Experimental study on seismic behavior of steel-reinforced concrete square column and steel beam joint with bolted end-plate.

In order to investigate the seismic behavior of steel beam to steel-reinforced concrete filled square steel tubular column connections, five specimens were tested by quasi-static tests. The influences of end-plate thickness, bolt diameter, concrete strength and axial compression ratio on the load-carrying capacity, moment-rotation curve, energy dissipation capacity, load degradation, rigidity degradation, ductility and ultimate failure modes of end-plate connections were analyzed. The experimental results show that these new type of composite connections belong to the category of semi-rigid connections, and the initial rotational stiffness of connections increase with end-plate thickness and bolt diameter, but the utmost rotational capacity of connections decrease with end-plate thickness. The connection shows excellent behavior in terms of ductility and energy dissipation when the strength of connection is controlled by end-plate or steel beam. The load degradation coefficients of all specimens are between 0. 8 and 1.0, varying within a narrow range. Compared with load degradation, the rigidity of specimens degrades seriously. Moreover, the high strength bolt should avoid brittle failure in the design procedure. [ABSTRACT FROM AUTHOR]