As part
of an ongoing project to extend University Avenue, one of the main
arteries in Waterloo, Ontario, the City of Waterloo recently completed
construction of the bridge at Colonial Creek. In response to environmental
concerns, MTE Consultants designed the bridge to minimize the impact
of the roadway over an existing creek.
The
bridge deck and abutments are constructed of reinforced concrete and
are abutted on all sides by segmental retaining wing-walls with geogrid
reinforcement. The four wing-walls run nearly parallel with the existing
water course and perpendicular to the bridge. Based on the location
and proposed use, the design of the segmental retaining walls had
to comply with several additional criteria.
Acting
as bridge wing-walls, the analysis and design was conducted in accordance
with the Ontario Highway Bridge Design Code, which currently calls
for slightly higher margins of safety than the NCMA Design Manual
for Segmental Retaining Walls. The presence of a creek in front of
the wall required that special attention be paid to drainage at the
wall face, scour protection and the wall embedment depth.
Finally,
in an effort to minimize overall costs, the geogrid reinforcement
design was optimized to allow reduced lengths as the walls tapered
down to grade. At the maximum height, the segmental retaining walls
(SRWs) stand approximately 7.7m (25ft), then taper down rapidly (2.5H:1V)
to near grade. For erosion protection, rip-rap is positioned in front
and at the ends of the walls. The total face area of the walls
is approximately 325 m2 (3500 square feet).
These
walls highlight the capacity of the segmental retaining wall system
to combine rugged performance with an aesthetic quality rarely found
in heavy highway and bridge applications. With aesthetics becoming
an increasingly important issue in large commercial and government
projects, the solid strength and lasting beauty of the SRW system
proves to be an attractive alternative to other retaining wall systems.
Landscaping
|
Roadway Applications | Bridge
Abutments | Design
and Construction
Building
Applications |
Interlocking Concrete Paving | Segmental
Retaining Walls | Articulated
Concrete Block Paving | Concrete
Masonry Units
