| Many experiments have been conducted in the last ten years on composite joints between steel beams and reinforced concrete columns in both the US and Japan. This is aimed at realizing more efficient structures from the standpoints of structural performance, construction cost, and space planning by efficient combination of concrete and steel materials. However, due to the complexity of the internal force transfer mechanisms, full understanding of the joint behavior has not been achieved. In particular, concerns related to seismic design have been cited as one of the important issues to be further studied.; This research investigates the behavior of composite beam-column joints, with emphasis on behavior under reverse cyclic loading. Attention is paid to the strength, deformation, and seismic resistance of the joint. Nineteen large scale interior beam-column subassemblages are tested under reverse cyclic loading, considering various factors such as subassemblage failure modes, joint failure modes, joint details, axial column load, and concrete strength. In addition to the subassemblage tests, smaller scale component tests are conducted to study the concrete bearing strength inside the composite joints. Moreover, over forty experimental results reported by other researchers in both the US and Japan are reviewed to provide additional background for developing design models and guidelines.; Using behavioral information from the experiments, force transfer mechanisms in the joint are described and design models and equations are proposed. Analytical models for the joint deformation are also developed. The seismic resistance of the joint is discussed using damage indexes and design implications for the seismic design of the joint are provided. Overall, the joints demonstrate reliable strength under both monotonic and cyclic loading. In addition, the joint deformations and seismic resistant performance are comparable to those of seismically designed steel structures and reinforced concrete structures. |
