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Fast Fix 8, the $62-million project to replace eight Interstate 40 bridges in Nashville during weekend highway shutdowns, finished on Dec. 4, seven months early, which the state credits in part to its first use of construction manager-general contractor project delivery. Construction, which started in April, was not set to finish until next June.

The Tennessee Dept. of Transportation (TDOT) named Kiewit Infrastructure Group as construction manager and Gresham, Smith and Partners as project engineer. “We all started early” in October 2014 to complete design and set schedule milestones—including working around availability of large cranes—and tracked schedules daily, says Marc Rothwell, Kiewit project manager. The team, which included material suppliers IMI Concrete and AFCO Steel, removed and replaced the eight bridges built in 1968 during weekend highway closures that would allow crews and equipment full access to each site and to a pair of fabrication yards in nearby medians, says Will Reid, TDOT director of construction.

The 4,000-ft stretch of highway carries more than 140,000 vehicles daily. Traffic was rerouted to I-65 during the closures.

Reid says the project team worked with Middle Tennessee State University’s Concrete Industry Management program to develop a concrete mix that would reach 4,000 psi strength in four hours and could be mixed in a plant for truck delivery. Having the contractor on board from the start also helped mitigate risk, he says. “If you have mitigated risk, in a lot of cases, you’ve saved time,” adds Reid. The fast-setting concrete allowed a coat of spray-on waterproofing mix to be applied before the asphalt was laid.

TDOT did a “test run” of a road shutdown for bridge removal and replacement last year when it removed and replaced a bridge on heavily traveled SR 254 in Nashville. Only 11 of 13 planned shutdowns were needed for the I-40 project, with work finished early each time, allowing some extra repairs before reopening the highway, Reid says. The CM-GC approach now will be used in construction of three bridges over I-240 in Memphis and on another state project not yet selected, he notes. TDOT did not pay an incentive for early completion, says a spokeswoman.