| This dissertation describes research on the seismic design and performance of precast concrete segmental bridge columns reinforced longitudinally with internal unbonded prestressing tendons. The use of precast segmental construction for bridges has increased in the past couple of decades, but not in regions of high seismicity due to unknowns regarding the behavior of this bridge type during earthquakes. The aim of this research is to establish the behavior of precast concrete columns under lateral seismic loading and to formulate a design procedure and guidelines that ensure good seismic performance.; The lateral strength and deformation characteristics of a precast segmental column are first developed analytically and then verified through experimental testing of large-scale precast concrete columns. Then, based on the experimental results and the analytical model, a design procedure that utilizes the direct displacement-based design method [2, 9, 10] and design charts, is developed. A design study that compares the required design quantities and expected seismic performance of the precast column system with that for conventional reinforced concrete columns is presented. Inelastic dynamic time-history analysis is performed for the designs in order to verify the accuracy of the design procedure.; It is shown that the response of the precast column to seismic loading is reasonably well predicted by the analytical model and ductile behavior of the precast column is achieved with less damage as compared to conventional reinforced concrete columns. It is also shown that if precast and conventional reinforced concrete columns are designed for equal performance levels, the required column diameters will be similar. It is concluded that precast concrete segmental columns with unbonded tendons represent a viable alternative to conventional cast-in-place reinforced concrete columns. |
