Analysis Of Diagonal Bracing Effect Of Stairon Seismic Response Of Frame

In the traditional structure design, structure engineers design the frame structure andthe stair separately, making the stairs as the open hole, and transferring the vertical loadtransfer to the surrounding frame member. But in many earthquakes, as the importantrescue channel, staircases and related components are often destroyed seriously,completely lost its proper functions.That the stairs join frame structure, makes stairs and structure as a whole underseismic action, and increases the local stiffness of the structure, it will obviously affectnatural vibration characteristics, deformation and internal force distribution of thestructure.Based on the above background, according to the code this paper design two framemodels in SAP2000, one model that making open hole in the stairs, simulates which thestairs don’t participate in structure seismic; and another that contains stairwellscomponent model, simulates which the stairs participate in structure seismic. Then withmodal analysis and spectrum analysis of the two models in SAP2000，comparing with thethe dynamic characteristics and seismic response of the two models.The results of the study show that: the stairs increase the stiffness of overall framestructure, reduce the natural cycle of structure, and also increase base shear, which shouldnot be ignored; the stairs increase the lateral stiffness of resistance of frame structure,with the decrease of the maximum nodal displacement and the biggest displacementbetween layers, which is a kind of beneficial effects; the interaction between the stairsand the frame structure is obvious under the effects of earthquake forces, and stresschanges significantly.