SEISMIC CAPACITY OF RETROFITTED LOW-STRENGTH CONCRETE BRIDGE PIERS

Abstract

This paper presents seismic performance of two large size models using low strength concrete (LSC). A study after October 2005 earthquake in Pakistan revealed that bridges damaged were categorized using Low Strength Concrete (LSC) due to various reasons. The tests for subject evaluation were carried out on 1:4 scaled models of LSC circular bridge pier under a physical load of 3015.7 kN (678 kips). These models were subjected to cyclic lateral loads and free vibration tests to determine changes in dynamic properties of the system for variation in loading and drift levels. The models were first tested in their original state till their failures resulting in damages at the potential plastic zones, thereafter the damaged columns were repaired and confined with Carbon Fiber Reinforced Polymer (CFRP) and tested for their recovery of strength and ductility. A comparison of the test results of the models in both original and retrofitted conditions has indicated that even the damaged columns after CFRF retrofit can be made to recover their original strength and improved ductility to withstand even larger potential earthquakes.