Legacy Parkway Northern Interchange

By Bruce Higgins | September 28, 2010

The Legacy Parkway on the north side of Salt Lake City has been a major undertaking that will relieve commuter traffic as well as aid traffic on Interstate 15 from the north, where traffic travels to Interstate 80 westbound or to the Salt Lake airport.

Utah Department of Transportation is aggressively trying to offer commuters more choices. The parkway has been successful in diverting about 45,000 vehicles, or 30 percent, of the I-15 rush hour traffic. The entire Legacy Parkway route is 14 miles, running from North Salt Lake to Farmington, UT.

The Legacy Parkway was originally proposed in 1996; however, the concept actually began with community leaders in the 1960s. Following years of delays, a court settlement in 2005 allowed the Legacy Parkway project to proceed on a fast-track schedule. Funding for the Legacy Parkway was provided from the state's "Centennial Highway Fund."

The $685-million project was designed to respond to the terms of the environmental impact statement by avoiding as much wetland impact as possible, as well as meeting the negotiated agreement to create a unique parkway look and feel. The parkway is not your typical highway. For one thing, it is a four-lane roadway with a 55-mph speed limit, compared with I-15's 65-mph limit. And unlike the I-15 route, the parkway was designed to be artistically interesting and delightful for the motoring public using the roadway. A trail system runs along parkway, served by more than a half dozen special parking lots. The trail system serves to accommodate foot, bicycle and equestrian traffic.

UDOT broke the parkway project into three segments prior to construction and awarded all contracts in 2006, with the same timeframe to complete construction. Each segment had approximately $90 million to $100 million in construction costs.

  • Segment 1, 2200 North &I-215 to just north of 500 South in Bountiful, with Ames Construction the contractor and H.W. Lochner as designer.
  • Segment 2, north of 500 South in Bountiful to South of Glovers Lane in Farmington, with A&W Construction (Ames and Wadsworth Brothers) contractor and Carter Burgess as designer.
  • Segment 3, Glovers Lane to the I-15/US-89 Interchange, with Clyde-Geneva Constructors contractor and Horrocks Engineers as designer.

The teams were allowed 10 months for design, with construction starting December 2006.

UDOT awarded the $100-million Segment 3 contract to Clyde-Geneva Constructors, a joint venture. Segment 3 is the shortest, most complex of the projects, totaling 2 miles from just south of Glover Lane to the I-15/U.S. Highway 89 interchange in Farmington.

The Clyde-Geneva joint venture team is composed of two sister companies, Springville, UT-based W.W. Clyde & Co. and Orem, UT-based Geneva Rock. Clyde, the original Clyde Company, was founded in 1926. In 1954, Geneva was formed to specialize in the production of processed materials for the entire construction industry. In 1968, the Geneva organization, recognizing the demand from smaller projects in the metro Salt Lake City area, established a construction division.

Segment 3 has nine major structures, including a pedestrian overpass. The major quantities include 40,000 cubic yards of concrete; 100,000 linear feet of 16-inch, closed-end steel pipe piling; and 85,000 tons of asphaltic concrete for pavement. Besides the major interchange structures, the project includes two local cross street overpass structures built with prestressed concrete girders. The remaining six traffic structures are designed with structural steel girders.

The flyover designated as C-866 is a unique design that has post-tensioned pier caps integrally cast with the girders. This means that there are no bearing devices on the pier caps and no expansion joints over any of the piers. The only expansion joints in the bridge deck are at the abutments.

In order to cast the pier caps integrated with the steel girders, it was necessary to provide temporary support of the girders pending the placement of the post-tensioned concrete with the pier caps. The overall length of the structure is 1,300 linear feet with three long spans. The center span is 243 linear feet. Part of the design factor with the piers fixed to the girders requires that the piers are not skewed parallel to the I-15 lanes passing underneath the center span. This construction of piers and abutments at 90 degrees to the structure centerline adds to the lengths of the spans.

Special Challenges

The traffic on I-15 is very heavy with commuter and normal interstate traffic — especially with commercial trucking — and has been considered one of Utah's most significant areas of traffic congestion. I-15 is the primary route for traffic into Idaho, as well as the connection to numerous communities north of Salt Lake City. These communities have long been popular with people working in Salt Lake City who wanted to live out of the big city. The construction schedule allowed very few and limited closures. Detour routes are limited, as well. The closure and detours were only allowed between 10 p.m. and 5 a.m. based upon high traffic data.

Running parallel to I-15 are separate railroad tracks serving heavy commercial rail traffic on the Union Pacific Railroad and Utah Transit Authority commuter rail traffic. These rail routes are not subject to traffic delays or interruption. Of course, detours are next to impossible for rail traffic. The rail issues were serious compared to auto and truck vehicle traffic on I-15. There were at least 35 trains per day, allowing intervals of only 10 to 15 minutes for construction crews to work between trains.

Clyde-Geneva had to coordinate with multiple entities, including other construction firms working on different, nearby projects. Through its strong working relationships with other organizations and companies, the contractor was able to adjust schedules and work to meet the demanding schedule and accomplish the required tasks on time.

The subsurface soils proved very unstable for structure support. This problem resulted in significant and unpredictable over-runs in structural piling. This created some problems with scheduling other related work dependent upon pile placement.

The most unpredictable problem was the weather. The winter of 2007-2008 was the worst in 16 years. The unusually harsh conditions created problems for soil compaction, concrete placement and asphalt paving beyond what was anticipated and thus impacted the original construction schedule. Despite weather conditions, Clyde-Geneva completed the project ahead of schedule, as did the other parkway contractors, which allowed the roadway to be opened nearly one month ahead of schedule.

The Clyde-Geneva team was led by Jeff Clyde, project principal and vice president, W.W. Clyde; Mike Bigsby, project manager, W.W. Clyde; Jim Golding, PE, Geneva Rock executive vice president; and Shane Albrecht, PE, deputy project manager. All of the employees on this complex project worked together to bring it to a timely, safe and successful completion. The efforts of all involved, including UDOT staff, are sincerely appreciated by the Clyde/Geneva team.

On Sept.13, 2008, after about 22 months of construction on Segment 3, the Legacy Parkway was officially opened to traffic. The dedication ceremony was led by Gov. Jon Huntsman Jr. riding a motorcycle, accompanied by other dignitaries on motorcycles and in antique cars. It was quite a celebration for those who had worked long and hard to make the Legacy Parkway a reality. In the first month following its opening, the parkway cut commute times and diverted more than 30 percent of traffic from the adjacent I-15.

Author Information
Freelance writer Bruce Higgins retired after a construction industry career spanning over 40 years. He lives in Farmington, NM.



Legacy Parkway Project Counts On HDPE Pipe

The Legacy Parkway project used more than 56,000 feet of Advanced Drainage System (ADS) high-density polyethylene (HDPE) pipe along with 400 feet of Hancor HDPE pipe for its stormwater drainage system. The HDPE corrugated pipe was selected based on structural and durability performance, competitive costs and its ability to withstand the corrosive nature of the soil.

Because the Legacy Parkway is close to the Great Salt Lake and near the Farmington Bay Waterfowl Management area about 10 miles north from Salt Lake City, there is a high level of environmental concern. It runs along marshlands and the Legacy Nature Preserve, which is home to migrating birds and ducks. The Preserve is a 2,200-plus-acre area on the southeastern shore of the Great Salt Lake that was established as environmental mitigation for the Legacy Parkway Project.

The impacts of excavation, building, construction traffic and materials were important considerations in this environmentally sensitive area. Construction crews are required to learn about environmental standards and pass a test before performing work on the project. Minimum intrusion into the sensitive areas and durability of materials were goals of the design team and contractors.

"HDPE was the pipe of choice because it stands up to corrosive environments like the high levels of salt and minerals naturally found in this area near the Great Salt Lake," said Larry Listello, Hancor sales representative for Utah. "The overriding concern was protecting the environment by using pipe that would last the longest time possible and would not have to be dug up and replaced in just a few years because the environment ate away at it."

The parkway project includes more than 10 miles of various sizes of HDPE pipe from 18- to 60-inch diameters. The majority of pipe is from ADS, made at a nearby plant. The project also called for a run of 54-inch-diameter pipe to meet the design flow rate. Available from Hancor, the 54-inch-diameter Blue Seal HDPE pipe was the exact diameter needed to carry the design flow and maintain appropriate cover without changing the road profile.

Watertight products were specified and selected from both manufacturers. ADS N-12 and Hancor Blue Seal pipe have an integral bell-and-spigot system and have been widely used in gravity flow storm sewer systems. They also fit the Environmental Protection Agency's Phase II best management practices for long-term service reliability.

Story provided by SCA Communications.