Buckling Behaviour of Q355 Angles with Simulated Local Damages at Bolted Connections

Transmission towers in service are highly susceptible to corrosion caused by environmental conditions. It is crucial to assess the residual load capacity of corroded angles in transmission towers. In this study, corrosion at the connection of angels was simulated by local damage using a mechanical cutting method, and compression tests and numerical simulations were performed to investigate the load capacity of corroded angles. A total of 24 angles were designed and tested in the experiments, and the parameters considered included the location and thickness of damage and slenderness. The local damage was designed on the loaded or non-loaded legs, with slendernesses of 80 and 140, and a thickness of damage of 1 mm and 2 mm. The residual load capacity, failure modes, and strain of the angles were analysed based on experimental results. Furthermore, corrosion was simulated by reducing the local thickness of angles using ABAQUS. The accuracy of numerical models was verified after comparing the numerical results with experimental data. Based on the verified model, parameter analysis was conducted, in which the slendernesses was extended to 100 and 120, and the local damage thickness was also set to be 0.5 mm and 1.5 mm to quantitatively study the influence on the residual load capacity. The tests results showed that with the damage depth at the ends of the angle increased, and the load capacity of the angle decreased by up to 6.7%. Finally, a design equation for calculating the residual load capacity of corroded angles was proposed using the numerical results. By comparing the design equation, experimental results, and load capacity calculated per existing standards, it was found that the load-bearing capacity of corroded angles can be accurately predicted by the equation.