Seismic Fragility Analysis of RC Diaojiao Frame Structure in Luding Red Bed Area Based on IDA

The reinforced concrete (RC) Diaojiao frame structure is a widely used building form in the Luding red bed area. A large area of damage occurred in the Luding earthquake in 2022. It is very important to carry out seismic fragility research for damage evaluation and post-earthquake emergency management. Based on the incremental dynamic analysis (IDA), this paper explores the dynamic response law of the structure: the structural damage is distributed in Floor 1 > Floor 2 > Floor 3, and the damage of the C1_1 component is the most serious. Through the quantitative analysis of the structural damage matrix, the probability of structural damage under frequent earthquakes of 7 degrees and 8 degrees can be ignored. The probability of severe damage (SD) of Floor 1, Floor 2, Floor 3 and the building under maximum considered earthquakes of 9 degrees is 58.25%, 53.03%, 2.71% and 36.79%, respectively. In this paper, PGA is used as an index to divide the damage state into four categories: elastic state, elastic-plastic state, plastic state and large deformation state. Based on the actual earthquake PGA, the structural damage can be determined quickly and accurately, which provides scientific support for the formulation of emergency measures.