Cyclic Loading Tests of Composite Moment Frames Using Octagonal CFTs

Abstract

This research investigates the seismic performance of two interior beam-to-column connections with floor slabs. Concrete-filled octagonal steel tube column, H-section steel beam, and U-section steel beam were used for composite moment frames, respectively. To release the stress concentration at the column face, two design methods were proposed. First, H-section steel beam passed through the column, directly. Stopper plates were also used at the column faces to decrease the slip deformation. Second, top and bottom flanges of U-section beam were not welded to the column face. Instead, to transfer the tensile force of the beam flange, reinforcement bars passing through the column were welded to the beam flanges. The test results showed that the ductility of moment connections was sufficient in the case of through details; However, the load-carrying capacity was significantly affected by the details of beam-to-column connections.