PROJECT DETAILS

/ CONTEXT Delsan AIM entered into a subcontract agreement with the consortium, KPH Turcot, to dismantle a railway tunnel as part of the Turcot Interchange Reconstruction, which is a major $3.7 billion civil infrastructure project being undertaken in Montreal, Quebec.

/ DISMANTLEMENT The dismantlement occurred within the right-of-way of an important Canadian National (CN) transportation corridor having four (4) railway tracks that remained in use during the course of the project. The work, which was performed in accordance with detailed engineering procedures, had to be closely coordinated with CN operations in order to protect existing infrastructures, while maintaining train traffic and ensuring the safety of all personnel involved. Another important facet of the project required the abatement of asbestos-containing fire-proofing material, which was found to be present on the ceiling of the main tunnel.

/ CHALLENGE Prior to the commencement of the project, the tunnel, which was located underneath Boulevard Ste-Anne-de-Bellevue, was exposed to facilitate the removal operations. The original structure consisted of a 30 feet high by 74 feet wide, three-sided reinforced concrete box culvert supported on concrete footings with an overall length of 333 feet. The entrances were constructed of concrete retaining walls. A 54 feet extension to the original construction on the east side had a different structure with a roof that consisted of a series of reinforced concrete box girders that spanned the tracks.

/ The extension was dismantled in sections by saw-cutting and removing the box girders along with the associated slab, which weighed 85,000 pounds each, as well as sections of the retaining walls using a 500-ton mobile crane, with the heaviest lift being 114,000 pounds. Where there was sufficient clearance from adjacent railway tracks, Delsan AIM utilized excavators with hydraulic hammers to systematically demolish the remaining retaining walls.

/ The original structure, on the other hand, was dismantled in nine (9) sections, each weighing 1,100 tons, by means of a gantry crane that was positioned over the tunnel using self-propelled modular transporters (SPMTs). A temporary level crossing was constructed so that the gantry crane could be positioned to straddle the structure and transport the sections to a laydown area south of the tunnel for further processing.

/ SAFETY FIRST The fire-proofing was subsequently removed at this location in accordance with high-risk asbestos abatement procedures using an excavator equipped with a scarifier. Upon final clearance of the decontamination work, each section was demolished using large excavators and the debris shipped off site for recycling.