British Columbia: Coquitlam Capital Works: B&B Relines Deep Culverts in Coquitlam
Use of new technology benefits local residents. The City of Coquitlam and B&B Contracting Ltd. put innovative new technology to work for the benefit of local residents in a recent Chineside Neighbourhood culvert replacement upgrade and repair project. Coquitlam and B&B successfully completed the culvert project on time and at dramatically lower costs than would have resulted using more traditional methods. Applying its new Ultraliner system, B&B completed the project in record time, and the approach ensured the best options for protecting a fisheries sensitive watercourse in the area.
Author(s): John Kupskay, P. Eng.
Publication Date: 11/27/2001
IP Owner(s): Paragon Engineering Ltd.
Languages Available In: English
The Full Document:
The Chineside Neighborhood in the City of Coquitlam is in the process of undergoing a Neighborhood Improvement Program. Each year, the City, which is approximately 50 kilometres east of Vancouver, undertakes a complete overhaul of a residential neighborhood, including offering residents a chance to upgrade their streets on a cost shared basis. The Neighborhood Improvement project for 2001 involved the upgrading and replacement of underground infrastructure in advance of repaving scheduled to be done in the summer of 2001. City Project Manager Dave Wone, AScT, developed a schedule to have underground utilities in the neighborhood evaluated, upgraded or replaced before paving. Separate programs for replacement of waterlines, sanitary sewers, and sanitary services between the main and property lines were completed in early 2001.
Two particular storm sewer lines concerned Wone during planning of his upgrading program. Caledonia Creek, the major watercourse and drainage artery for the Chineside area, contained two deep 600 millimeter diameter corrugated metal pipe (CMP) culverts, one under Oneida Drive and the second under Corona Crescent. The Oneida CMP culvert was 27 metres long and between 4.5 and 5.5 metres deep at a 13.95 per cent grade. The Corona CMP/Concrete culvert was 90 metres long and between 2.5 and 6.0 metres deep at 25.60 per cent grade. Both culverts passed under existing paved roadways in fully developed areas. Both had shown signs of extensive deterioration.
Wone, who was familiar with the application of trenchless technologies to pipe replacement, approached B&B with a view to investigate a possibility of relining the culverts rather than reconstructing. Existing pipe condition B&B's Trenchless Division Manager Dennis Connolly AScT conducted a detailed investigation to confirm the condition of the existing culverts. A&A Testing Services Ltd. (a division of B&B Contracting Ltd.) visually inspected the sewer lines using closed circuit television (CCTV) equipment. The result of this investigation confirmed the extent of deterioration and the extent of missing sections of pipe invert.
Sections of the bottom of the pipe were missing for lengths up to 300 to 450 millimeters long at three or four locations throughout both of the pipes. There was also a short section of the CMP in the Oneida Drive culvert where the top of the pipe had settled and was approaching 10 per cent loss in ovality. These particular conditions made it apparent that the culverts needed replacement or rehabilitation before paving operations were completed. The existing CMP culverts were badly deteriorated. The challenge in replacement of the pipes was that the pipes were deep and at steep slope through a fisheries sensitive watercourse.
The city had investigated other options for replacement of the pipes and had confirmed that replacement using the Ultraliner system was not only their most economical alternative, but also the alternative with the greatest likelihood of a successful installation under such difficult conditions. Ultimately, Ultraliner Fold and Form PVC liner was selected for use because it could provide greater quality assurance and a much lower risk of installation failure under such difficult conditions.
Ultraliner is a "fold and form" trenchless pipe reconstruction process that is installed into an existing pipe in a heated and softened folded shape and formed against the host pipe resulting in a stand alone structural pipe after processing. The liner is folded into a collapsed kidney shape at the time of manufacture and is delivered to the job site in rolls. In preparation for installation, the folded pipe is heated until it?s flexible, then using a system of winches and cables and a specially designed pulling head is pulled off the spool into the old pipe. Steam, with or without a specially designed rounding device, is blown into the pipe to open the folded liner and push it to a tight fit against the old pipe. After rounding, the newly installed liner is cooled under pressure. The result is, in effect, a new pipe within the old pipe.
The Ultraliner product is supplied to B&B locally by Pipeline Supply International Inc., under exclusive territorial license from Ultraliner, Inc. of Oxford, Alabama. B&B retained the services of Paragon Engineering Ltd. of Maple Ridge, BC to assist them in designing the pipe liners. Paragon, with the assistance of Ultraliner Inc. technical personnel calculated the required Fold and Form UltraLiner design thickness. Due to the deteriorated condition of the host pipe, industry standard design methodologies could easily suggest the need for a DR 35 pipe liner. As 600 mm diameter Ultraliner was only available at DR 48, Paragon and Ultraliner analyzed the structural design of the liner taking into consideration enhanced effects due to the apparent increase in strength that would result as the Ultraliner formed around the corrugations of the existing CMP culvert. The results of this analysis confirmed that the DR 48 liner should be adequate for the installation.
It is believed that the existing soil tunnel surrounding the pipe is stable and that the active soil loadings on the pipe are minimal, further contributing to acceptance of the DR 48 liner. The City also reviewed the history related to construction of the CMP culvert and believed that the deformation noted was most likely caused by the addition of a length to the end of culvert at the time of embankment widening. As a result, installation of the liner was viewed as a maintenance installation to solve the problems of deteriorated invert. The city accepted the recommendations of Paragon and B&B and agreed to share responsibility by accepting the DR 48 liner.
This was the largest diameter and most challenging liner installed by B&B to date, not to mention that the liner to be used was the maximum diameter produced by Ultraliner. To ensure success during liner installation, B&B requested that Lee Trotter, one of Ultraliner Inc.'s field service representatives, be present during the installation in the event that problems occurred.
Immediately before construction, the host line was thoroughly cleaned by B&B personnel followed by reinspection with CCTV equipment. The installation proved to be a challenge because the bulky and heavy liner had to be inserted from road level, down a five meter steep bank, over a series of steel rollers before entering the deteriorated CMP pipe. Once the liner was pulled through the existing CMP pipe, the ends were sealed and the pipe was reheated with steam. After warming to allow the liner to soften, low-pressure air was introduced to reform the Ultraliner to the shape of the host CMP pipe. The installation was completed in a matter of hours for each of the two lines. The post installation video showed a tight fitting liner that satisfactorily rehabilitated the existing culverts.
The total cost of the project was $81,000 dollars for a total of 117 metres of liner installed. Other relining methods or open cut were estimated to cost more and to have greater risk and to create greater disruption.
After completion of the project, Coquitlam's Wone stated that the city was extremely pleased with the operation and looks forward to more installations of this kind and working with B&B Contracting Ltd. on future relining projects. The city is to be commended for its approach and acceptance of the innovative use of the Ultraliner product for culvert rehabilitation. City taxpayers should also be happy with the significant cost savings (+/- $200,000) achieved through the use of innovative technology.