NDOT Undertakes Inaugural Design-Build Highway Project in Las Vegas

By Tony Illia

As its first design-build project, the Nevada DOT is starting big: the $242 million, nearly 6-mi-long Interstate 15 widening through the most popular corridor in Sin City.

The 92-year-old Nevada Dept. of Transportation is undertaking its first design-build project.

Crews pour concrete for a deck on the I-15 overpass crossing the Union Pacific Railroad. Photo courtesy North Corridor Constructors

The guinea pig is a $242 million, 5.8-mi-long widening of Interstate 15 extending from the U.S. Highway 95/I-15 “Spaghetti Bowl” interchange in Las Vegas to Craig Road in North Las Vegas.

The complex, multifaceted undertaking entails intricate phasing and traffic control as well as construction of 16 new bridges, interchange reconfigurations and 406,000 cu yds of asphalt paving.

In July 2007, North Corridor Constructors LLC, a 50/50 joint-venture of Las Vegas Paving Corp. and CH2M HILL, Englewood, Colo., won the job after a two-phase, state-sponsored competition. CH2M HILL is the team's lead contractor.

North Corridor Constructors cinched the contract with an aggressive schedule and added value that included replacing, rather than widening, three aging bridges. New York City-based Parsons Brinkerhoff helped draft the bridge documents, which were 30% complete.

The 914-working-day contract carries $10,000-a-day in early completion bonuses up to $1-million. There is also $10,000-a-day in late completion penalties. The contract carries price material escalation clauses for fuel, steel and asphalt.

“Design-build allows teams to come-up with some different ideas,” says Jeff Hale, NDOT assistant project management chief. “It gives us the ability to change things on the fly as necessary.”

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NDOT previously had relied on a more traditional project approach. It, like other agencies, often uses a design/bid/build procurement method that awards contracts based on price, as opposed to best value or most-qualified. The low-bid process can create adversarial relationships between project stakeholders resulting in conflict.

Design-build, by contrast, creates single-source responsibility for construction cost, schedule and quality. The contractor and architect work together as a single entity, and collaboration, innovation and creativity are encouraged.

“The time savings is huge,” says Joseph Schroeder, North Corridor Constructors' project manager. “It will take a 5.5-year project and condense it down to three years.”

The project, which started in March 2008, will finish in March 2010. North Corridor Constructors wasted no time getting started, simultaneously performing sitework while designs were still being drafted. Even still, Schroeder says “constructability issues get addressed on paper, thereby reducing change orders and cost overruns.”

The first girder over Washington Street Bridge is erected for the I-15 widening project in Las Vegas. Photo courtesy North Corridor Constructors

For motorists, the improvements can't come soon enough. The roadway segment is sorely outdated, with portions having been built in the late 1960s. The stretch of interstate now sees over 170,000 vehicles a day or about 30% more than its design capacity.

The carefully phased and coordinated project will widen I-15 from six to 10 lanes from the Spaghetti Bowl interchange to Lake Mead Boulevard, and expand I-15 from four and five lanes to eight lanes from Lake Mead Boulevard to Craig Road. The on- and off- ramps at all four interchanges along the project route will be configured, including D Street, Lake Mead Boulevard, Cheyenne Avenue and Craig Road, while auxiliary lanes are being added between the interchanges.

Aging 40-year-old bridges at Bonanza Road, D Street and Washington Avenue will be reconstructed, and a new four-lane, .25-mi-long connecting road will link D Street and F Street between I-15 and Bonanza Road.

NDOT was forced to use the existing right-of-way for its expansion, which meant building 180,000 sq ft worth of precast mechanically stabilized earth walls and 45,000 sq ft of cast-in-place walls to maximize its real estate.

The project has 12 post-and-panel sound walls, averaging 12 ft high and extending over 2 mi. There are 710 precast sound-wall panels in total, each weighing 12,225 lbs. Other work consists of desert landscaping and barrier rail, 25,694 lin ft worth of storm drainage up to 60 in. in diameter and 72 mast light poles averaging 120 ft tall.

There also are Intelligent Transportation System improvements, such as dynamic message signs, ramp metering and closed-circuit television cameras. The project will use 90,000 ft of conduit.

The tight squeeze led North Corridor Constructors to rent two yards: one for job trailers, another for material storage and staging. Project headquarters sit on two acres at Washington Avenue and D Street. A 35-acre material storage and concrete casting yard is located near Lamb Boulevard and I-15.

Work has been broken into four segments, performed in two major phases with 300 workers and 25 subcontractors onsite.

“Traffic is a constant challenge,” Hale says. “We meet on a weekly basis to discuss traffic coordination with the cities of Las Vegas and North Las Vegas.”

North Corridor Constructors must keep a minimum of two lanes of traffic open in each direction at all times or face fines of $2,500 every 15 minutes that a lane closure occurs. The project portion of I-15 is a key truck traffic route.

Plans initially called for center lane construction that pushes traffic to the outside. But North Corridor Constructors opted for shifting both oncoming and outgoing traffic onto one side at a time. The move helped shaved 100 days off the work schedule and eliminated an additional project phase.

The project additionally saves time by using cast-in-place box-girder bridges, reducing falsework and speeding erection times. The southeast ramp over D Street is longest of all the box-girder bridges at 424 ft, while the I-15 mainline over Lake Mead Boulevard is widest at 164.6 ft.

The job also has four T-bulb girder bridges, including the 172.5-ft-long, 250.5-ft-wide I-15 over Bonanza Bridge. The two-span structure requires 44 girders that average 70,000 lbs a piece.

The project remains on schedule and within budget.

Key Players

Owner: Nevada Department of Transportation
Design-Build Contractor: North Corridor Constructors LLC
Engineers: Parsons Brinkerhoff; Jacobs Engineering; HDR Inc.
Landscape: Design Workshop; Amazon Construction
Subcontractors: Olson Precast Co.; Steel Engineers Inc. LAM Contracting LLC; Las Vegas Electric; Rinker Materials West LLC; DYWIDAG Systems Intl. USA

Useful Sources

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