Smart Scour Countermeasures

completed

Bridge pier scour is a major concern; it is a dynamic phenomenon that varies with water depth and angle of flow, pier shape and width, and other factors. If scour at a pier can affect the stability of a bridge, countermeasures to protect the pier should be considered. The current design philosophy in the hydraulic engineering circular no. 18 (HEC-18) to estimate scour at bridge piers does not recommend using countermeasures to protect the pier as part of the design. The reason for this approach is that important data to evaluate the performance of countermeasures on a continuing basis is missing. Comprehensive data on monitoring the performance of scour countermeasures for pier protection is needed before a change in design philosophy can be considered. Current policy in the United States considers riprap placed at bridge piers to be only a temporary countermeasure against pier scour. Federal guidance requires that riprap placed at bridge piers be monitored periodically by visual inspection or by fixed instruments. This policy stems from the challenge in adequate sizing of riprap to withstand the turbulence and hydraulic stress generated in the vicinity of a bridge pier under flood-flow conditions. Therefore, the use of smart countermeasure can increase the confidence of using countermeasure around bridge piers as well as abutments.