Effects of different types of corrosion on seismic performance of circular hollow section T-joints subjected to coupling load

The purpose of this paper is to investigate the effects of different types of corrosion on seismic performances of circular hollow section (CHS) T-joints subjected to in-plane cyclic load. Firstly, the validity of a numerical modeling method introducing the actual corrosion morphological characteristics was verified by comparing with experimental results. Subsequently, the influences of different corrosion characteristic parameters (corrosion types, corrosion position and corrosion level) on the hysteresis behaviors of CHS T-joints under the cyclic bending load were discussed in detail, and the analysis results indicated: 1) compared with the pitting damage, the degradation behavior of CHS T-joints with the equivalent uniform corrosion was closer to that of the CHS T-joints with the actual corrosion morphology; 2) the degradation level of cyclic bearing capacities of CHS T-joints with the general corrosion was higher than that of CHS T-joints with brace or chord corrosion under the same condition; 3) the increase in dimension of the single pit had little influence on affecting the hysteresis behavior of CHS T-joints, the bearing capacities and energy dissipation of CHS T-joints significantly decreased with the increasing distribution density of pits, even leading to the change of failure mode of CHS T-joint under cyclic bending load; 4) when the volume loss of different types of corrosion was similar, the higher the local corrosion damage, the more serious the seismic performance degradation of CHS T-joints. When the volume loss caused by different types of corrosion was transferred to the thickness loss, the ultimate capacities of corroded CHS T-joints could be calculated by applying the existing formulas. However, the calculation value was lower than the numerical results due to overestimating the adverse effects of corrosion on the axial bearing capacity of CHS T-joints.