Simulation of post-tensioned bridge columns under reversed-cyclic loads

Thin-walled prestressed concrete structures such as bridge columns can be subjected to large magnitudes of dynamic loads. It is essential to develop a robust model to accurately predict the nonlinear behavior of these structures and thereby ensure their structural integrity under extreme loading conditions. A research project was performed to study the properties of prestressed concrete (PC) elements under shear loads using the Universal Panel Tester built at the Structural Engineering Lab of University of Houston. The test results were used to develop the softened membrane model for prestressed concrete (SMM-PC) (Wang, Constitutive relationships of prestressed concrete membrane elements, 2006). SMM-PC has been extended to the cyclic softened membrane model for prestressed concrete (CSMM-PC) by using the cyclic softened membrane model (CSSM) for reinforced concrete (Mansour and Hsu, J Struct Eng 131:44-53, 2005, J Struct Eng 131:54-65, 2005) CSMM-PC has been implemented into a finite element program to simulate the non-linear behavior of PC structures under cyclic loads. The program thus developed was named simulation of concrete structures (SCS). SMM-PC has been previously validated by tests on prestressed concrete beams under monotonic loading (Laskar et al., 12th international conference on engineering, science, construction, and operations in challenging environment, earth and space, 2010). In this paper CSMM-PC incorporated in SCS has been validated by tests on precast post-tensioned axisymmetric bridge columns under reversed cyclic loading. The analysis results of the bridge columns using SCS showed good agreement with the test results in terms of the primary backbone curves and the hysteretic loops including the energy dissipation and the strength degradation in the post-peak region. The damage and residual drift of the specimens were also closely predicted from the analysis results. Based on the accuracy of the analytical results it can be concluded that CSMM-PC implemented in SCS is an effective tool to simulate the cyclic non-linear behavior of thin-walled pre-stressed concrete structures and can be used for simulation of 3D actions of these type of structures through proper implementation