Study on structural aspects of underpasses in southern transport development project

The Colombo-Matara express highway also known as the Southern Lanka Express Highways or simply the Southern Expressway is a highway currently under construction in Sri Lanka. The 126 km long highway will link the Sri Lankan Capital Colombo with Matara, a major city in the Southern Province of the Island. Construction of the highway began in 2006 and it is expected to be completed in 2010 at the cost of $600 million. When completed, it will reduce the time taken to travel from Colombo to Matara to one and a half hours from the current four hours. It is known fact that the Southern Highway and other subways linked with are normally supported by a wide range of different structures which require careful thought in selecting a suitable one for each location. In fact, these structures form a vital part of transport infrastructure and the smooth running of the network as designed. Even though, this study has been narrow down only to underpasses from the vide range of structures being used. Therefore, in this research work, it is mainly focused on to the underpasses " such as metal and concrete underpasses used in and its significant impact on the cost initiatives, suitability and the environmental impacts and etc. The technology used for the metal underpasses on this project is new to Sri Lanka. Traditionally in Sri Lanka, pre cast concrete structures are the preferred option, however, in this project, metal underpasses has also been used. The introduction of new technology requires knowledge of their structural behavior, particularly when used in combination with other materials, and their long-term durability. Over the last years, many structures have started to show signs of degradation and deterioration as a result of the high chlorate content in the air in southern Sri Lanka and some kind of crack failures due to bad, workmanship as well as lack of adequate supervision, All these issues has been discussed and concluded in this report in a precise manner based on physical observation and on literature survey. Finally, this research concludes that the use of concrete box underpasses in the southern highway is mostly substantiated with country like Sri Lanka due to its inherent characteristics and with the economy and the durability concerns. In fact, this report is a part of a post contract analysis which describes important facts that had to be emphasized in selection of the structure underpasses for Southern highway project and concluded which type of underpasses would have been used with the great economic impact to Sri Lanka