- ENGINEERING INFO
- CASE STUDIES
Eagle P3 is part of RTD’s 2004 voter-approved FasTracks plan to expand mass transit across the Denver metro region. The $2.2 billion project is comprised of the East Rail and Gold Lines, the first segment of the Northwest Rail Line to Westminster, procurement of 54 commuter rail cars, and a commuter rail maintenance facility. The project is scheduled for completion in 2016. P3, or public-private partnership, is an innovative project financing and delivery method in which a public entity partners with the private sector. The private sector team invests its own money and assumes much of the risk on the project. This approach allows the public entity to spread out large upfront costs while preserving public cash. Below is a summary of the major lines on the project:
Northwest Rail Line: A 6.2-mile first segment running between Union Station and Westminster Station near 71st Avenue and Lowell Boulevard. This will be called the B-Line.
East Rail Line: A 23-mile electric commuter rail corridor between Denver’s Union Station and Denver International Airport that will pass through east Denver and Aurora. The line will include five intermediate stations and be named the A-Line.
Gold Line: An 11.2-mile electric commuter rail corridor between Union Station and Ward Road in Wheat Ridge that will pass through northwest Denver, Adams County, and Arvada. The line will include eight stations and be named the G- Line.
Fluor/HDR Global Design Consultants, LLC is the lead designer within the Denver Transit Partners group, the concessionaire selected to design, build, finance, operate, and maintain the project.
|Pipeline Details and Project Summary|
|Project:||Northwest Rail Electrified Segment 2|
|Location:||Westminster, CO (Pecos & 64th Ave)|
|Length & Pipe Size:||439 LF 20-inch DR18 Blue Fusible PVC® Pipe|
|Pressure Test||150 psi for 2 hours|
|Installation:||Jack-and-Bore Slipline Pre-Insulated Carrier Pipe|
|Owner:||Crestview Water District|
Adding a new mass transit line through the heart of a city over 150 years old requires thousands of existing utilities to be relocated. Some of those existing utilities are potable water lines. In addition, construction of a mass transit rail system also requires that potable water lines be cased inside steel casing pipe when crossing the rail alignment. According to Denver Water Company’s standard specifications for potable water lines inside a steel casing, a restrained pipe system such as Fusible PVC® pipe must be used as the carrier pipe. Most of the cities surrounding Denver where the light-rail system is being installed recognize Denver Water’s specifications.
Fusible PVC® pipe is a preferred solution in this application for several reasons: It provides a fully-restrained pipe system with a uniform outside diameter, with no bells, restraint harnesses, or couplings extending beyond the diameter of the pipe barrel. The smaller OD of the restrained pipe system translates into a smaller steel casing pipe which is less expensive to purchase and jack into place.
One particular crossing on the Northwest Rail Electrified Segment 2 Project passing through the Crestview Water District required a 20-inch potable water line to be hung under the Pecos Street overpass above Clear Creek. The engineering team adhered to Denver Water’s preference for Fusible PVC® pipe as the carrier pipe inside a steel casing, but since this was an aerial crossing there were several additional design considerations. Pre-applied insulation was specified to protect the carrier pipe from the highly variable temperatures the pipe would experience in an aerial crossing.
Canadian company, Urecon Pre-Insulated Pipe Systems, was selected to supply insulation for the Fusible PVC® carrier pipe. Thirty-six inches was left uninsulated on the end of each pipe length so that the pipe could be placed in the on-site McElroy fusion machine for fusing operations. Insulation in the areas of the fused joints was applied following fusion, with two semi-circular pieces strapped into place using stainless steel bands. In addition, stainless steel casing spacers were used to prevent damage to the insulation while pulling the pipe into the steel casing.
Though the insulation was believed to be highly effective at preventing excessive expansion and contraction, the engineering team decided to use the additional precaution of specifying expansion joints on both ends of the aerial crossing.
Colorado road constructor, Ames Construction, was awarded construction of the Northwest Rail Electrified Segment 2 Project. Site conditions proved challenging for fusion layout so a fuse-and-pull installation approach was required. Fuse-and-pull installation works extremely well in slipline applications since there is no risk of the annular space closing on the new pipe during installation and the operation does not take any longer than fusing the entire string on-grade and pulling it into place.
Larry Pagel of Ames Construction commented: “This was our first experience with Fusible PVC® pipe. The insulation was a challenge at first, but with the help of Underground Solutions’ fusion technician we figured it out. I think it’s a great product and we were all impressed with how easy it was to install.”