Performance Of Precast Connections On A Moment Resisting Frame Under Cyclic Loading

Precast concrete structural systems have been proved to be a cost-efficient alternative to cast in-place reinforced concrete and structural steel systems. Advantages of these structural systems are high speed of construction, improved quality control, reduced total construction cost, versatility, flexibility in the architectural form of the members, and efficient and sustainable material use. Despite many advantages of precast concrete, it is not widely used in the United States, especially in areas of high seismic risk due to lack of knowledge about their performance. Several precast parking structures showed poor performance in the 1994 Northridge earthquake due to incorrect detailing of the connections. This study aims to investigate the behavior and develop detailing of hybrid beam-column connections to be used in precast moment resisting frames. Three-dimensional (3D) nonlinear finite element models were built to compare and validate the behavior of precast hybrid beam-column connections subjected to cyclic loading against experimental work. The models include detailed analysis and investigation of the concrete and steel behavior up to failure. Good comparison between the FE results and previously tested members has been achieved which leads to studying and investigating multiple parameters that affect the performance of such connections: reinforcement amount of beam elements, geometry of steel connection components, amount of bolt pretension, and method of anchoring the connection components in beam elements. Prying action in steel angles, a function of strength and stiffness of the connection elements under tension, was also investigated as a failure mode of such connections.