Seismic response of R/C frames with friction-composite moment connections

The beam-to-column connections are the most important components in the mechanism developed by framed structures to absorb and dissipate the energy imposed by an earthquake. Unfortunately, although the ductile connection is capable of undertaking large deformations, it does not have the capability to return to its initial strength and rigidity. In addition, its construction is very difficult due to the large amount of reinforcement needed for confinement. The present design philosophy proposes that the structure must be provided with the needed ductility to resist the earthquake in the inelastic range. As a result of this study, a new beam-to-column connection is proposed in which the moment capacity comes from a frictional mechanism. The possibility of implementing this steel connection in reinforced concrete framed buildings was studied through analytical and experimental programs. In the analytical part, a computer program was developed to perform nonlinear dynamic analysis of the frames with the friction type connections. The results were compared with traditional reinforced concrete frames, considering parameters as the total energy imposed by the earthquake, the maximum floor lateral displacement, and the base shear. In the experimental part, the behavior of steel friction connections and the necessary detail to transfer adequately the strains in a composite element were studied. It was found that is possible to build friction composite moment connections and their capacity can be predicted accurately. In the analytical part it was found that frames with these connections have improvements in comparison with the conventional ones.