The new light rail bridge that will span Sixth Avenue is being assembled on the Denver Federal Center grounds. Lakewood Edge photo.

When FasTracks rolls out the bridge that will span West 6th Avenue on the west side of the Federal Center, it will do so literally, closing down a stretch of the heavily traveled highway for two days.

And the Regional Transportation District plans to make the snail’s pace placement of the bridge a spectator event.

The huge span will be wheeled from its fabrication site south of the highway about 9 a.m. Saturday, April 24, and grandstands will be in place so the public can watch the slow-motion haul first-hand. The plans for the rollout are contained in a memo to RTD’s Board of Directors obtained by the Edge.

The transportation agency plans to make a major production of the move and will set up a public viewing area at the Office Liquidators lot on the north side of the 6th Avenue Frontage Road at Quail Street. The plans call for bleacher seating and the agency will distribute maps to the public about a week before the bridge starts its move.

The bridge will move somewhat faster, about 25 feet per hour, a journey that will take an estimated 30 hours to reach its destination, according to RTD. It will be moved via two eight-axle, 35-foot transport platforms.

But the traffic impacts of the roll-out are no joking matter: All lanes of West 6th Avenue will shut down between Kipling Street and the Simms/Union exits for the entire weekend, from Friday evening until Monday morning, according to the memo. Major congestion can be expected along the detours – Kipling north to West Colfax Avenue then west to Simms and south back to West 6th for westbound traffic; and Union Boulevard south to West Alameda Avenue, then Kipling north to the highway for eastbound traffic.

Folks headed to or from the mountains and foothills can take Interstate 70 westbound to avoid the detours.

The bridge “launch”, as the memo calls it, might be a slow haul, but the sight should be impressive. 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 fact sheet distributed with the FastTracks memo.

The bridge is a “clear span” design with no center pier in the freeway median to hold up the span. Instead 44 cables strung from the arch to the base provide support with an estimated breaking strength of 688,000 pounds. There are 1,950 feet of 23/8-inch cable criss-crossing the bridge.

The clear-span design will be wide enough from side pier to side pier to allow future widening of the freeway, the Simms-Union interchange ramps that pass beneath the bridge and the frontage road on the north side of West 6th Avenue.

Read more Lakewood news at Lakewood Edge.