Many people, indeed many engineers, who are not familiar with the subject think that constructing a bridge across a river is entirely a problem in structural engineering. They assume that the bridge opening can be made so large that it will completely span the river at such a height that floodwater will never rise anywhere near the deck. If this was always true there

The designer should have first seen and studied many bridges in the course of a long learning process. He should know what type of beam may be suitable in the available conditions, either a beam bridge an arch bridge or a suspended one. He should also know the influence of foundation conditions on the choice of spans and structural systems etc. hence, the designer