Optimal risk-based hydraulic design of bridges.

The hydraulic design of highway bridges entails the evaluation of flood hazard associated with a proposed bridge structure and the determination of socio-environmental effects of the bridge project. A procedure for treating hydrologic uncertainties is incorporated into an optimization framework to develop the optimal riskbased design of the bridge openings and the embankment heights that minimizes the total expected cost. The optimization technique used is called Hooke-Jeeves pattern search. The procedure to determine the optimal bridge design is applied to Leaf River, Mississippi. The effect of using different procedures for hydrologic parameter estimation and the effect of using different hydrologic probability models on the optimal design are examined. (A)