Seismic analysis and design of R/C bridge including SSI effects

This work investigates the soil-structure-interaction (SSI) phenomenon manifested during the seismic response of a reinforced concrete (R/C) bridge. We focus on a four-span highway bridge with piers of unequal height crossing a mountain valley. The bridge and its foundation system are modelled by finite elements (FE) plus the spring/dashpot/added mass discrete parameter system. A hierarchy of FE meshes is developed, starting with shell elements and ending with linear elements. Also, two basic types of foundations are examined, namely spread footings versus pile groups. Following a preliminary design of the bridge, a series of time history analyses of the combined deck-pier-foundation system are performed, the results of which are used in assessing the role of the foundation's compliance. The influence of key construction details such as pier-to-deck connection on the response is also examined. Finally, a series of recommendations are given on how to account for the ground's influence on the design of the piers.