The Seismic Behaviors Of Concrete Filled Steel Tubular Laced Columns-composite Box Girder Joint

Mega composite structure system has adapting to the requirements of the development of modern architecture over the recent years, which has the unique advantages different from other mega structural system. The design and calculation of composite joint plays a crucial role in the mega composite structure system’s seismic behavior, but the composite joint’s experimental study and theoretical research lagged behind the engineering practice, especially in the research field of mega composite structure’s joint. Therefore, the joint of concrete filled steel tubular laced columns-composite box girder in the mega composite structure system, which are studied by experimental and theoretical analysis in this paper. The specific research contents are as follows:(1) Three different connection forms of concrete filled steel tubular laced columns-composite box girder joint are proposed and designed in the paper, those different connection forms are single way brace, cross sway brace and diaphragm plate. The joints are tested by low cyclic loading. The load-displacement hysteretic curves are obtained by the experiment, and the joint seismic behavior indexes such as skeleton curve, bearing capacity, ductility, stiffness degradation, strength degradation and energy dissipation capacity are analyzed in detail with considering of the influence of the different connection forms.(2) With using finite element analysis software ABAQUS and Selecting proper material constitutive relation, the finite element models of concrete filled steel tubular laced columns-composite box girder joint are established, and the whole load-displacement hysteretic curves which are analyzed by software are compared with the test results. The result of software verify the correctness of the finite element models, the joint’s connection choice and size have done some corresponding optimization analysis.(3) In the light of the joint’s different connection forms, the shear mechanism and failure mode of the concrete filled steel tubular laced columns-composite box girder joint are investigated. And the method of calculating its shear resistance is deduced basing on related theory. According to the shear resistance formula, there kinds of joint shear resistance in the experiment are calculated and checked, also the reliability of the shear resistance formula are tested.