Published on March 1st, 2013 | by UC&D Magazine0
Most Challenging Aspect of FrontRunner South: Jordan Narrows
Clear and grub: 307 acres (nearly 450 football fields)
Pipeline placed: 106,505 LF
Dirt moved: 1,719,762 CY
Concrete Ties: 118,272
Rail: 53 Miles (10,500 tons)
Walls: 475,065 SF
Sub ballast: 391,073 tons
Ballasts: 515,845 tons
GeoFoam: 1,271 CY
Fence: 182,684 LF
Total Man Hours: 2,182,237
When engineers and contractors working on the FrontRunner South first started their initial approach on the job, they targeted the Jordan Narrows – an approximate 4.5 mile stretch west of the point-of-the-mountain – as the most challenging section over the more than 45-mile corridor from Salt Lake City to Provo.
“It was easily the most difficult part of FrontRunner South,” said Clayton Gilliland, Project Manager for Stacy and Witbeck in Salt Lake City, part of the general contractor joint-venture team along with Herzog of Long Beach, Calif. “We had to phase construction over three seasons because of interaction with canal companies and Union Pacific Railroad (UPRR), plus it had an extremely limited access. We knew it would be a difficult area, so we focused design to get that area rolling initially. It was one of the top five critical paths on the job.”
“It was a very difficult section for the entire team,” said Jon Cluff, Project Manager for Utah Transit Authority (UTA). “They had to contend with the Jordan River and various canal companies, and were limited to working during winter months. It was a tremendous accomplishment from everyone involved with the project.
One of the innovations in the Jordan Narrows was eliminating several bridge structures through the installation of steel multi-plate and box culverts, which were more economical and efficient to construct. The team also eliminated bridge spans over roadways by constructing MSE wall abutments, which reduced the bridge footprint and roadway impacts. Constructed from June 2008 to December 2012, the new line runs from UTA’s Central Hub in Salt Lake City to the new Provo station, and traverses more than 45 miles of corridor running through 14 cities. Other challenges including UPRR track relocations, the construction of more than 60 structures consisting of multi-span and single-span bridges, a flyover of UTA over UPRR tracks, soil nail retaining walls, box culverts, 380,000 SF of MSE retaining walls, 40,000 SF of post-and-panel retaining walls, and over 50 existing at-grade crossings. The construction also built eight station platforms and four park-and-ride lots.
“From a design standpoint just the amount of coordination it took with all the different entities involved was remarkable,” said Matt Wildauer, Project Manager for lead designer Parsons Transportation Group (PTG) of Salt Lake. “It required a tremendous amount of coordination between ourselves, the program manager (Parsons Brinckerhoff of Murray), the contractor and UTA officials and that’s one of the reasons the project was able to be completed ahead of schedule. It was a great team effort.”
The fact that PTG and Stacy-Witbeck /Herzog had worked together on FrontRunner North also proved valuable in that they already had established some best practice policies and solid relationships. FrontRunner North was an infinitely easier project, so the lessons learned on that job really aided the design and construction process on FrontRunner South.
“If FrontRunner South had been done first, it would have been much more difficult and required a longer schedule,” surmised Wildauer.
“We had worked together previously and we got on board at about 30 percent design and were able to help with bridge value engineering and standardizing bridge design to include precast box girders where possible, and just have a more economical bridge structure in applications where it would work,” said Gilliland.
The flyover section between 9400 South and 10000 South in Sandy was another critical aspect of the project. The tracks run on the east side of UPRR’s line and then cross over at this section to the west side of UPRR’s line. The flyover structure includes a special lightweight aggregate called ‘Gail’s Gold’ from Fillmore on the approaches to mitigate settlement and avoid expensive ground improvements. The aggregate weighs less than a ton per yard, compared to regular aggregate with is 1.6 tons per yard.
Environmental sensitivity was also displayed throughout the corridor. In several locations the design team was able to reduce the track footprint to remain within the right-of-way and avoid disturbance of culturally or environmentally sensitive sites. In Draper, north of Bangerter Highway, a wall was constructed at minimum offset to UTA track, since encroachment on property outside the right-of-way was not allowed. A minimal cut into the embankment east of the Thanksgiving Point Golf Course was also designed in lieu of an approximately 4,000 ft long soil nail retaining wall that was part of the original design.
“We couldn’t be happier with the end result,” said Cluff.
FrontRunner South – Salt Lake City to Provo
Cost: $850 Million
Owner: Utah Transit Authority
GC: Commuter Rail Constructors (Stacy and Witbeck/Herzog JV)
Design: Parsons Transportation Group (prime)
Design Subconsultants: HDR Engineering; Horrocks Engineers; Terracon; Psomas; McNeil Group; CRSA; InterPlan; Riley Transportation; Hegerhorst Power Engineering
Program Management: Parsons Brinckerhoff (prime); Cordova Design Inc.
Key Subs: Ralph L. Wadsworth Construction; Rocky Mountain Signal Services;
Ralph Smith Trucking; Brinkerhoff Excavation; Geneva Rock; Construction Materials Company; Innovative Excavation