Analysis Of Seismic Collapse Mechanism For Beichuan Traffic Bureau Frame Structure In Wenchuan Earthquake

The collapse of reinforced concrete frame structure in earthquake caused a large number of casualties and economic losses.It is a great of practical significance to study the collapse mechanism of the frame structure,which provides important reference for seismic structure design,seismic retrofit and earthquake relief work.In this paper,the ABAQUS finite element software is used to analyze the reinforced concrete frame structure of the Beichuan Traffic Bureau,which had completely collapsed in Wenchuan earthquake.The main contents and conclusions are summarized as follows:1.The earthquake damage of Beichuan Traffic Bureau frame structure was investigated.The main seismic damage of the building was as follows: the bottom two layers of the structure collapsed;a large number of plastic hinges appeared in the upper four floors and the upper four floors had seriously tilted;the infilling walls were cracked in large areas,and some of them were collapsed;and the stairs were severely damaged.2.The Beichuan Traffic Bureau frame structure is analyzed by using dynamic time-history analysis.And the results of dynamic analysis were discussed.Large numbers of plastic hinges were formed in the damaged structure.The failure modes were the two bottom floors' collapses.3.The anti-seismic collapse capability was analyzed and evaluated basing on the incremental dynamic analysis by using 22 time history records accordance with the ATC-63 report recommended and a time history record in Wenchuan earthquake.The Collapse Margin Ratio equals to 2.44.4.The effect of additional wing wall on the seismic performance of the frame structure was studied through numerical simulation.The analysis results show that the addition of wing walls can increase the lateral stiffness of the structure,reduce the displacement response of the structure under earthquake,and achieve the purpose of multi-channel anti-seismic defense.