Abstract :
This study discusses the hydrological and hydraulics study for bridges/culverts in order to estimate the 100-year water surface elevation at a given project site. Bridges (and sometimes very large culverts) are very expensive hydraulic structures which usually have a design period of 100 years. Most bridges fail due to overtopping of flood water. In Pakistan, due attention is usually not given to this important study, that result in the failure of bridges before reaching their design periods. In the current scenario, no one can deny the importance of this study especially after the destruction of bridges due to recent floods (July 2010) in Pakistan. This study is focussed on various hydrological and hydraulics procedures to calculate the 100-year flood discharge at a culvert site on Long Branch located under Guinea Road in Virginia, USA. For this purpose, we used Anderson method to estimate the discharges for various return periods. The bridge engineer can then fix the road level for the culvert keeping in view a suitable free board value. Such a structure will not be overtopped by a flood that has a recurrence interval of 100 years.
Keyword :
Bridge, Culvert, Return period, Overtopping