analysis revealed that the predicted values from GB 50017conservative estimates, with average deviations of 44.7% and 19.8%, respectively. To address this issue, new design proposals were formulated, incorporating a modified coefficient within the framework of existing design rules.
