Montreal Rehabilitates Aging Water Mains Using CIPP

In 2015, the most populated and influential city in the Province of Quebec, the City of Montreal, continued its quest to lead the way in performing trenchless work on aging sewer and water main networks.

As a part of Montreal’s multi-year plan, city leaders announced that there would be a $257 million investment to update and maintain the City’s aging water infrastructure. An important part of the budget would be allocated to projects using trenchless technologies.

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The CIPP Solution

Montreal materialised its projections in spring 2015 by tendering approximately 28 km of water main rehabilitation using cured-in-place pipe (CIPP) lining. The project consisted of the rehabilitation of pipe diameters ranging from 6- to 12-in., the replacement of 163 fire hydrants, as well as 157 valve chambers throughout the 17 boroughs of the City.
Sanexen Environmental Services Inc. won the bid in February 2015 and, using its patented Aqua-Pipe product, accepted the challenge to complete the project before year’s end.

This water main rehabilitation project, on the secondary distribution system, was seen as a great challenge for multiple reasons. The 28 km of water mains were spread over 120 streets, each with its subtle challenges ,and was matched with the replacement of just under 800 lead service connections that needed to be replaced simultaneously.

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This undertaking had an impact on scheduling but Sanexen was confident in its planning and their technology to complete this part of the project accordingly. Throughout the last few years working with the City of Montreal, Sanexen successfully completed similar projects with the integration of lead service replacements in the job timeframe by using pulling and pipe ramming technologies, severely reducing the impact on the neighbourhoods and surrounding businesses and making for a true trenchless project. Many of the sites were in very sensitive areas such as the busy downtown core where traffic is quite heavy and historic old Montreal where tourism is essential to the city’s economy.

The most difficult jobsite was on Bridge Street, at the mouth of one the most travelled bridges connecting the downtown area to the residential south shore: Victoria Bridge. The 445-m section of water main is located at the center of the street and there needed to be replacements of many accessories such as hydrants and valve chambers. It was not possible to close the street at any time of the day so scheduling was essential from securing the site to enable the excavation crews to dig access pits to the positioning of lining equipment over top. The water main temporary bypass was installed with very few ostructions as traffic was passing by.

The rest of the Aqua-Pipe operations, such as cleaning, plugging and reinstatement of service connections were completed by working around the clock and by constant modifications to signage in order to accommodate changing traffic flow. The Aqua-Pipe team lined the water main in only two insertions, each more than 200 m in length. A tight schedule was the key to this worksite as every team was closely followed by the next to assure no downtime. The whole worksite lasted 22 days from bypass installation to restoration and was a complete success in the eyes of the city of Montreal.

Aqua-Pipe Shines

Throughout a project of this magnitude, Aqua-Pipe had the opportunity to show on many occasions its adaptability to various situations.

Some of the pipes that were lined were installed in the early 1900s and the plans given by the City were not always accurate. It is when you face situations like unmarked bends and services, abandoned valves and variations in the pipe diameter that a good versatile product like Aqua-Pipe shows its value. Many non-protruding service connections were found in residential areas of the eastern part of the City, with redesigned plugs and great team of operators, they were drilled with an excellent rate of success. Furthermore, the entire crew demonstrated poise and creativity, when facing unknowns, quickly finding solutions that were cost effective for the city and in line with the schedule.

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This water main rehabilitation project executed in Montreal was a success from different standpoints: cost and time efficiency. The amount of water saved from the now lined 28 km, over the past eight months of work is quite impressive. The City of Montreal is convinced that it found, through rehabilitation, the way to upgrade and durably sustain its water main network. As confirmation, the City recently confirmed its plans to continue to invest equivalent amounts of capital over the next three years in their water and sewer infrastructure.

Due to the complexities of managing such a large territory, the City of Montreal continues to prioritize the use of rehabilitation and trenchless technologies before considering traditional infrastructure dig and replace. The often priceless or intangible cost benefit to the residents and businesses is important to the City is shown through its choice of technologies. The new tradition has become rehabilitation.

Didier Girard, ing., is a project manager for Sanexen Environmental Services Inc., Aqua-Pipe division and Michael Davison, ing., is Aqua-Pipe product director.