The flooding that devastated parts of Colorado in September 2013 might have been less destructive if the bridges, roads and other infrastructure had been upgraded or modernized, according to a new study from the University of Colorado Denver.

“People need to understand the importance and seriousness of infrastructure,” says Jimmy Kim, Ph.D., 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.”

The rain began on Sept. 9, 2013 and didn’t stop until the 16th. Places like Boulder County received 75% 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 says 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 says. “The Colorado Department of Transportation is currently working on improving scour design for bridge structures.”

The researchers also suggested improving roads made of concrete or bituminous material like asphalt since they often disintegrate when flooded. Kim says fiber, nano-particles or polymeric admixtures could be added to these construction materials to increase tensile strength and flexibility while reducing cracking.

The researchers say that from 1980 to 2007, about 90% of all global disasters were caused by flooding either by rain, tsunami, hurricane or some other natural event.

“Reconstruction is very expensive and should be the last resort,” Kim says. “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.”

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