Experimental research on stiffness of semi-rigid connection in beam-column and effect on steel frame ductility

Semi-rigid connection is one of the approaches to improve the ductility in frame structure. It will be absorbed earthquake energy by the deformation of angle steel and bolts. The new type of semi-rigid connection with web opening has been proposal. Four specimens under cyclic load were tested. The relationship between the moment of beam end, the bearing capacity and the rotation can be described by means of a moment-rotation curve, and hysteretic behavior is discussed. The result indicates that thickness of angle steel and pre-stress of bolts are the keys that ensure the ductility of semi-rigid connection. Moreover, the web opening influenced on hysteretic behavior of connection. The effect of steel frame ductility due to different stiffness of connection has been discussed in this paper. The finite element method was also used to analyze frames model including the test data of semi-rigid connection. Analysis results show that the new type connection with web opening in reasonable position can improve the ductility for steel frame.