CONCRETE | TECHNICAL
PROJECT EXAMPLE: REM METRO, MONTREAL
Advantages from the development of SFRC as a permanent lining are many, including for the REM Metro Project under construction in Montreal, in Canada. The advantages include: ● Environmental Impact: reduction of CO2 by using steel fibres rather than rebar ● Reduction of CO2
by having thinner tunnel lining, equating to less concrete used; also, more durable lining means a longer service life
● Cost Reduction/ Cost Performance: reduction in mass of steel required as well as there being no in-situ installation cost
● No formwork required, leading to savings in labour and build time ● Quality and safety can be achieved using the right product for the right use, specifying clear performance requirements and appropriate testing methods
The REM project is being built by a joint venture of SNC Lavalin, Aecom, Dragados, EBC, and Pomerleau. The final design is being performed by a joint venture of SNC Lavalin and Aecom. Once completed – scheduled for the end of 2024 – the REM project will be the 4th largest automated transportation system in the world. The project includes three underground stations in downtown Montreal,
one of which – Edouard Montpetit (EMP) Station – will be the deepest station in Canada upon completion.
The EMP Station is built within the existing double-track Mont Royal by reducing the mass of steel
Tunnel (MRT) with the side platforms constructed by enlarging the existing tunnel. Using the NATM method of excavation, the station utilises permanent rock bolts and shotcrete reinforced with steel fibres for both the initial and final linings of the station structures (tunnels, shafts, caverns etc.). First, a 5cm layer of steel fibre reinforced shotcrete is applied as initial support, then bolts are installed, and then a sprayed waterproofing membrane is applied. The lining work is finished with another 5cm of steel fibre reinforced shotcrete. The liner is designed for a 125-year service life. This configuration was first used in North America for a pump station
cavern in Indianapolis, but it is the first time this approach is used for a major transit station in North America. The advantages of this configuration are numerous both in terms
of design and constructability in comparison to the typical approach, which would consist of an initial temporary support, a sheet membrane and a permanent final liner. Effectively, the initial liner, which would typically be considered only as temporary support, now serves in both temporary and permanent functions, as this configuration allows load transfer from the initial lining to the final lining. As a result, the overall lining thickness is reduced when compared to the typical design.5
Above left: Cavern at Edouard Montpetit (EMP) station in Montreal, Canada Above right: Edouard Montpetit (EMP) station PHOTO CREDIT: AECOM
to consider and understand the idea behind the testing procedure selected. Testing a material is the same as asking a question. For example: How does this material react under the
specific conditions of this test method? Subsequently, an answer to the question can be retrieved from the results, and this answer can be shared or used for design or performance evaluation. Essentially, it is crucial to understand the test (question) that is being run (asked) and the result (answer) that is collected. In EN 14487-1, the European Standard for sprayed
concrete, Annex A mentions the following: “The different ways of specifying the ductility of fibre reinforced sprayed concrete in terms of residual
strength and energy absorption capacity are not directly comparable. ● The residual strength must be specified when the concrete characteristics are used in a structural design model.
● The energy absorption value measured on a plate with continuous support can be specified when, in the case of rock-bolting, emphasis is laid on energy which has to be absorbed during the deformation on the rock.”
EN 14487-1 prescribes differing ways of specifying the ductility of sprayed concrete. These include an EN 14488-5 energy absorption test, used in empirical
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