Abstract
In this research, an improved analytical model of indirect joints in seismic retrofit method using steel braces was developed, and three-dimensional FEM analyses of direct shear test specimens of the indirect joints were carried out by using this model. The analytical results corresponded well to the test results. The authors conducted an analytical evaluation to clarify the shear transfer mechanism of the indirect joints. The results showed that if shear displacement between a steel brace and existing concrete of indirect joints in external seismic retrofit method is not large enough, there is a high probability that the anchors used in the indirect joints will be unable to exert their full shear force. They also showed that before shear slip on contact surfaces of the indirect joints occurrs, the bond resistance of the contact surfaces controls the behavior of the joints, and after that the frictional resistance of the contact surfaces and the shear resistance of the anchors control the behavior of the joints.
