by Saeed Mirza, FCAE, Professor Emeritus of Civil Engineering, McGill University & Past President, Canadian Society for Civil Engineering. A version of this article was published in the National Post on January 18, 2014.
Minister Lebel and the Government of Canada have correctly pledged to construct an aesthetically pleasing new Champlain Bridge by 2018. The structure will have a service life of at least 100 years, assuming routine maintenance. In view of the structural needs, environment, economy and aesthetics, two cable-stayed bridges – one from Montreal to Ile Notre Dame and the second from Ile Notre Dame to the South Shore, clearing the St. Lawrence Seaway would easily achieve the above goals, and would be much less costly than any other type of bridge.
The Champlain Bridge, opened in 1962, was originally designed by engineer Hugh Pratley entirely in steel; however, the Progressive Conservative Government of the day intervened and divided the project into smaller contracts. They left the part over the St. Lawrence Seaway in steel as originally designed, but adopted a cheaper French design version as an alternative for the rest of the bridge. This consisted of seven prestressed concrete girders with extended top flanges, in-filled with cast-in-place concrete and post-tensioned together to form an integral unit with seven girders and a continuous top flange, along with the diaphragms for improved load distribution between the girders. Unfortunately, this alternative did not permit easy, routine maintenance, and it was very difficult and almost impossible to replace any element, such as a girder. Also, because of the lack of drainage on the superstructure, which was not considered in the original design, the exterior girders got quite severely damaged because of the use of de-icing salt for traction during winters. Initially, it was planned to use ashes for traction during winters as had been the practice in Quebec at that time. Under normal circumstances, it would have been possible to stop the traffic briefly in a couple of lanes over a weekend, and replace the girder. However, the unusual design completely eliminated this option and these girders had to be strengthened at an exorbitant cost because of the design adopted due to the Government intervention.
The current Champlain Bridge was designed with a specified concrete strength, and it was found to be adequate; however, its permeability (the ease with which salt solutions or any other fluids find ingress into the concrete) was not a part of the original specifications and was not checked. Because of poor drainage, the salt solution caused extensive corrosion damage to the edge girders, girder ends, bearings, pier caps and piers, requiring very expensive rehabilitation. This has led to large repair and rehabilitation expenditures, many times the original cost of the Champlain Bridge which was about $30 million. The cost of the current super-beam repair alone is estimated to be about $3 to $4 million. It is therefore imperative that unlike the present practice of designing for the lowest construction cost without taking into consideration future maintenance and any rehabilitation, when needed, the engineers must design any infrastructure facility, not just for the initial construction costs, but also for its maintenance and any needed changes, and rehabilitation over its entire service life, and provide a maintenance plan to the owner, as is the current practice with automobile dealers. The engineer would also be wise to plan a mid-life structural integrity audit, as many of us have with our doctors for a complete check-up when we reach the age of 45-50 years.
In planning the new structure, we must not repeat the past errors committed with the design, construction and maintenance of the present Champlain Bridge, along with the unwise government interventions. The announced service life of 100 years would require a design life of about 150 years for the ultimate limit state (involving minimum strength and durability of the system). Tools are presently available to ensure that a well-designed concrete bridge, constructed using excellent quality control and proper inspection and maintenance, will last for about 150 years. Properly installed barriers or jackets of fibre-reinforced polymers, which can inhibit or at least slow down considerably the ingress of the deleterious substances into the concrete, can easily increase this service life to approximately 200 years.
Is the user paying for the full cost of maintenance, repair and rehabilitation of the Champlain Bridge? Certainly not directly. The Government of Canada pays for these activities from the taxes paid by the Canadian tax-payers. Therefore, it is still paid by the user but from a different pocket. In fact, the infrastructure operations are subsidized considerably by the different levels of government; however, the fact remains that finally it is the user that pays for the upkeep and operations of infrastructure facilities. Presently, depreciation of infrastructure assets is not considered in the costs to the user, with the result that once the infrastructure asset reaches the end of its useful life, different levels of government are scrambling to find funding source(s) to pay for the replacement. How will the total costs of owning, maintaining, operating and demolition and disposal at the end of the service life be paid? Presently, the user pays for it directly through user fees, or indirectly through the government. The logical thing is to accept that the user must pay for all of the costs involved – technical, environmental, economic, social and any other costs. The governments would have to decide subsidizing the users who are unable to pay part of the total cost. This includes tolls on highways and bridges. The Federal Government should also consider relinquishing more tax fields to the municipalities; the municipalities enjoy only 8% of the tax dollar in Canada, while they own and are responsible for more than 50% of all infrastructure assets in Canada.
At one time, there were tolls on the Champlain and Jacques bridges and some Quebec highways, such as the Laurentian and the Eastern Autoroutes. There was a toll on the Victoria Bridge when the current truss form structure was put in operation in 1900. Many financially constrained governments around the world have successfully resorted to Public-Private-Partnerships, (PPPs orP3s), under which the private entrepreneur finances, designs, builds and operates the system for an agreed period of time, during which the cost of financing, design, construction, maintenance, etc., are recovered by the entrepreneur. These costs are paid principally by the user through tolls or user fees. The Confederation Bridge between Prince Edward Island and New Brunswick is an example of a PPP project. Whatever the mode of financing, finally it the user who pays for all of the expenditures involved. Therefore, we must keep politics out, and bite the bullet and accept the tolls, which along with other funds, will enable the bridge to be maintained well to serve our grand-children and their grand-children for the next 100 years and more.
