Conceived in 1812 and amalgamated with constituent neighbouring municipalities in 2001, Hamilton is now a vibrant, growing city in the province. In 2002, a new Asset Management section was formed within the Public Works Department with the mandate to strategically manage existing road, sewer, water and facility assets in a financially constraint environment with many competing infrastructure needs.
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Asset Management for municipal infrastructure has been, and still is, an evolving practice around the world. While Hamilton Public Works has been at the forefront of asset management, it continues to evolve bringing more asset classes into the asset management practice and incorporating factors such as growth, climate change, legislation, communication strategies and community engagement into its decision models and management frameworks.
Asset Management and Trenchless
In its early stages, the Asset Management section recognised the immense benefits of trenchless technologies for the proactive and cost-effective inspection and rehabilitation of existing infrastructure. Trenchless industry, technology advancement and use continue to be an integral part in Hamilton’s infrastructure management framework.
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The industry has always perceived Hamilton as an advocate for trenchless technologies and innovative spirit. We are involved, sharing ideas, providing support and facilitating an environment that encourages growth and innovation. Hamilton helps maintain the momentum in the trenchless front by supporting pilot projects, being involved in academic research initiatives and undertaking major rehabilitation programs.
Currently, the Asset Management section falls under the Engineering Services Division in Hamilton’s Public Works Department. The group is responsible for the management existing Right of Way (ROW) infrastructure (road, sewer, water and bridges), corporate facilities and parks, and development, coordination and delivery of capital works scope and budget. While Asset Management is known as a section, the concept of asset management is now implemented within water distribution and wastewater collection capital, maintenance and operations.
Asset Management looks far into the future and aligns short-term plans to a long-term sustainable goal. With many competing needs and limited resources, the emphasis is on risk/service needs and projections rather than strictly technical needs.
Inspection and rehabilitation of sewer and water linear assets is performed and prioritised based on the principle of risk. In its simplest form, risk can be defined by the product of the consequence of catastrophic failure and the probability of failure for every single asset. Consequence of failure has been determined by how an asset rates against environmental, economic, social and operational parameters. Various methods and levels of condition assessment have determined probability of failure.
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A desktop-based condition assessment that looks at asset information readily available, such as age and material, can provide an acceptable high-level condition assessment for low “consequence of failure” assets. In contrast, highly rated “consequence of failure” assets require a more deterministic approach and the level of inspection can become highly specialised and costly.
The minor water distribution system poses low risk it can be managed by high-level condition assessment, opportunistic and proactive capital coordination, and by regular operations and maintenance forces on a daily basis. The physical inspection of high-risk water distribution assets varies in effort and may include anywhere from simple soil sampling to man entry and daylighting.
Hamilton has inspected most of the critical trunk mains in its 2,060-km total distribution system, the technologies employed have ranged from acoustic leak detection and monitoring to electromagnetic pipe wall thickness and wire break detection in prestressed concrete pipes. Opportunistic sampling, taking a physical sample of the main for observation and laboratory testing and a sample of the surrounding soil, is another method used on mid-to-high risk assets during repair excavations.
The City is currently considering long-term live monitoring on crucial high-risk water assets.
Inspection of major trunk mains is a challenging task, as it requires various levels of expertise and stakeholder coordination and involvement. Inspection methodology and technology selection, cost, hydraulic system impacts, state of existing valves and valve chambers, dewatering, disinfection, recharge, critical customers and coordination with other conflicting projects are some of the items and challenges for consideration. The added benefits of such projects, other than determining condition, is the knowledge and expertise gained by internal forces increasing the confidence and preparedness in the event of a major failure.
Subsequently, the 2,900-km linear sewer network is managed in the same manner. The City has inspected approximately 90 percent of the water and wastewater collection system by various methods and technologies.
Inspection ranges from zoom camera inspection, traditional CCTV inspection, to more complex inspection types and technologies. Pipewall cleaning and visual man entry remains the most reliable inspection for large diameter sewers. Hamilton has employed technologies such as LiDAR (light detection and ranging), submersible ROVs (remotely operated vehicles), and PPR (pipe penetrating radar) similar to GPR (ground penetrating radar) technology but from within the pipe to detect voids behind the pipe wall.
Since 1992, Hamilton has used cured-in-place pipe (CIPP) lining and to-date, 350 km of sewer have been renewed using the technology at a total cost of $87 milion. This equates to an average cost of $250/lin.m. The estimated savings realised by the CIPP rehabilitation program, not including social cost-savings, is estimated to more than $180 million when compared to traditional open-cut replacement. While the design life of these products is 50 years, it is projected that the lined pipes will continue to perform past the design life to an average of 60 to 80 years.
CIPP lining is also employed on water main but at a smaller scale. Since 2003, the City has successfully rehabilitated 52 km at a total cost of $40 million.
Water main CIPP lining involves temporary bypass, replacement of all valves and hydrants and trench restoration. Projects are selected as an alternative to watermain replacement to combat structural condition and water quality issues. Hamilton has determined that CIPP lining is a better alternative to Cement mortar lining because the up-front costs pf mobilization and bypass are almost identical; additionally CIPP offers a fully structural trenchless solution.
Harry Krinas is acting senior project manager, Asset Management, for the City of Hamilton, Ontario.