Post-tensioning forces are modeled using two methods.  The first method converts the prestress into equivalent distributed loads that are applied directly to superstructure elements.  The second method utilizes thermal loads applied to truss elements that represent the post-tensioning cables. A GT STRUDL-based frame model is presented to implement both methods.  Total moments and stresses are comparable to those from Bridge Design System (BDS), a Caltrans’ in-house software that is currently the method of choice for Caltrans engineers. 

Numerical results will be evaluated further in a future study using experimental results extrapolated from permanent instrumentation installed on the West Street On-Ramp Overcrossing.  Pending the outcome of this study and provided proper procedure, performing prestress analysis using GT STRUDL can be a viable option for Caltrans engineers in the design of post-tensioned bridges.

The required GT STRUDL input data and commands will be discussed during the presentation.