Performance-Based Seismic Evaluation of Precast Concrete Frames with Hybrid Connections

The unique features of hybrid frames, which include minimum structural damage when subjected to earthquake loadings, are the result of using a combination of mild steel reinforcement and unbonded prestressing to establish connections between precast beams and precast columns. Considering the combination of two different conceptual systems, namely Non Linear Elastic (NLE) and the Tension Compression Yielding (TCY), the cyclic moment-rotation behavior of the hybrid connection can be analyzed by individually modeling the behavior of unbonded tendons and mild steel. For performance base evaluation, six hybrid frames were modeled and analyzed under earthquake input motions corresponding to three intensity levels. At each intensity level, the damage state in the buildings was quantified using the maximum transient interstory drift. The seismic performance of hybrid frames satisfied the performance limits under earthquake input motions with intensities similar to or below that of the design-level earthquake.