- A Comparative Study of Real Time Measurement and Estimation of Scour at Bridges due to Flood
- Yoon, Yong-Nam ; Ho, Jung-Seok ; Lee, Jae-Soo ;
- Journal of The Korean Society of Civil Engineers, volume 17, issue 2_3, 1997, Pages 225~225
Abstract
The objective of the present study is to investigate the mechanism involved in the local scouring and infilling around a bridge pier during a flood. The river bed elevation changes at bridge piers are measured on a real time basis throughout a flood event by a fathometer. and the maximum scour depths at bridge piers are estimated with 2-di-mensional hydrodynamic model, TABS-MD and C.S.U. equation. which is a popular formula for calculation of the local scour depths. As a result, the estimated scour depths are found to be much larger than the measured because the empirical scour depth formulas, such as C.S.U. equation, are generally developed under a steady flow condition in a laboratory channel, whereas the scouring process in rivers during a flood occurs under unsteady flow conditions. Therefore, an empirical formula always overestimates the actual maximum scour depth around a pier, which is on a safe side in view of the bridge foundation design. It is suggested that more studies should be accumulated to improve the estimation method of maximum scour depth around a bridge pier.