Analysis Of The Interaction Between Different Stair Structures And Frame Under Horizontal Earthquake Action

Stairs is vertical traffic aisle of the building, with the function of access and evacuation, is an important part of building construction. According to building function, the plane position and geometry size of the stairs is determined by the architectural design, which meet the relevant specifications of the building. The structure style of the staircase depends on the structural design. In Wenchuan earthquake, the frame structure of the stairs were severely damaged, which caused widespread concern. Many interior experts and scholars published a series of articles on this issue. And there is a general consensus that stairs have a great influence on the performance of the overall structure of the work, it can not be ignored in the actual structure of the design. The new code for seismic design of building clearly stated,"The influence of the stairs member should be considered into the calculation."In the general framework structure, the staircase structure commonly adopts the straight staircase and folded-plate staircase. In actual operation, they both can be used if the span is not too big. Due to the different forms of the staircase structure, the setting of stairwell member also have an different effect on the stiffness of the frame structure, the stairwell adjacent frame beams, the frame column and the corner posts. Base on specific examples of projects in Ningxia, adopt SAP2000finite element software, set up five models, use modal response spectrum analysis, make a comparison among each model cycle, the modal mass participation coefficient, floor displacement layer drift angle and basal shear to find the existent differences. By analyzing the stairwell adjacent frame beam, the frame columns and the stairs components of the internal forces of the five models and summarizing each model’s impact on the surrounding frame member, this paper put forward some views on the choice of staircase structure form, the construction of processing and the seismic design. The research hopes to provide a reference for future structural design.