Performance-Based Seismic Analysis Of Mega Steel Braced Frame-Composite Steel Plate Shear Wall Structure

A structural component parametric analysis of frame and corewall of Mega steel braced frame-composite steel plate shear wall structure has been conducted by finite element programs: ETABS and ABAQUS. Performance-based seismic analysis, Seismic fragility and collapse ratio analysis of structure are made by using the methods including Pushover analysis and Incremental Dynamic Analysis. The main research work and results are as follows:1. The structural component parametric analysis of frame and corewall of structure are made by using the methods including response spectrum analysis, elastic time-history analysis under frequent earthquake and elasto-plastic time-history analysis under rare earthquake. The results show that it can enhance structural lateral stiffness by the following measures such as setting double-story mega beams or outriggers, setting 8 single-story mega beams evenly and setting mega braces, the effect is the greatest when setting X shape mega braces. The plasticity development of steel plates will be more sufficient with slotting around the concrete plates, as long as the buckling destruction of the steel plate at slots do not take place.2. The Pushover analysis on Mega steel braced frame-composite steel plate shear wall structure is first carried out. Possible weak links in seism, the structure inelastic development and failure mode are explored under its analytic results. Then relative suggestions on structural design are proposed. Finally, the seismic performance of structure is evaluated based on the Capacity Spectrum Method(CSM). The results show that the structure failure mechanisms are similar under different lateral load pattern, the structure system has three seismic fortification lines: Composite steel plate shear wall Mega brace Mega steel frame. Pushover analysis with one lateral load pattern will overestimate or underestimate the structural seismic response. According the CSM, the result shows that the structure remains stable and erect under 8-level rare earthquake.3. Based on the method of Incremental Dynamic Analysis(IDA), seismic fragility and collapse ratio analysis are carried out on Mega steel braced frame-composite steel plate shear wall structure. The results show that Mega braces can control the displacement of structure efficiently under earthquake, reduce the collapse ratio probability of structure under severe earthquake, and composite steel plate shear wall can slow down the degradation of core wall stiffness, both of which can enhance the resisting collapse margin of structure.