Seismic Performance Assessment of Frame Pier with Double-Stage Yielding Connection

Beam–column connections are vulnerable parts of a frame pier under lateral earthquake. This paper proposes a novel double-stage yielding beam–column connection (DYC) for seismic damage control. The main feature is the use of two kinked steel plates (KSP) in the upper and lower edges of the DYC to tolerate the deformation induced by the beam–column rotation. Hence, the major RC column and beams could be protected from plasticity development. Five KSP samples and one DYC specimen were designed and tested. The experimental results indicated that the DYC had a secondary yielding mechanism due to the straightening of the kinked segment. Benefitting from the deformation redistribution, the DYC specimen experienced slighter plasticity in the major RC components than did the traditional RC connection. Based on the tests, a multiscale numerical model was developed, which yielded good agreement with the test results. Dynamic analysis of the benchmark bridge was performed to evaluate the seismic performance. The overall response of the whole bridge and local behavior of the connection were compared. The influence of the springing height and angle is discussed. To effectively control the seismic damage under earthquakes of varying intensities, the design method of DYC is proposed.