Construction of concrete bridges without expansion joints in Sri Lanka

Abstract

A structure would be more sustainable if maintenance problems and associated costs are minimized. Most of the concrete bridges have been constructed in Sri Lanka with expansion joints. It results in frequent maintenance problems and associated maintenance costs, and consequently affects the durability of the asphalt pavement and impairs the ride quality as well. It is a current issue faced by RDA maintenance unit. Therefore, avoiding expansion joints will not only improve the durability of the bridge and pavement, but also results in zero maintenance cost. Expansion joints are provided to release stresses caused by movements of bridges due to the temperature variation. The temperature profile can be divided into two parts such as uniform temperature variation and non-uniform temperature variation. Uniform temperature variation causes the bridge to expand linearly while nonuniform temperature variation heats each fiber differently. Non-uniform temperature gradient can be categorized into two parts such as positive temperature gradient, which is due to rapid heating of the top fiber than the underneath fiber ; and negative temperature gradient, which is due to rapid cooling of the top fiber than the underneath fiber . When the movement caused due to the temperature changes is restrained, additional stresses would be developed in the bridge. However, the structure would be capable of withstanding those stresses if these stresses are within a reasonable range. In Sri Lanka, daily temperature variations and maximum temperature rise are not too high compared to other countries like India and Australia. Therefore, it is possible to avoid expansion joints in concrete bridges in Sri Lanka. There is no specific standard in Sri Lanka to obtain temperature values for the calculation of thermal loading except Bridge Design manual, RDA. In Sri Lanka, temperature differences for bridges can be obtained from Figure2.4 in Bridge Design manual, RDA, which is similar to Figure 9 in BS5400. These values may not be suitable to be adopted in Sri Lanka as the climatic conditions in the United Kingdom are not similar to Sri Lanka.