Battling monsoons, heat, live traffic and subpar soils, a joint-venture team expects to complete 30 miles of a Phoenix-area freeway expansion in just eight months—adding another reason for the Arizona Dept. of Transportation to embrace design-build as it constructs projects to cope with growing traffic.
A team of Kiewit Corp. and Sundt Construction holds the approximately $90-million contract to add 30 miles of high-occupancy vehicle lanes to Loop 101 between state Route 51 and Interstate 10.
“To do this many miles in [nine] months is pretty exciting,” says Steve Mishler, ADOT project manager. “Typically, this project would have been broken up into five pieces, and I would have been given 18 months just for design and a year and change for construction.”
Instead, Kiewit/Sundt, with designers Parsons Corp. and URS Corp., worked with 10% to 15% design documents to start construction after receiving the notice to proceed in January. The project, which brings the entire region's carpool network closer to full build-out, is scheduled for completion in late October.
The team had the flexibility to treat poor subgrade soils with a variety of methods.
“We utilized geogrids, excavation and recompaction, and lime stabilization,” says Travis McCarthy, Sundt deputy project manager. “We first started with excavation and recompaction, but the project wouldn't have generated enough material for all the areas. Once we exhausted that, we went to lime stabilization. But to pave as much as we did, we had to work in multiple locations—so we went to geogrid operations.”
Depending on the section, the team chose the most economical or most practical solution.
Co-Location Speeds Document Approval
Thanks to co-location, a principal feature of design-build, ADOT officials and their general engineering consultants were able to review and approve documents within days. “We started off averaging about three days [for review turnarounds],” says McCarthy, “and now we're down to 2.4 days.”
Despite poor soils and harsh weather conditions such as monsoons and heat, the overall construction was straightforward, says Allen Mills, Kiewit project manager.