Ranjith Dissanayake
University of Peradeniya
Sri Lanka
Title: Green Construction: Reuse of Materials in Retrofitting of Damaged Bridges
Biography
Biography: Ranjith Dissanayake
Abstract
Building new bridges generally consumes more resources and time than repairing and retrofitting of damaged bridges. Therefore, the latter can be considered more sustainable. However, proper methods are necessary to assess the level of damages and to verify the fitness of such bridges prior to repair and retrofitting. In the assessment, there are two important criteria to consider. One is the amount of fatigue damage to the bridge due to usual past vehicle loading and hence the remaining fatigue life of the bridge. The other is the magnitude of damage caused to the bridge by the unexpected loading. The case study is about a 34 m long, 5.2 m wide, 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 bridge was then placed on temporary timber abutments for several years. Then an analysis was done by modeling the bridge and validating the FEM by using results of a field loading test. Both static and dynamic loading tests were carried out. The cost for retrofitting work and constructing new reinforced concrete abutments was much less than that for constructing a new bridge. Therefore it was decided that rehabilitation of the bridge with necessary retrofitting work is more sustainable than demolishing it and constructing a new one. The bridge is now in use after being repaired, retrofitted and placed on new abutments.