What are the Criteria for Selection of Ideal Bridge Site?

It is necessary to select an ideal bridge site at which the bridge can be made economically. As construction of a bridge requires a heavy investment, the bridge site should be selected wisely. A poor bridge site may increase the project's cost, making it susceptible to damage, in the long run, thus decreasing the life span of bridges. Thus, the following are the factors that require attention while selecting a bridge site.

1. The river reach should be straight.
2. There should be uniform & steady flow in the reach.
3. The river banks should be stable.
4. The width of the river channel should be minimum.
5. The site should be sufficiently away from the confluence point.
6. There should not be the necessity for extensive river training works.
7. There should be the availability of hard strata or non-erodible foundations for the bridge.
8. There should be no excessive scouring & silting at the bridge site
9. There should be a minimum obstruction to natural waterways.
10. The bridge axis & river flow direction should be at a right angle.
11. The bridge axis should align with the centerline of the approach road.
12. The bridge should be absolutely on level. If it has to be in gradient, it should comply with that of the roadway at both ends of the bridge.
13. There should be sufficient clearance for high flood level (HFL).
14. Absence of excessive underwater construction works.
15. There should be the availability of construction materials.