Highway reopens early after crews set bridge in place

Light rail bridge sets astride West 6th Ave., allowing the highway to reopen a day earlier than planned.

LAKEWOOD – A new light-rail bridge rests astride West 6th Avenue and traffic scurried along the busy highway Sunday, more than 24 hours ahead of schedule after FasTracks construction crews rolled the span into place without incident late Saturday.

Westbound lanes of West 6th opened up between Kipling Street and the Simms’ Union overpass opened at 11:30 p.m. and eastbound traffic began rolling underneath the new bridge about an hour later.

It took crews only 14 hours to move the bridge across the highway, an average speed of 20.4 feet per hour. The rollout was expected to take about 30 hours.

The move, which a Regional Transportation District spokeswoman said went “without incident, began at 2:30 a.m. Saturday and was more than halfway compete within 6 hours.

“We are making excellent progress,” Jim Starling, RTD’s West Corridor Project Manager said Saturday.

The bridge was designed to be assembled adjacent to the highway, then moved into place instead of being built on-site, a decision the transportation agency believes spared motorists months of traffic headaches.

“The joint decision by the Colorado Department of Transportation, RTD and its contractor to completely close the highway for one full weekend reduced what could have been months of lane closures,” according to a statement released Sunday by RTD spokeswoman Brenda Tierney. “By assembling the bridge on the side of the highway over the past several months and rolling the bridge into place over a weekend substantially minimized the impact to commuters traveling on 6th Avenue.”

“If the bridge had been constructed in place over the highway, we would have had to impact traffic on 6th Avenue many times over the course of construction instead of just one weekend as we are doing,” Starling said “But safety is always the utmost priority.”

After snowy weather forced a postponement in the original late April rollout date, FasTracks crews move earmarked Saturday for the move of the West Corridor light rail project’s signature double-track bridge.

Construction crews have spent the past several months assembling the tied-arch, weathered steel bridge just south of and will move the span to its final position over the highway aboard a “dolly” made of two eight-axle, 35-foot platforms. The bridge traveled over guided rollers pushed by hydraulic rams capable of producing as much as 270,000 pounds of force per square inch.

Although the move was far from a NASCAR-pace, hundreds of on-lookers showed up as early as up Friday night and some spent the night in nearby parking lots to make sure they had a good vantage point.

RTD installed bleacher seats for public viewing in a parking lot on the northeast corner of Quail Street and the 6th Avenue Frontage Road for Saturday’s crowd.

“That’s the only ‘formal’ day, the only day we will actually have bleachers out there and information and people from RTD there to answer questions. But we have leased the parking lot for the whole weekend. So if people want to drop by on Sunday and just stand there and look, that’s fine,” Tierney said.

The bridge’s “clear span” design – with no center pier in the freeway median – allowed the bridge to be built off-site. Instead of a center support, the 44 cables strung from the arch to the base provide. There are 1,950 feet of 2 3/8-inch cables, each with an estimated breaking strength of 688,000 pounds, criss-crossing the bridge.

It is one of only two or three clear-span bridges in the U.S.

The bridge is 286 feet long, 43 feet wide and is 65 feet tall from crown to base. Its structural steel components weigh a total of 1.2 million pounds. The high-strength steel is “weathered”, turning brown as a “protective oxide coating” forms, eliminating the need for painting according to a FasTracks fact-sheet.

The 12.1-mile West Corridor light rail project is the first of the FasTracks corridors to start construction. The West Corridor line will operate between Denver Union Station in downtown Denver and the Jefferson County Government Center in Golden; serving Denver, Lakewood, the Denver Federal Center, Golden and Jefferson County. The corridor is scheduled to open to the public in 2013.