T-REX Sitework

SECC Crews Dig The Only Tunnel Along T-REX Corridor

A furious barrage of sitework is ongoing at Colorado Boulevard and I-25, where T-REX crews are building the only tunnel and below-grade light rail station along the T-REX corridor.

According to CDOT, Colorado Boulevard near I-25 is the busiest street in the state, carrying nearly 80,000 vehicles per day. The point at which the light rail crosses Colorado Boulevard houses several existing businesses on the west side and the expansive Colorado Center development to the east.

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Taking the light rail line above ground - as is the case at many of the other stations along the corridor - would have been detrimental to those existing businesses, so light rail designers opted for a tunnel approach to the Colorado light rail station instead.

The Colorado tunnel is 32 ft wide, as deep as 28 ft at its lowest point, and extends below grade for 2,200 ft. The covered portion of the light rail line is 609 ft long as it goes under Colorado Boulevard and arrives at the open-air, below-grade station on the east side - where it widens out to 60 ft.

According to Ben Carnazzo, segment manager for Southeast Corridor Constructors, the T-REX contractor, utility relocation in the area has been the most difficult part of the tunnel construction. SECC crews had to relocate 36-in. water lines, 20-in. gas lines and support Qwest in the relocation of three duct banks of fiber optic cabling.

"The splicing of those lines was supposed to take six months and it took nine," Carnazzo said.

More than one million cu yds of dirt have been moved at the Colorado station site so far, but the new concrete deck for the Birch Street Bridge, next to Freeway Ford, is complete and crews will realign the street this month.

The Colorado station project becomes even more complex beginning in January 2004 when crews begin replacement of all the bridges at Colorado Boulevard and I-25. The new bridges at Colorado will take about two years to complete, with the light rail station there opening in fall 2006.

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