“People need to understand the importance and seriousness of infrastructure,” said Jimmy Kim, PhD, associate professor of structural engineering at the CU Denver College of Engineering and Applied Science and lead author the study. “There is an assumption that a bridge will stand forever and that’s simply not true.”
Kim along with co-authors Wesley Marshall, PhD, PE and Indrani Pal, PhD, both assistant professors of civil engineering at CU Denver, the leading public research college in Denver, examined the causes of the flooding and its impact on infrastructure.
...The rain began on Sept. 9, 2013 and didn’t stop until the 16th. In just days, places like Boulder County received three-quarters of its yearly precipitation. Bridges collapsed, roads failed and homes were swept away. According to the study, 120 bridges now need structural repair. Many were damaged by rushing water which washed out backfill soil and exposed bridge foundations.
Kim said new `scour control’ methods, aimed at reducing these washouts, should be developed to help bridges withstand future flooding. “You can do that by upgrading existing piers (columns) supporting the bridge or changing current design approaches” he said. “The Colorado Department of Transportation is currently working on improving scour design for bridge structures.”
...In Colorado, the report card says, 70 percent of major roads are poor or mediocre and 566 bridges are structurally deficient. “Reconstruction is very expensive and should be the last resort,” Kim said. “But we can repair or strengthen existing systems less expensively. We are looking at a growing national problem, one that will only get worse if we ignore it.”...