Cyclic Loading Tests of Novel Precast Bridge Columns with Off-Site Post-Tensioned Tendons and On-Site Socket Connection: Fid-Bau Portal

Cyclic Loading Tests of Novel Precast Bridge Columns with Off-Site Post-Tensioned Tendons and On-Site Socket Connection

Jia, Junfeng / Bian, Jiachen / Xu, Kun / Qiu, Canxing / Du, Xiuli / Guo, He / Pang, Wei

This paper proposes a new post-tensioned (PT) precast bridge column (PBC) with a socket connection. PT steel tendons and unbonded steel rebars provide self-centering capability and energy-dissipating capacity, respectively. Because the PT tendons are off-site anchored, they can effectively shorten the on-site working time and improve the safety and tolerance of construction. After describing the configuration and mechanism of the PBC, the analytical equations governing its cyclic behavior are derived. In the quasi-static cyclic loading test results, five PBC specimens and one cast-in-place (CIP) bridge column are designed, based on the criteria that their lateral “yield” strengths are identical, i.e. the concept of equivalent lateral force design. The results show that the PBC specimens realized the targeted lateral strength and exhibited self-centering damping behavior. Compared with the test data, the errors of the “yield” and ultimate strengths predicted by the analytical equations were −9.3% and 8.0%, respectively. The PBC specimens remained nearly intact throughout the tests, although minor cracks were detected in the concrete. In contrast, spalling of concrete and buckling of rebars were observed in the CIP specimen. The comparisons between the PBC specimens indicated that the novel bridge column could maintain self-centering capability and achieve the largest damping capacity when the lateral force-resisting contribution ratio of energy-dissipating steel rebars is 35%, the PT tendons are prestressed to 35% of ultimate stress with a reinforcement ratio of 0.35%, and the embedded depth is 0.7 times the width of the column.