Methodology for the assessment of scour at bridge sites in Missouri

A field inspection methodology, a scour- susceptibility ranking procedure, and a data base management system were developed for the Missouri Highway and Transportation Department to use for scour inspection and assessment at bridges throughout the State. Because scour can cause bridge failure, federal statute mandates that the approximately 4,700 state-owned bridges over water be assessed for scour-related problems. The Missouri Scour Assessment Field Form was developed so that bridge inspectors from the Missouri Highway and Transportation Department could collect data at a bridge site quickly and thoroughly. The arrangement of the form allows inspectors to collect specific quantitative data at each area with a minimum of wasted steps. The Missouri Bridge Scour data base was developed to store and manipulate scour data collected during field inspections. Scour data in the data base can be updated, printed, and tabulated with other records using several criteria. A potential scour index and an observed scour index are calculated within the data base for each bridge site. The data base also may have multiple entries for a single site, providing versatility whereby recent inspections may be compared with earlier inspections to document long-term trends and changes.