The Effect Of The Stairs On The Seismic Performance Of The Different Structures

In recent years,earthquake that takes place frequently makes the community’s focus on the seismic performance of structures,structure capacity for disaster prevention and evacuation capacity.The stairs are not only a tool contacting the floors in peacetime,but also an important channel of evacuation during the disaster.From the Wenchuan earthquake and the Yushu earthquake,the researchers find the case that some concrete or masonry structures are basic integrity,while the stairs is serious damage.At the result,the stairs can not perform what it is given,and hinder the successful escape of internal staff and external rescue.Therefore,it is essential to carry out the effect of the stairs on the seismic performance of the different structures.The paper makes the following works mainly.(1)Modeling frame structure,frame shear wall structure,shear wall structure by finite element analysis software and making mode shape and response spectrum analysis for all models.Then researching the effect of stairs on dynamic behavior,cycle,displacement of structures and showing the effect do exist.In addition the existence of stairs will have a most impact on frame structure,followed by frame shear wall structures,and have little impact on shear wall structure.(2)Analyzing the internal forces of the members making up stairs and showing gangboard,landing beam and ladder post not only carry vertical loads,but is also affected by horizontal loads.Hence both of them should be considered in the design of stairs.(3)Analyzing the internal forces of the structure member making up stairwell and showing the existence of stairs will have a more impact on the internal forces of the frame structure and frame shear wall structure member making up stairwell structure compared to shear wall structure.The point should be valued in the design.(4)Analyzing the internal forces of the structure member around stairwell and showing the existence of stairs will have a most impact on the internal forces of the frame structure member around the stairwell compared to frame shear wall structure and shear wall structure.