Influence Of Stairs On Seismic Performance Of Frame Structure

At present, stair components are not included in design of frame structure. Instead, the load generated by stair components is uploaded on peripheral components. However, as the main vertical passageway of building structure, stairs are essential traffic aisle in saving lives from disaster. In the meanwhile, survey data of all previous earthquake disasters shows that there is a large proportion that the damage degree of staircase is higher than main structure of building, which bereaves the critical role playing by staircase during disaster.Finite element analysis software SAP2000was employed to establish the special finite element model with different influencing factors considered, and the stairs structure impact on overall deformation of structure and loaded property of construction members under different elements were discussed in this thesis. The main contents are shown as follows:Stairs impact on seismic performance of frame structure was analyzed in this paper. By SAP2000, we modeled and analyzed the impact of different number and location of stair structures on ferroconcrete frame structure, and the impact of staircase on different layers, spans and story of ferroconcrete frame structure.5different frame structure models including A (4layers,7spans), B (4inhomogeneous-height layers and7spans), C (4layers,9spans), D (6layers,9spans), E (6layers,9spans) were established by SAP2000. Study the dynamic characteristics of each model, as well as the earthquake, we compared the influence of stairs on structure period, story drift and connected columns between different staircases.5structure models with different locations and numbers of stairs within the same framework were established by SAP2000:model A-l (located at side), A-2(located at the second span from side), A-3(asymmetric arrangement), A-4(located in the center), A-5(Single staircase located in the center). Comparative study the effect of stairs with different locations and number on structure.Base on SAP2000, time-procedure analysis of models under3different seismic waves (EL wave, CPC wave and a simulated wave) was performed and compared with results of response spectrum analysis in order to evaluate the stairs impact on maximum displacement between different stories and story shear force. Meanwhile, top layer’s displacement time-histories curve was output for each model to describe to layer displacement change with time change under observed seismic waves.