Evaluation of Damaged Prestressed Concrete Bridge Girder and it’s Retrofit

Abstract

The Highway is most important mode of transportation infrastructure facility used in our country. Nepal, being mountainous terrain to plain terrain with plenty of rivers and streams, construction of cheapest means of transportation like highway becomes difficult. So, number of bridges required to cross the rivers and streams for highway. Prestressed concrete is a method for overcoming the concrete's natural weakness in tension. As a result of both accidental and intentional events in connection with important structures all over the world, explosive loads have received considerable attention in recent years. In my thesis I had selected Surai-Naka prestressed concrete bridge as a case study, which has been blast by terrorist few year back and some part of it has been damaged. This Surai Naka prestressed concrete bridge is very important, as it is only one bridge for East West highway of Nepal. So using computer application, we can evaluate the strength or say capacity of this bridge so that developing country like Nepal can save this important bridge depending on its capacity. During this research work , Field survey was carried out for the damage condition of bridge. I observed that anchorage block of left main girder was damaged and two number of tendon was seen totally damaged and will not be workable. One tendon was slip about 80 mm inside. Using SAP ( version 10), 3-D model was prepared having solid element. Shell element and frame element for lane load. Class A and 10 wheeled truck load is taken for loading which is in real practice. After analyzing the model with normal and damaged conditions, different stress values are obtained. From this lane bridge was seen to allow for single traffic only if not retrofitted. retrofitting with CFRP, this Bridge regains its original strength so that this bridge got nelife and can play important role in national east west highway.