Reconstruction vs retrofitting of a bridge for sustainability

Abstract

Bridges face the risk of being damaged by natural and manmade disasters. Old bridges are more vulnerable in such situations. The common practice is removing these damaged bridges and constructing new ones. However, repairing, retrofitting and reusing damaged bridges could be economical and less time consuming and hence more sustainable than building new bridges. There are various methods to assess the possibility of improving old and / or damaged bridges using modern day techniques. This paper is a case study for using one of such assessment procedures on a damaged railway bridge in Puttalam, Sri Lanka. The bridge concerned is 34m long, single spanned, double lattice girded, wrought iron Railway Bridge, which was built about 40 years ago and damaged and displaced from its abutments by floods. The paper discusses the method used to determine the possibility of reusing the bridge by conducting a series of tests on the temporarily erected bridge and using a finite element model. It also presents results of tests carried out after the bridge was repaired and retrofitted. The results show that retrofitting has made substantial improvements to the bridge.