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Pecos over I-70 Project Featured in ENR Mountain States

Wednesday, June 25, 2014

In its second feature article on the project (the first appearing in the July 30 edition), ENR Mountain States reported on the many innovative solutions delivered in the Pecos over I-70 Accelerated Bridge Construction (ABC) project. ABC projects aim to minimize the impact on the travelling public for the affected area by reducing onsite construction time. RockSol provided structural plan review, safety critical review, structural inspection including post-tensioning, and quality assurance materials testing on this project. Pecos Street reopened last Labor Day weekend.

· Challenge: Seven percent of traffic at the intersection is heavy-truck traffic, in contrast with the typical four percent. Also, previous alignments on Pecos Street created a “pinch” at exits forcing trucks to make wide turns to exit. Innovation: Place multi-lane roundabouts on either end of the bridge and eliminate traffic signals.

· Challenge: A traditional delivery method would cause big public impacts in terms of traffic flow and scheduling. Innovation: Deliver the project via Construction Manager/General Contracting CM/GC, a relatively new delivery method for CDOT on major highway projects which pairs designers and builders under separate contracts.

· Challenge: The typical bridge replacement process would cause multiple delays for closures. Innovation: Construct and place the bridge using an ABC method using Self-Propelled Modular Transporters, another first in the state. This allowed the bridge to be rolled into place over one 50-hour weekend closure, minimizing impacts to I-70 and reducing construction time by eight months.

· Challenge: Right-of-way put the roundabouts close enough together to make building a straighter, girder-type bridge impossible. Innovation: Design a cast-in-place, post-tensioned structure with a bow-tie shape, a first in Colorado.

· Challenge: School-children needed to cross the interstate and ramps to get to Remington School on the south side of I-70. Innovation: “The team opted to create a ‘pedestrian-safe travel path’ through the area by placing a separate pedestrian bridge west of the vehicle bridge and adding special traffic signals at the ramps. The new HAWK, or High-Intensity Activated CrossWalK signals, use a pedestrian-activated, four-tier system—green, yellow, yellow, red. They give cars more time to slow down at pedestrian-busy cross streets but don’t create a long traffic queue in the roundabouts.”