Seismic performance of bridge pier with integral connections

Conventional bridges supported on bearing are the most widely used technique to design and construct bridges in the 21 st century. The modern standard codes have standard guidelines to build such type of structure. However, integral bridges are the latest trend in bridge engineering, to overcome several failures of the conventional system. In integral bridges the deck is monolithically connected to the piers (substructure) and thus, eliminates the use of bearings. This type of connection increases the redundancy of the structure and thus is recognized as critical for seismic design of bridges. However, for a full integral bridge along with abutments, the backfill interaction is a concern and has many uncertainties as detailed guidelines are not made available in any of the bridge design codes. In view of this, the study investigates the seismic performance of semi-integral bridge in which only the intermediate piers are monolithic with the deck and the abutment ends are free to move on the bearings provided on the abutment cap. To illustrate the benefits of bridge pier with integral connections, a comparative study is made between existing conventional bridge and the proposed semi-integral system in terms of demands and displacements. The study includes non-linear time-history analysis to evaluate the performance of conventional pier and the integral pier under seismic loads.