ABSTRACT
Once completed, the Montreal Réseau Express Métropolitain (REM) will be the fourth largest automated transportation network in the world. This project involves construction of a 2.5km of single-track bored tunnel made of precast fiber reinforced concrete (FRC) segmental lining which connects Montréal-Pierre Elliott Trudeau International Airport to the rest of light rail network. To accelerate the construction of Airport Tunnel, for the first time, steel fiber reinforced precast concrete units are adopted for building the tunnel internal structures including the separation wall between the egress corridor and the platform walkway, and the slab for egress and platform walkway. Because of higher quality of precast concrete compared to cast-in-place concrete, this solution also results in extending service life of structure. A rigorous geometrical analysis was conducted to size the precast units to allow for the alignment curvatures as well as construction and manufacturing tolerances arising from different sources, including tunnel ring rolls and segment offsets. A three-dimensional model of the internal structures was created using a finite element software to check the precast walls and the precast slabs capacities under design loads, including the train-induced aerodynamic pressure. In addition, to further accelerate the construction of Airport Tunnel and prevent damages to segment due to drilling, a system of embedded sockets in precast segments and prefabricated curved steel channels anchored to these sockets are designed to support train’s overhead catenary system (OCS). Before mass production of the precast units, a set of dowel pullout tests was completed by contractor on full-size precast segments to check the capacity of embedded socket/dowel connection system to the segmental lining. This project showed that with close collaboration among designer, contractor, and precast manufacturer, an accelerated and durable construction of bored tunnel’s interior structure using innovative precast units can be successfully realized which can have significant benefits for all parties involved.
