NORMAN — One of Norman’s primary gateways welcoming visitors into town is about to get a major facelift. Construction on the I-35 and Main Street interchange begins Monday, according to city staff reports and the Oklahoma Department of Transportation.

Allen Contracting will begin installing traffic control devices to adjust traffic on I-35 and on Main Street starting on Monday.

“They’ve got to barricade off safe work zones,” said Scott Sturtz, city engineer. “There will be no permanent lane closures on I-35.”

Traffic on Main Street will remain in its current configuration until the north half of the new bridge is completed.

The $35 million construction project was awarded jointly to Allen Contracting and Manhattan Road and Bridge of Oklahoma City. The project has an estimated completion date of March 2014.

“They will be working more than eight hours a day on this project. It’s an ODOT administered project,” Sturtz said. “There will be times they will be working between 9 p.m. and 6 a.m. It’s written in the contract that way. They’re trying to minimize the disruptions on I-35.”

When complete, the interchange will be one of the first of its kind in the state.

The single point urban interchange or SPUI will be designed to use space more efficiently and allow for the safe movement of higher volumes of traffic within that limited space. Transportation officials report that these interchanges safely maximize the flow of traffic where streams of traffic merge or separate.

Oklahoma’s first SPUI has been completed at Interstate 40 and Morgan Road. Norman will have the second SPUI in the state.

Construction plans are designed to keep traffic disruption to a minimum during the overhaul of the interchange.

“They’re going to build half a bridge at a time over I-35,” Sturtz said.

Initially, the contractors will build half of the new structure, then they’ll put the traffic onto it. Next they will tear down the existing structure and build the other half of the new structure.

“They’re supposed to maintain four lanes of traffic,” Sturtz said.

The SPUI style of interchange was selected for I-35 and West Main Street by ODOT and the Federal Highway Administration following an extensive Environmental Assessment process. Norman residents participated in the process for creating this gateway, which will include aesthetic enhancements.

Artistic enhancements at I-35 and Main Street will depict the Land Run of 1889, along with other embellished concrete bridge elements. Other betterments at the exchange include overhead lighting, fencing and sidewalks. Landscaping will be maintained by Norman, and the words “City of Norman” etched in concrete will welcome visitors to the city.

“In an effort to speed this project along, they’re also offering incentives for early completion,” Sturtz said.

The ODOT construction contract allows the contractor to earn an early completion incentive of $15,000 a day with a maximum of 100 days.

“This contractor has already told us that he’s motivated,” Sturtz said. “He’s wanting to make that extra money.”

Four lanes will remain open to traffic on I-35 but there will be temporary lane shifts. The reconfiguration of the ramps for the new Main Street Bridge will require that the cloverleaf ramps are closed for the duration of the project.

All outside ramps will remain open, only closing temporarily to install detours.

The project will involve replacing the existing Main Street bridge and interchange with the SPUI which includes longer on and off ramps at I-35 and a wider Main Street Bridge. The SPUI will allow large volumes of traffic to negotiate the area using a single set of traffic lights mounted at the center of the bridge.

In addition I-35 will be widened for one half mile north and south of Main Street from four lanes to six lanes as well as widening Main Street from four lanes to six lanes where it crosses over I-35.

Joy Hampton366-3539jhampton@normantranscript.com

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