To connect the urban centers north and south of Salt Lake City, the Utah Transit Authority purchased 175 miles of railroad corridors between Payson and Brigham City in 2002 to construct, among other facilities, a commuter rail system known as “FrontRunner.” The alignment of the commuter rail extends 44 miles, contains 38.15 miles of exclusive right-of-way, shares 5.87 miles of track with Union Pacific Railroad (UPRR) and has 43 at-grade crossings and a 2,043-ft bridge over the UPRR Ogden rail yard.
By November 2006, construction of FrontRunner was 50% complete. Concrete storm drains run parallel to the existing railroad and I-15 freeway corridor. With the commuter rail being constructed between the existing UPRR freight tracks and the I-15 freeway, much of the parallel storm drain had to be relocated. Through field inspections of the reinforced concrete pipe storm drain, however, it was verified that the reinforced concrete pipe was functioning as designed and many runs would not need to be replaced or relocated.
In some sections where track would be constructed on top of the pipe for long distances, relocation of the drain was considered a better long-term option. The contractor salvaged as much concrete pipe as possible for reuse by the Davis County Public Works Department. The pipe was fitted with new gaskets and reused in stream channels throughout the county.
The salvaged reinforced concrete pipe was manufactured in 1980 to a Class III standard design. Railroad designers typically require that Class V reinforced concrete pipe be installed to meet the E-80 loading requirements under railroads tracks. To verify the actual class of the salvaged pipe, design load testing of the salvaged 54-in.-diam. pipe found that the ultimate strength of the pipe was 125,000 lb. This was a few percentage points under a Class V pipe. It is estimated that the pipe exceeded its original design requirements by 73%.
This strength of the concrete far exceeded the typical design requirement of 4,000 psi for pipe that conforms to ASTM C76. The concrete pipe, with a salvage value of approximately $175,000, was immediately available for use demonstrating an aspect of life-cycle cost analysis (LCCA) that is often overlooked.
Life-cycle cost analysis for concrete pipe systems is covered in ASTM C-1131. The procedures include provisions for residual or salvage value, which is the remaining value of the structure at the end of its design life. If an LCCA was applied to the FrontRunner project (with a 25-year design life), the salvaged concrete pipe would increase even further in value, because the cost of new pipe would have increased since 1980.
The FrontRunner project includes over 6,500 ft of newly produced reinforced concrete pipe and associated cleanouts and junction boxes. The pipe was specified as Class V if it were to be under the rail line or under heavy construction loads. Class III pipe was specified in areas of more typical loading and construction.
