Description
As nonlinear pushover and time-history analyses are becoming more accepted for seismic bridge design to determine displacement capacities and demands, respectively, there is a growing need to verify computer results, especially for the latter. In considering displacement and acceleration of the structure over time, for example, different computer programs might give similar maximum values but have significant differences in their calculated values of acceleration or displacement at a given time. These computer programs may also differ from results obtained through a numerical approach such as the Average Acceleration Method. The bridge design engineer has no way of deciding which program or methodology is giving the better results. In this thesis, closed-form solutions for several nonlinear time-history bridge responses for undamped free vibration are developed to validate nonlinear computer programs. A bridge with segmental precast bridge columns that have unbonded post-tensioning is displaced to any displacement ductility level and then released, resulting in nonlinear free vibration of the structure. If incremental computer results do not closely match the exact solutions presented in this thesis, the program should be investigated further and, if necessary, a different program used.
