The T-shaped piles under the access ramps at the St Peters Interchange, Montreal, Canada are safely

The T-shaped piles under the access ramps at the St Peters Interchange, Montreal, Canada are safely repaired with the help of Fraco mast climbers.

Canadian mastclimber manufacturer, Fraco has been using its expertise to help repair the supporting piles on some of Canada's roads. The workplatforms have provided both access and a comfortable and safe environment for the workforce carrying out repairs.

The St-Peter Interchange is located in the south-west of Montreal at the junction of Route 138 to Highway A-20. Repair work on the five piles located under the access ramps has been ongoing since October 2009

In order to ensure safe works, general contractor GTS (Les Grands Travaux SOTER Inc.) approached Fraco for mast climbers. Ten units were moved to the project location, some mounted on free standing bases, others on ground bases. Installation and dismantling was carried out by Fraco technicians.

The repair work involved several phases: identification of damage areas; concrete chipping; cleaning; steel insertion and rebar reinforcement; formworks installation and concrete pouring. Telescopic booms could have been used for operations such as the identification of damage areas, but for other work GTS needed a stable and flexible access system that could support the weight of tools, hammers, workers and all materials needed to repair each pile. Because of their high load capacity and their large working area, Fraco's ACT-8 mastclimbers were chosen

The size of the piles depends on their positioning under the ramps and their height varies between 20 and 28 m. Generally, the piles have a T-shape. Each pile needed two work platforms, positioned on the larger faces of the pile. The installation of short gateways between each mast climber allowed access to lateral faces. Other access systems were also necessary in the upper parts of each pile.

In order to guarantee the bearing capacity of piles, GTS followed an operation procedure prepared by MTQ (Ministry of Transport of Quebec). That procedure stipulated that each pile must be divided into four sections of work, each to be completed before the start of the next one. Thus, the repair works always started by lateral sections of the first quarter (section 1) of each pile (phase 1). Once the concrete was poured and lateral sections completed, GTS was repairing the axial sections located on each face of the pile in three steps (phase 2). The T-shape part represented the last section to be repaired. To do so, that part was divided into two sub-sections and the workers have repaired the diametrically opposed faces (phase 3 and 4) in one step. (See diagram)

Gerald Harnois, foreman at GTS, said that Fraco's platforms brought a dimension of comfort and safety, "Boom lifts have made the works difficult to complete because of their lack of stability. Our employees were expecting the same effect with the Fraco, but they realised the difference after few minutes of utilisation. These machines have really transformed their work environment."

The concrete chipping phase requires hammers that can destabilise the boom lifts and other scaffolding, which is often used for repairing concrete piles. The length and scope of Fraco mastclimbers allows minimum movement around the pile.

Based on the success of the St Peter Interchange, the Canadian-based company was given the mandate to supply the same equipment for a similar project at the Turcot Interchange in Montreal.

Located 5 km southwest of downtown of Montreal, the Turcot Interchange connects Highways A-20, A-15 and route 720. It provides access to Champlain Bridge, to downtown Montreal and to the west and northwest areas of the island of Montreal. The interchange came into operation in 1967 and a redevelopment plan is expected during the next 10 years.

Pending the beginning of the redevelopment works, general contractor DJL was commissioned by the MTQ to maintain and repair the piles of few ramps that require immediate action. After visiting the St-Peter Interchange jobsite, DJL representatives chose to use Fraco mast climbing work platforms for the repair work. At the beginning of June 2010 Fraco installed six units, which are now being, used under three ramps.

Since the MTQ redevelopment plan includes the construction of new roads under the present access ramps, Fraco expects that the maintenance and repair of piles will continue over the coming years.

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