The Research On Performance-based Seismic Evaluation And Seismic Measures Of Frame-stair System

The stairs structure holds the key position in the vertical transportation of multi-storey buildings and high-rise buildings,and also should become safety island in favor of people’s evacuation when the earthquake happens. Lots of disaster investigations show that some staircases in different buildings were damaged severely especially in frame structure buildings, and it damaged earlier and more severely than the other parts.The yielding process of frame structure and staircase in the earthquake can be understood by the static elasto-plastic analysis of typical systems, and provide the evidence for seismic design and ductility measures. As a practical method of static elasto-plastic analysis, the pushover analysis can analyze the ductility of the structure’s anti-seismic performance accurately and becomes more and more applied in the seismic design. In this paper, the frame-stair system’s yielding process can be showed and the system’s anti-seismic performance can be learned by the pushover analysis method.Firstly, the work mechanism of the staircase was introduced, the current research of the union work of frame structure and the staircase structure was proposed. Then, the seismic performance design of structure was introduced. The applied background and basic theory of pushover analysis were introduced, the realization of pushover analysis in SAP2000was also introduced.Secondly, Using the finite element software SAP2000V15, a typical frame-stair system and a frame system without stairs were established. The differences of the two modal’s dynamic characteristics were compared and the effect of the stairs on the rigidity of the structure was analyzed. Through the response spectrum analysis, the effect of the stairs on the beam moment and the column’s axial force were analyzed. The stress state of the stair slabs was also understood. As a result, different pushover curves were obtained under typical horizontal load patterns. The plastic hinge’s sequence of appearance could appear. Then, the yielding mechanism of the two modals could be obtained by the pushover analysis, the difference and similarity were compared. The different performance points of the two modals at different earthquake degrees could be obtained,the system’s anti-seismic ability of the system could be evaluated by comparing the plastic hinge’s different situation of the beams, the columns and the stair slabs.Lastly, according to the conclusions of push-over analysis, a kind of reasonable joint of stairs structure in frame-stairs system called Horizontal Slip-support stairs was put forward. In addition,a series of concrete measures to carry out this mentality was put forward, including the boss measure, to seam and softly brittle block and endeavour to set sliding bearing surface in the bottom of the stairs’s slabs,etc.