Project duration: 1983 – 1989.
A Preliminary engineering report was prepared complete with cost estimates covering the economic feasibility of replacing obsolete single-lane bridges on Raxaul-Kathmandu Highway. Nineteen possible bridges replacement were evaluated and prioritized.
After client review of the report, seven bridges were selected for replacement with partial funding from the International Development Association (World Bank). The bridges were designed and tendered as a single contract for construction by international contractors, which resulted in low bid of approximately US$ 2.5 million.
The new bridges consists of two lanes for traffic plus sidewalks on one or both sides, and are designed for HS-20 live loading. The new concrete bridges are 22 to 108 m long and replace low-capacity, steel truss bridges. Due to the importance of the highway, traffic was maintained at all times during construction.
As maximum re-use of shuttering for the post tension T-Beams is desirable, the cross-section chosen for the 30m simple spans on four of the bridges was also used for the three 36m spans at Karra Bridge by Utilizing two stages post-tensioning. For Karra Bridge, the first stage was applied to the I-Section for dead and construction stage loading and the second stage to the composite section including the cast-in-situ deck slab. This design method resulted in the production of some 40 I-beams from the two sets of identical shutters for the five southern bridges.