SEISMIC VULNERABILITY ASSESSMENT OF RC BRIDGE WITH UNEQUAL PIERS USING ENERGY-BASED DAMAGE INDEX

Bridges are critical links in highway transportation system and damage to bridges during earthquakes may have severe consequences in terms of impaired emergency response and economic loss. Seismic vulnerability of bridges is strongly dependent on the behaviour of their components like piers, bearings, joints, side columns and shear keys. In this paper, an energy-based damage index, previously proposed by the authors is used for seismic assessment of columns and bearings of a skewed-RC bridge with unequal pier height. The bridge has three spans and multi-column bents. The energy-based damage index is calculated for the bridge bearings and the piers and damage curves are developed for the bridge bearings and columns. The damage levels of the bearing and columns for design PGA values is also determined. The results show that the bearings, which are located on the side columns, are more vulnerable to earthquake excitements than the bearings on the long columns. For a constant PGA value, the damage levels of the side piers are higher compared to the long piers for all records in accordance with the damage values of the bridge columns. Moreover, for the design acceleration, the damage curves show that in some records the bridge piers reaches the moderate damage levels and the bearings are in failure threshold, which means the bridge components cannot withstand the design acceleration in these records.

Keywords:

Damage index , RC bridge , IDA , Piers , Elastomeric bearings