Southern Transport Development Project Package 1 of Sri Lanka


Southern Transport Development is the first highway project as required by Sri Lanka’s City Overall Development Strategy. It is located southwest of Sri Lanka with a overall length of 120km connecting the capatical Colombo and the second largest city Galle.

The roadbed is gravel cushion and the pavement is asphalt concrete. The standard width of the pavement is 20.5m and is designed to have dual 2-lane carriageway and to allow for a possible upgrading to dual 3-lane standard in the future.

This project comprises the design and construction of Package 1 funded by JBIC. The total length is 34.5km starting from KOTTAWA 20km south of Colombo to Dodangoda. The major construction elements include the following:

  1. Two grade separated interchanges (I/C), at Dodangoda (Km 34+800) and Welipanna (Km 46+000).
  2. One continuous box girder bridge at Bentota Ganga (Km 53+300, center span 70m, overall length 700m).
  3. One simply supported I-grider river bridge at Welipenna (Km 45+500, 4 spans, overall length 150m).
  4. Numbers of other structure are: one river crossing, eight underpass bridges, eight overpass bridges and 63 box culverts. Various soft ground treatments over nearly all fill areas.