Projects with a value between R50 million and R250 milion
Plankenbrug Main Outfall Sewer and Associated Works - Phases 2 & 3 by AECOM for Stellenbosch Municipality, Western Cape
T
he existing Stellenbosch bulk sewer network along the
• 1 486 m uPVC collector sewers (DN 110 mm to DN 355 mm).
Plankenbrug River was under
The project also included:
strain. AECOM was appointed
• 94 concrete manholes
for full professional services to investigate,
pipe jacking DN 1 050 mm, 50 m horizontal directional drilling DN 250 mm) • reconstruction of 900 m municipal roadways following sewer
• two above-ground gravity flow sewer pipe
installation underneath
design, and manage the construction of
bridges (DN 350 mm and DN 1 000 mm)
• two open-cut railway line crossings.
urgent remedial actions required. This
across the Plankenbrug River, including
This project was considered challenging
appointment was to address the current
associated river hydraulic modelling
beyond the norm. The sewer had to be
• two temporary sewage pump stations
installed alongside a river located in a
capacity and pollution problem, as well as upgrading the system for a future estimated
(300 ℓ/s each) and one temporary
highly built-up area, which offered less than
sewage flow of over 900 ℓ/s, according to
screening station for sewage over-
7.5 m working width in some locations.
the Sewer Master Plan.
pumping around the construction works
This required careful and intrepid decision-
AECOM’s design proposal recommended
• reconstruction of a 150 m long x 4 m
making, as well as careful execution. In
the replacement of the existing problematic
high river retaining wall to protect the
addition, seasonal river flooding needed to
sewers with the following:
new sewer
be managed, particularly during the new
• 1 245 m HDPE-lined concrete bulk sewers (DN 900 mm to DN 1 000 mm) • 3 094 m GRP bulk sewers (DN 350 mm to DN 600 mm)
PROJECT TEAM
Client: Stellenbosch Municipality Consulting Engineer: AECOM Contractor: CSV Construction
• stormwater intercept structures to divert
river retaining wall construction. Several
polluted stormwater and low flow run-off
existing services were accommodated to
from the Kayamandi township into the
allow the gravity sewer to be built. With a
sewer network and not to the downstream
robust safety culture on-site, the project
Plankenbrug River
team completed the project in time and
• installation of bulk sewers by means of no-dig methods underneath live
within budget. The new bulk sewer will unlock upstream
provincial roadways and railway lines
housing development opportunities, for
(90 m microtunnelling DN 1 170 mm, 40 m
which there is a high demand in this area.
C E S A A o n E n g i n e e r i n g E x c e l l e n c e Aw a r d s 2 0 2 1
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