Seismic behavior of RCS beam-column subassemblies and frame systems designed following a joint deformation-based capacity design approach.

摘要

Several studies have been conducted during the past twenty years in the U.S. and Japan to investigate the behavior of composite joints between reinforced concrete (RC) columns and Steel (S) beams. To evaluate the use of RCS systems in regions of high seismicity, the seismic behavior of RCS beam-column subassemblies designed for controlled joint deformations and following a strong column/weak beam criteria needs to be further studied. The overall seismic response of RCS systems also needs to be evaluated analytically to evaluate their performance during earthquakes.; This research program investigated the behavior of two interior and two exterior RCS beam-column-slab subassemblies under reversed cyclic loading. The test specimens were designed following a strong column/weak beam criteria and a deformation-based joint design model that was developed in a previous study at the University of Michigan. Two types of RCS joint details, one with overlapping U-shaped hoops passing through the steel web panel and one with steel band plates wrapping around the column above and below the steel beam, were used in the test specimens. In general, the RCS subassemblies exhibited stable responses and excellent energy dissipation capacity, and both joint details provided effective shear and bearing resistance. The deformation-based joint design model proved to be effective in limiting joint deformations and controlled joint damage to moderate level.; The effect of joint deformations on the seismic response of RCS systems was studied through inelastic dynamic time-history analyses of three RCS frames under selected ground motion records. One of the frames was modeled with rigid joint panels and the other two frames had flexible joint panels capable of simulating inelastic joint behavior. The joint panels in these two frames were designed following a strength-based and a deformation-based design philosophy. Analytical results indicated that the maximum story drifts in RCS frames with rigid joint panels were significantly lower than those in frames that included joint deformations. The deformation-based joint design philosophy effectively limited joint deformations, but did not significantly affect the maximum story drift under the selected ground motion records, compared to the RCS frames that used strength-based joint design.