Nonlinear analysis of hybrid sliding-rocking post-tensioned segmental bridges

In this paper, two numerical modeling approaches for nonlinear analysis of hybrid sliding-rocking (HSR) post-tensioned segmental bridges are explored. The HSR bridges incorporate: (i) substructure columns with slip-dominant joints and straight PT tendons (termed HSR-SD columns), and (ii) superstructure girders with rocking-dominant joints and curved PT tendons (termed HSR-RD girders). In the first approach, a 3-D model of a precast concrete HSR-SD pier column is generated using the ABAQUS general purpose finite element analysis software. This model is used to simulate the experimental response of an HSR-SD column specimen subjected to quasi-static lateral cyclic loading in the Structural Engineering and Earthquake Simulation Laboratory (SEESL) at the University at Buffalo (UB). The numerical model was capable of capturing the sliding and rocking at the joints, and the numerical solution was in good agreement with the experimental data. These analyses required vast computational resources and time, and, eventually, halted due to numerical instabilities that resulted from strain localization at the concrete solid elements. In the second approach, a model of a large-scale HSR bridge specimen tested in SEESL is generated using only two-node elements available in commonly used structural analysis software; in this case SAP2000. The model provided better results when the response was dominated by joint rocking rather than sliding. Moreover, numerical instabilities and analysis failures were observed in the presence of intense joint sliding.