Hysteretic Behavior And Design Criterion Of Composite Steel Frame-Reinforced Concrete Infill Wall Structural System With PR Connections

As a new type of brace resistant steel frame, the composite steel frame-reinforced concrete infill wall (SRCW) structural system, in which the steel and concrete components work integrally through mechanical connectors, increases the lateral stiffness of traditional moment resistant steel frame, so that provides the opportunity to use partially-restrained (PR) connections instead of more expensive fully-restrained connections. The SRCW structural system has favorable seismic resistant performance in the regions subjected to earthquakes. Because the international and domestic research of SRCW structural system is still in the primary stage, the cognition of force distribution and bearing performance was rather inadequate. Therefore making study on the hysteretic behavior of the SRCW structural system under cyclic load and introducing aseismatic design recommendations are significant for theory and practice.In order to realize hysteretic behavior of the SRCW structural system factually and offer foundations for the corresponding analyses using finite element method, a two-story, one bay specimen was tested under cyclic load, after that the general behavior, local response and force distribution of the specimen were evaluated. The results show that the system has ample lateral bearing capacity and high safety factor. At the design load level, the RC infill undertakes 80%~90% of the lateral load;the steel frame undertakes 80%~100% of the overturning moment.On the basis of the experimental results, this paper applies nonlinear finite element method to simulate the system at the first time, in which, the six main influential factors, such as rotational stiffness of the connections, numbers of the headed studs, reinforcement ratios, compressive strength of the concrete, width of the infill wall and vertical loads from upper stories are taking intoconsideration. After synthesizing the results of experiment and FEM research, the aseismatic design recommendations are brought forward.The application of the SRCW structural system with PR connections is very wide. This study can be useful for revising code, guiding engineering design and making bases for future research.