Performance-based Seismic Design And Study On Seismic Fragility Analysis For RCS Composite Structure

Reinforced Concrete Column and Steel Beams(RCS) composite frame structure is a new structural system. It takes full use of the advantages of the reinforced concrete materials and the steel materials. Compared with the reinforced concrete or the steel frame, it adopts the concrete column and increases the stability of the structure due to the better compression performance, the large stiffness, the good fire resistance and durability of the concrete. And it adopts the profiled-steel beam and reduces the size of member section, lowers the floor height and increases the effective space of the structure, since the steel has the advantages of high strength, light quality and fast construction. At present the research on RCS composite frame structure at home and abroad is mainly concentrated in the beam-column joints and there are few researches on the seismic performance of the whole structure.Based on summarizing and analyzing the existing research materials at home and abroad, this paper establishes the seismic evaluation steps based on the performance through determining the seismic performance levels and performance goals of RCS composite frame. And a 5-storey RCS composite structure’s seismic performance is researched in this paper. The results show that the story drift under the four seismic performance levels of the RCS composite frame structure can meet the target displacement and the RCS composite frame structure has a good seismic performance.However,the results also show that this example does not meet the requirements of strong column and weak beam in the design. To solve the problem of the plastic hinge first appearing in column, this paper suggests setting dampers between the columns in the design of the seismic performance.This paper will introduce a design based on the performance of energy dissipation damper for the seismic design of the RCS composite frame structure. The single-degree-of-freedom(SDOF) system damping structure design steps will be established by drawing the damping structure’s performance curve of the SDOF system. Based on this, the key parameters of damping structure are determined and the design methods and steps of the performance-based multi-particle RCS composite frame structure are established according to the principle of proportional to the layer stiffness. The example analysis shows that according to the method proposed in this paper, RCS damping structure can achieve the goal of the performance objectives under different levels of earthquake. And compared with the traditional seismic structure, the seismic performance of the RCS has been greatly improved. The interlayer displacement angle has been reduced with the increasing degree of the levels of earthquake action. In addition, due to setting the column between the damper, the energy dissipation capacity of the pillars has also been improved and has met the requirements of strong column and weak beam in the design.This paper has respectively made a increment dynamic analysis(IDA) and a fragility analysis on the RCS composite structure with damping structure and without damping structure. And the paper compares and evaluates the seismic performance and the fragility of the two kinds of the frame structures. The results show that, for different performance levels and under the same intensity of earthquakes, the seismic performance of the damping structure is very obvious and its fragility probability is far below that of the structure without damping.