Research Of Plate Stairs Collapse Resistance Impact On The Frame Structure

The stairwells are often destroyed before the main structure under seismic action.This article studies the impact on the plate stairs to the seismic collapse resistance of frame structure. It mainly designs a computational model of three groups of RC frame model with stairs and without stairs of14bays,10bays and7bays, and the stairs of different locations etc, which respectively research stairs effects on different bay structure and different location. Using MSC.MARC finite element software, and ATC-63proposed incremental time-history analysis (IDA) and seismic wave library, this article simulates the entire process of the structure collapse under seismic action, and also be quantitative evaluation of the seismic collapse resistance for each structure in the rare earthquake, improve once great earthquake and the mega earthquake, mega earthquake by adopting the average spectral acceleration Sa(T1)50%collapse, CMR and collapse rate. Finally, evaluation of the seismic collapse resistance between the two improvement designs of the stairwells, draw the following conclusions:(1) The structure design without considering the role of the stairs can not reflect the effect of the overall structure collapse resistance and the partial damage characteristics of stair under seismic action, while now the design procedure is more conservative.(2) After considering the effect of the structure design, the greater proportion the stiffness of the stairs is, the more improvements of the seismic collapse resistance are, while the more reduction the stairwells partial collapse resistance capabilities is. As the multi-bay structure, position changes as the stairwells symmetrical arrangement has little impact on the seismic collapse resistance of the overall structure; stairwells layout in the vicinity of the structure center, stairwell partial collapse rate of13.33%,77%higher than pure framework.(3) Cases show that the stairs first collapsed under seismic action, which is the same as the actual and then the frame column becomes the weak parts of the structure.(4) If separating the stairs from the main structure, the design improved becomes dual staircase column, it can effectively reduce the adverse effect on the main structure to avoid the stair component be damaged first.