This paper presents test results for four RCS subassemblies consisting of Reinforced Concrete (RC) columns and composite Steel (S) beams with reinforced concrete slab, under displacement reversals. The specimens were designed following a strong column-weak beam criterion, with the connection regions designed using a deformation-based capacity design procedure to limit joint deformations and damage. Two simple RCS joint details, consisting of either overlapping U-shaped stirrups passing through the steel beam web or steel band plates wrapping around the RC column just above and below the steel beam flanges were used to provide joint confinement. The performance of the specimens was evaluated in terms of lateral load vs. story drift response, beam and joint deformations, energy dissipation capacity, and story drift contributions from different structural components. Test results indicated satisfactory seismic performance of RCS subassemblies under large lateral displacement reversals. To evaluate the effect of joint deformations on RCS system behavior, dynamic analyses of a six-story RCS frame system under various ground motion records were conducted. In one of the three RCS moment-resisting frames analyzed, the composite joint regions were modeled as rigid joint panels. In the other two frames, the joint regions were modeled as flexible joint panels designed following a deformation-based design approach, which would limit the maximum joint shear deformations to approximately 1.2% and 0.5%. Results from inelastic dynamic analyses show that joint deformations may have a significant effect on maximum story drift, and thus joint flexibility shall not be neglected in analysis of RCS frames. In addition, different joint design philosophies may affect the inelastic deformation demand imposed on beams and columns.
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