I-15 Northbound, 10600 South Interchange

Salt Lake County, Utah

The Utah Department of Transportation (UDOT) turned to Michael Baker to replace one of the state’s busiest interchanges, with reduced motorist and other impacts than traditional phased construction might cause.

Our team, well versed in accelerated bridge construction (ABC) techniques, found an innovative way to condense a normally nine-month-long construction project into 16 days for the I-15 Northbound, 10600 South Interchange. The solution: a construction process that would include a three-sided, precast box underpass structure that literally would be slid laterally along footings and put into place, followed by the installation of a full bottom slab. This was the first three-sided box structure ever used by UDOT.

The structure, which weighed an estimated 3 million pounds, with a 123-foot length and 22-foot height, took only two hours to slide into place from its original position, where it had been cast. Building the new structure and cast-in-place portion outside of existing traffic allowed for better access to the construction site and promoted a safer environment for workers and the public. The three-sided concrete structure was cast with a traditional forming system and didn’t require specialized equipment for construction.

The keys to the slide were simple, pre-cast concrete footing section that provided a solid and level surface for the slide system. Otherwise, the construction company would have had to construct the bridge section in three time-consuming sections over a period of nine months.