- ENGINEERING INFO
- CASE STUDIES
For the past several years crews with the City of Helena have had to make multiple repairs on a critical transmission water line located on Airport Road, parallel to the Helena, MT Regional Airport. The existing 20" diameter steel pipeline was installed in 1963. The line was located in a congested utility corridor near many other services, most notably a gas transmission line. As a result, conventional dig and replace was not a desirable solution.
The City evaluated several options including pipe bursting, sliplining with HDPE pipe, and relining the existing pipe. Due to cost, the need to maximize flow capacity, and a desire for standard mechanical connections, the City determined that sliplining with Fusible PVC® pipe was the best solution for their project. The City completed an early conceptual design in 2007. The final detailed design was finished in mid-2009 when the budget was approved and funding became more readily available via the American Recovery and Reinvestment Act (ARRA).
Robert Gibb & Sons commenced construction in late September 2009. The design provided flexibility to the contractor in terms of pit locations, pull lengths and equipment. There were a few valve locations and one angled section that required excavation. The contractor utilized the angled section located approximately 1,900 LF from the west end of the line as the primary pull pit from both directions. Using a HammerHead® static bursting machine the contractor was able to pull long strings of fused pipe into the existing steel pipe. Two pulls of 1,900 LF and 3,200 LF were completed with intermediate pits required only for rod retrieval and line connections. Grouting and pressure testing were completed in November 2009.
Rick Vonhagen, Municipal Foreman with Robert Gibb & Sons stated: "Fusible PVC® pipe worked very well for us on this job. Underground Solutions did a great job supporting us in the field throughout the entire job. Thank you so much for all your help and we look forward to working with you on the next project."