Seismic damage assessment of four⁃limb CFST latticed columns based on a nonlinear dual-parameter damage model

To evaluate the seismic damage of four-limb concrete-filled steel tubular (CFST) latticed columns (4-L CFST LCs) in a mega composite frame structure system, four specimens were tested under horizontal low-cycle repeated loading (HLCRL), and the failure modes and component damage characteristics of 4-L CFST LCs were obtained and analyzed. Based on the experimental results, the energy and displacement terms and the energy and displacement coefficients were combined and modified respectively; and a dual-parameter nonlinear combined damage model applicable to 4-L CFST LCs was established based on the traditional dual-parameter linear combined damage model. The experimental results show that the modified model is more in line with the actual situation of component failure and can more accurately reflect the damage index of 4-L CFST LCs in each displacement stage, providing a basis for the seismic damage analysis of 4-L CFST LCs and its structure in a mega composite structure system.