Eurocode loads and the implications for the structural design of box culverts in Sri Lanka

Abstract

The Reinforced Concrete Box Culverts are drainage structures that allow to cross, small to medium scale water paths. They generally founded in soil where scouring is not an issue. The advantage of the box culvert is that it can be rested on the soil where low bearing pressures exists. Box structures are also often used in expressway construction when underpasses are needed for the traffic of by-roads that crosses the expressway embankment. The present highway structure design practice in Sri Lanka is based on the British Standard, BS 5400, that was published by British Standard Institution (BSI) in 1978 and then amended, number of times subsequently and along with the Bridge Design Manual (1991), published by Road Development Authority (RDA), the apex body of managing A & B class of roads in Sri Lanka. Since the BS codes have been superseded by BS EN (the English version of Euro Codes) in March, 2010, it is now opportune to adopt the recommendations of BS EN for the structural design of highway structures and hence box structure design will also need updating. In this paper, a detailed study has been carried out as a comparative study by considering number of possible arrangements of reinforced concrete box structures that are typically used in Sri Lanka. The reason is that BS EN allows a loading regime from which different values can be selected in contrast to the current BS based practice. The detailed analysis, with Finite Element Method (FEM) , has been carried out for different types of loading specified in the BS EN; the results have been compared with the resulting effects of currently adopted standards to find suitable loading levels that can be recommended for the adoption in Sri Lanka. The results are presented in graphical form to allow the selection of different levels of loading based on the effects on the main design parameters.