Online application for calculating the Backwater (afflux) caused by bridge piers. The analysis of the backwater produced by bridge piers is a topic of particular interest. The importance of this problem is due to the frequent presence of piers in the active section of waterways, both near and outside populated areas. This division often corresponds to a different structural connotation and, therefore, to a different hydraulic behavior. Often, in fact, the risks of waterway flooding are high precisely in populated areas, both due to the greater concentration of older bridges that result in a lower contraction ratio, and due to embankments (levees) that can further limit the waterway section for long stretches.
The experimental formulas used to evaluate the backwater produced by bridge piers as a function of the flow’s hydraulic characteristics and the geometric characteristics of the section occupied by the bridge are:
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D’Aubuisson’s formula (1852)
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Nagler’s formula (1918)
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Yarnell’s formula (1934)
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Al-Nassri’s formula (1994)