DENVER—A 1.6-mile viaduct on Interstate 70 in Denver that has worn joints, corroding steel and cracking concrete is set for repairs—but not the $800 million in work needed to rebuild it.
The work that will start in the next week or so is described as a $21.6 million Band-Aid by the Colorado Department of Transportation. Contractors will take at least two years to replace 60 expansion joints on the bridge between Colorado and Brighton boulevards.
Besides worn joints, water and de-icing fluids have leaked through the viaduct’s expansion joints and seeped into concrete piers, girders and columns supporting the structure.
The seepage has caused reinforcing steel to corrode and swell. That expansion has caused surface sections of the concrete to crack off.
“We have reports that magnesium chloride can decrease the compressive strength of concrete up to 70 percent,” said CDOT engineer Jeff Anderson, referring to the de-icing material.
The bridge is one of 125 owned and maintained by the state rated in poor condition, but the state doesn’t have the $800 million to rebuild the viaduct now.
The viaduct was built in the early 1960s for $12.5 million. Rebuilding it would easily make it CDOT’s most expensive bridge project.
Replacing or renovating the other 124 bridges in poor condition would cost a total of $600 million.
State engineers hope the expansion-joint project will give the viaduct at least another 10 to 15 years of useful life and the state time to figure out how to finance reconstruction or relocation of I-70 in that area.
An environmental study is under way that’s looking at reconstructing the bridge or realigning I-70 and eliminating the bridge. The study is expected to be complete in about a year.
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Information from: The Denver Post,
