Scour around bridge piers in Oklahoma streams (FHWA-87-2) 2150

Abstract

This study consisted of a hydrographic survey and determined maximum scour around the piers at eighteen selected bridges on the Cimarron, Arkansas, and Caney Rivers. The survey was performed soon after the 50- to I 00-year-frequency flood in October, 1986. It was determined from the survey that maximum scour varied from 0.60 to 18 feet with depth of flow ranging between 0.75 to 25 feet. Visual inspection and measurement showed that a sandy river bed and clayey river bed in the three streams seemed to affect scour depth. Also, heavy damages occurred in overflow structures in flood plains rather than at piers in the main stream. Because design criteria for scour depths at piers are based mostly on laboratory work and because some bridges designed according to these criteria have failed, it is recommended that this study be extended to collect field data on the maximum scour at selected bridges over a four-year period. Field data will be collected four times a year for various high and low flow conditions. Laboratory and field data are to be analyzed and used to produce design criteria so that damages to bridge piers are minimized. Further laboratory and field data will be generated for different river-bed soils (sand, silt and clay) and for varying hydraulic conditions.