Laboratory Sensitivity Study of Hydraulic Parameters Important in the Deploymentof Fixed-in-Place Scour-Monitoring Devices

摘要

INDOT is considering the deployment of fixed scour-monitoring instrumentation aspart of a systematic response to the problem of scour around bridge piers. Fixed-in-place automated scour-monitoring devices measure the depth of scour at the point where they are installed. Unless they are installed at the location where maximum scour occurs, their readings may give a misleading estimate of scour potential. This raises a number of technical issues concerning their effective deployment and the interpretation of the collected data, which should be resolved in order to maximize the benefits to INDOT from using these monitoring devices. These include the location of maximum scour under different pier configuration and hydraulic conditions, as well as possible effects due to pier skewness and exposed footings. This report describes laboratory experiments that were performed to study these issues for various flow conditions and pier configurations. The experiments were conducted in a straight channel of rectangular cross-section located in the Hydromechanical Laboratory at Purdue University. The pier geometry was the same in all experiments, and was chosen to be similar to that of a prototype pier (in the US 52 bridge over the Wabash River), though exact scaling was not attempted. Both single and double (i.e., one upstream and one downstream) piers were studied. In general, for piers