Analysis Research On Impact Of Stair Position On Seismic Response Of Frame Structure

In the previous earthquakes, serious damage always happened in the stairwells of frame and masonry structures. Usually, stairs were damaged before the main structure, make emergency use impossible. However, the study of seismic design of the stairs was very limited allover the world. Urgently, many problems need to be studied and solved. Since the stairs of frame structures were damaged most seriously in the earthquake, and stair itself has considerable rigidity, the position of stairs is bound to affect the whole structure. Therefore, on the basis of summing up the stairwell earthquake damage, this paper focuses on the effect of stair position to the seismic response of frame structure.The research work in this paper mainly involves:(1) Sum up the forms of stair damage in the previous earthquake. List the research results of stairs seismic problems;(2) Establish six multi-storey frame structure models in SAP2000, in those models, stairs are located in different position;(3) Collate the cycle, mode shapes, forces and other information on the basis of modal analysis. It’s found that the location of the stair causes a great impact on the torsional rigidity of structure, the internal force of the structure also changes significantly as the location of the stairs change;(4) A new nonlinear model is used for Pushover analysis, comparison of the failure mechanism of the six models is made. Analysis shows that in order to avoid plastic structural damage, the position of staircase should follow the principle of increasing torsional rigidity of structure;(5)The effect of stair position to the seismic response of frame structure is summarized, suggestions are proposed to judge the best position of stairs, and several new methods of seismic design of the staircases are given.This paper has a certain reference value for design of frame structure with staircases.