Resources

Glossary

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  • Abutment
    The substructure at the end of a bridge span on which the superstructure rests.
  • Adit
    An entrance to the underground tunnel that is horizontal or nearly horizontal, for example, the connection between the tunnel and a vent shaft.
  • Ballast wall
    Retaining wall or wall built on the top of an abutment that provides stability to the structure.
  • Bearings
    Used on the Highway 417 bridge structures (Lees and Vanier Parkway), steel plate bearings reduce friction between bridge piers and girders they rest on.
  • Bench
    Refers to the 'floor' or bottom of the tunnel that is typically excavated after the top heading has been completed.
  • Boring
    The process of creating or enlarging a hole. Boring technologies have been developed that produce deep holes with impressive accuracy.
  • Caisson
    Foundation element that is typically augured into the ground.
  • Canopy
    A structure that shelters transit users from inclement weather.
  • Catenary
    Catenary is a system of overhead wires used to supply electricity to light rail vehicles.
  • Conduit
    A pipe or tube used to protect electric wires or cables.
  • Curtain wall
    A non-bearing wall of glass, metal, or masonry attached to a building's exterior structural frame.
  • Dowel
    A solid cylindrical rod used as structural reinforcement.
  • Drifts
    Sections of the tunnel cavern station that are excavated in a predetermined sequence.
  • Falsework
    A temporary structure used in construction to support a spanning or arched structure until its construction is sufficiently advanced to support itself.
  • Formwork
    A mold used to form concrete into structural shapes such as walls, beams, columns or slabs.
  • Gantry Crane
    The type of crane used at the central shaft. Built atop a gantry, which is a structure that straddles the shaft, it is used to load and remove materials, such as muck or materials removed from tunnel, by a hoist, fitted in a hoist trolley.
  • Girder
    Steel or reinforced concrete beams used as a main horizontal support on a bridge.
  • Glazing
    Furnishing or fitting a structure, such as the Belfast Yard building, with glass panels.
  • Grade beams
    A grade beam is a foundation element. It consists of a reinforced concrete beam that transfers loads from a bearing wall into vertical sections such as caissons.
  • Head house
    A free standing entrance that leads to the concourse and platform.
  • Headwall
    A small retaining wall placed at the outlet of a culvert or stormwater pipe.
  • Hoe-ramming
    Hoe-ramming is a form of rock excavation, often used when an area is too large for a jackhammer or where blasting is not possible.
  • HVAC
    Heating, Ventilation and Air Conditioning vents, also known as HVAC vents, are used in the daily operation of the station. These function much the same way as HVAC vents would for other buildings in downtown Ottawa.
  • Infrastructure
    Basic facilities, services and installations needed for the functioning of a community or society.
  • Invert
    The interior base level slab, or floor, of the tunnel that supports the rail track bed.
  • Jet grouting
    A process of injecting concrete into holes in the ground to mitigate any loose or potentially unstable ground as tunnelling and cavern station work continues.
  • Knee wall
    A knee wall is a short wall – approx. one metre in height – used to support the roof rafters in construction.
  • L-Walls
    L-Walls are built in the station caverns as part of the lower level support system in drifts.
  • Lattice girder
    Reinforced beams consisting of diagonal pieces crossing each other (similar to latticework). Girders are used as horizontal support in the tunnel.
  • Micro-piles
    The process of drilling small round steel sections into the ground to reinforce it.
  • Micro-piling
    The process of drilling small round steel sections into the ground to reinforce it.
  • Milling
    The process of removing asphalt pavement with a milling machine.
  • Mud slab
    A layer of concrete, poured below a structural element but above a layer of soil.
  • OCS
    The OCS (Overhead Catenary System) refers to the overhead wires used to supply electricity to light rail vehicles.
  • Overhead Catenary System
    The OCS (Overhead Catenary System) refers to the overhead wires used to supply electricity to light rail vehicles.
  • Parapet wall
    Parapet walls on bridges and other highway are safety structures prevent users from falling off where there is a drop in the infrastructure.
  • Petrucco Verona System
    A system patented by the Italian firm, Petrucco Group, the Verona System was a concrete box structure used to reinforce and support VIA Rail tracks while work took place beneath them as part of the work on the Belfast Yard connector.
  • Pier bents
    Vertical frames erected to support elements of the superstructure, such as beams and girders.
  • Pier cap
    The upper part of a bridge pier, intended to distribute loads evenly over the pier's area. Used in foundation work, piers are installed alongside grade beams as a means of supporting a structure’s load.
  • Piling
    A construction activity where vertical steel pieces are put into the ground to reinforce it. Piling can include “H piling” which requires shoring or “secant piling”. “H piling” uses a large crane with a weight attached to bang piles into place causing a loud, repetitive, banging noise. “Secant” involves drilling holes and filling them with concrete and is less noisy than “H piling”. The type of equipment that could be used for piling are cranes, welding trucks and mechanical trucks.
  • Plenum
    The area located beneath the floor or above the ceiling that is used to house electrical and mechanical systems in various stations.  
  • Plinths
    Bases or platforms upon which columns or structures rest.
  • Precast concrete
    Concrete that is made in a reusable mold or "form" which is then transported to the construction site and lifted into place.
  • Rebar
    An abbreviation of reinforcing bar, rebar is a mesh of steel wires commonly used as a tension device, to strengthen and hold the concrete in compression.
  • Reinforced Steel Structure
    Reinforced Steel Structure (RSS) walls are retaining walls that restrict movement of soil.
  • Rock bolt
    Rock bolt is a long anchor bolt, used to stabilize rock excavation in tunnels. It transfers load from the exterior to the stronger interior of the rock mass.
  • Rough-ins
    The layout of various utility lines (plumbing pipes, duct work, electrical conduit, etc.)
  • Scrubbers
    Air treatment systems that remove particulate matter or debris from the air exhausted from the tunnel.
  • Shaft
    A shaft is a vertical or inclined passageway.
  • Shoring
    Reinforcement of excavated areas. A good example is visible on the ramp that forms the West Portal tunnel entrance.
  • Shotcrete
    Shotcrete is projected concrete used to reinforce the walls of the underground tunnel.
  • Soffit
    The underside of a structural component, such as the underside of one of the bridge’s or superstructure’s deck along Highway 417.
  • Spiles
    Protective pre-support system used in tunneling.
  • Substructure
    Substructure works involve work on the foundation and work below surface.
  • Superstructure
    Structure de surface.
  • Tamping
    Large machine called a tamper lifts the rail with its hydraulic jacks and clamps and uses its four hydraulic vibratory claws to drive down into the ballast on either side of the tie and squeeze the ballast under and against the tie. The rail is then in its final position and the process is repeated at each tie.
  • Tension ties
    Temporary structural component designed to reduce lateral loads during excavation and tunneling work.
  • Tieback
    A horizontal wire or rod, or a coil-like anchor used to reinforce retaining walls for stability. With one end of the tieback secured to the wall, the other end is anchored into the earth with sufficient resistance.
  • TPSS
    TPSS structures are approximately four metres high by five metres wide by 15 metres long. They convert electricity from the local power sources to the voltage levels needed by the LRT vehicles.
  • Traction Power Sub Station
    TPSS structures are approximately four metres high by five metres wide by 15 metres long. They convert electricity from the local power sources to the voltage levels needed by the LRT vehicles.
  • Transition
    The area where the Confederation Line tunnel begins to widen. Transition areas are found between the running tunnel and the station caverns.
  • Umbrella
    Support structure comprised of steel pipes that is used during tunneling excavation.
  • Whalers
    Horizontal reinforcement used to secure upright structures, such as formwork for the pouring of concrete.
  • Wing walls
    Walls that project from the abutment of a bridge to support or reinforce it.