Les exposés écrits du congrès ont été publiés dans la langue dans laquelle ils ont été soumis à l’ATC.
A transit maintenance yard has been designed to facilitate the expansion of the public
transportation system in Metro Vancouver. The project involves several key yard structures,
including a single-span road overpass, retaining walls, and a guideway embankment that
have been designed to address and resolve numerous site constraints. The paper will
discuss these constraints and their successful resolution, including design rationale and
criteria adopted in the detailed design which was completed in March of 2024. The yard is
bounded by both existing heavy rail tracks and an underground pipeline to the north, a river
to the east and south, and a major road to the west. This necessitates careful planning and
design to accommodate the proposed maintenance buildings, utilities, and transit tracks
within the limited space. Proximity of the pipeline and river also involved constructability
considerations in the design. The road overpass is a 30-meter long single-span prestressed
concrete box girder bridge gaining access to the interior of the storage tracks. It features a
clear deck width of 7.150 meters, accommodating one lane of oversized tra8ic in each
direction for the delivery of transit cars to/from the site, with a raised sidewalk on the south
side. The superstructure is supported on MSE wall perched abutments with concrete
spread footings founded on granular pads. Box girders were chosen for their benefits in
minimizing formwork and field adjustments, particularly in seismic design. Three Retaining
Walls (RWs) serve various functions, including retaining access roads and parking lots,
providing grade separation for the yard access, future tracks and sidewalk. RW1 is a castin-
place concrete cantilever wall, selected for its ability to accommodate buried utilities.
RW2 is a reversed cantilever wall, designed to maximize site usage while maintaining grade
separation from an existing adjacent roadway. RW3 utilizes top-down excavation and
permanent soil anchors to minimize excavation costs. The guideway embankment
employs standard precast MSE retaining wall structures to address geometric constraints
and mitigate settlements. Miscellaneous other walls, including Lock Block walls, are
designed to meet specific site requirements and maintain grade di8erences. The design
adheres to the Canadian Highway Bridge Design Code CSA S6:19 and the BC Ministry of
Transportation and Infrastructure standards. Seismic design considerations are based on
site-specific geotechnical reports, with the site classified primarily as Soil Site Class C. The
road overpass is assigned to Seismic Performance Category 3, ensuring compliance with
performance criteria for single-span bridges.