The Bang Na Expressway , officially Burapha Withi Expressway , is a 54 km long six-lane elevated highway in Bangkok, Thailand. It is a toll road and runs above National Highway route 34, (Bang Na–Bang Pakong Highway) owned by the Expressway Authority of Thailand .
The highway is elevated onto a viaduct that has an average span length of 42 meters. It is a 27-meter wide box girder bridge and was completed in January 2000. It took 1,800,000 cubic meters of concrete to build the bridge. The structure was built using a design-build contracting method and was designed by Jean Muller International.
There are two toll plazas on the elevated structure where the structure must widen to accommodate twelve lanes. It is often considered to be one of the longest bridges in the World (until 2010 the longest) but it is excluded from some lists since it does not cross a body of water for most of its length. The most major body of water that it crosses is the Bang Pakong River.