It’s hard to know for sure, but chances are more than a few Denver motorists have been singing “here we go loopty-loo, here we go loopty-lie” as they leave southbound I-25 to go eastbound on U.S. 36 on an interchange that has a number of major arteries going in different directions, creating major traffic hazards.
“It’s a very tight loop,” said Daryl Miller, project engineer for the Colorado Department of Transportation. “There are a couple areas around the interchange that aren’t very safe.”
However, that is all about to change — and a lot faster than anticipated thanks to a successful bond sale last May that raised $535 million for highway improvement projects in Colorado. Because of the availability of funds, the I-270 extension, which includes the aforementioned loop, was originally scheduled to begin in 2002, but was moved up to August 2000. Colorado voters approved the sale of the bonds in an election last November. Several other bond issuances are scheduled in years to come with the potential of raising a total of $1.7 billion for other highway projects in the state.
“In the past decade, Colorado’s population has grown by 20 percent and traffic volume by 40 percent. Fortunately, bonding allows us to start attacking many of the traffic problems related to growth,” said Colorado Transportation Commission Chair Dan Stuart.
Miller said the early start date allows CDOT to take advantage of Colorado’s healthy economy. “The economy is fantastic now. Prices are good and, even though there’s a labor shortage, we have a good-sized labor pool in Denver. It’s always cheaper to do things as early as you can,” added Miller.
The $25-million I-270 extension project will reconstruct the I-270/I-76 interchange, rebuilding ramps to improve safety and traffic efficiency.
Overall, seven structures will be built. The two bridges on eastbound and westbound I-76 over I-270 will be replaced. The existing left-hand ramp from westbound I-270 to westbound I-76 will be replaced with a right-hand ramp and three new structures will be built to take I-76 over this new ramp. A n additional ramp will take traffic from westbound I-270 to eastbound I-76 with a new bridge over York Street and, another bridge will be constructed to accommodate a future ramp from eastbound I-270 to eastbound I-76.
I-76 will be reconstructed in concrete from east of I-25 to York Street to include acceleration/deceleration lanes. Improvements made to York Street include extending the four lanes to the south. Although this is an area of heavy traffic, it is expected that lane closures and traffic restrictions on both I-270 and I-76 will take place Sunday through Thursday nights with some weekend closures as necessary.
The project will include 30,000 cu. yds. of concrete for the bridges and 110,000 sq. yds. (100,584 sq m) of concrete for surfacing. Fifteen thousand tons (13,500 t) of asphalt also will be brought in to surface part of the roadway.
Miller said the two I-76 bridges that will take traffic over I-270 will each be about 332 ft. (101.2 m) long and will replace existing bridges. The three new bridges, one making room for a new ramp and two over York Street, are all 200 ft. (60.9 m) long.
Because the revamped interchange is near residences and small businesses, two 10-ft. (3 m) high sound walls will be built. On eastbound I-270, the sound wall will be 800 ft. (243.8 m) long and the sound on I-76 just to the east of York Street, will be 600 ft. (182.9 m). Both walls will be masonry.
As for embankment, Miller said the 493 cu. yd. (450.8 m) required is available on site.
Hamon Contractors Inc. of Denver is the construction contractor for the project, which is expected to take three years.
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