Concrete-filled Steel Plate Composite Coupling Beam And Its Application To Shear Wall Structures

To couple concrete-filled steel plate composite shear walls, and to replace thetraditional reinforced concrete coupling beams with poor ductility, a new form ofcoupling beam referred to as concrete-filled steel plate composite coupling beam wasdeveloped. A systematic and in-depth study has been carried out on the concrete-filledsteel plate composite coupling beams, and following achievements are attained:(1) Six concrete-filled steel plate composite coupling beam specimens weresubjected to cyclic loading with the same boundary conditions as those in the actualstructures. The specimens were varied in the span-to-height ratios and steel platethicknesses. Based on the test results, the failure mechanism, hysteretic characteristics,load-carrying capacities, deformation and energy dissipation capacities of theconcrete-filled steel plate composite coupling beams were investigated.(2) The modeling methods for the concrete-filled steel plate composite couplingbeams were proposed on the MSC Mentat/Marc finite element software. The compositecoupling beam specimens and eighteen additional models were analyzed by the finiteelement methods. In-depth studies were carried out on the force and deformationmechanism of the concrete-filled steel plate composite coupling beams based on the testdata and finite element results, and the development of the steel plate strains, stressdistributions, internal force distributions between the steel plates and concrete infill,force flow in the concrete infill and contribution of each deformation component to thetotal lateral displacement were investigated.(3) Basic assumptions for analyses of the shear capacities of the concrete-filledsteel plate composite coupling beams were proposed based on the results of stressanalyses. On this basis, the system of equations for calculating the shear capacities ofthe composite coupling beams was established. Through simplifying and fittinganalyses of the system of equations, the simplified design equations for the shearcapacities of the composite coupling beams were obtained. Based on the deformationanalyses, the equations for calculating the stiffness of the composite coupling beamswere established. Improved wall-beam connection details were proposed to avoidpremature fracture of the weld connection, thus improve the deformation and energy dissipation capacities of the coupled shear wall structures.(4) A sectional hysteretic model for the concrete-filled steel plate compositecoupling beam was proposed, and a nonlinear beam element model was developed forthe composite coupling beams on the MSC Mentat/Marc finite element software. Onthis basis, modeling methods for nonlinear finite element analyses of the compositecoupled shear wall structures were proposed. Pushover analyses were conducted on acomposite coupled shear wall structure to preliminarily investigate the seismic behaviorof the composite coupled shear wall structures.In conclusion, the seismic behavior and mechanics of the concrete-filled steel platecomposite coupling beam were in-depth investigated through experiments and finiteelement analyses, design methods as well as beam element model were developed,methods for evaluating the seismic performance of composite coupled shear wallstructures were also established.The dissertation was supported by the National Key Technology R&D Program ofChina (2011BAJ09B01) and National Science Fund of China (51178246).