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BEST
PR
O
JECTS
74
CONSTRUCTION WORLD
DECEMBER
2015
Professional Services
C
In 2005, the South African National
Roads Agency Limited (SANRAL)
found signs of distress and exten-
sive cracking in the 14,23 km, two-lane
pavement of Section 11, National Route
2 between Soutwerke and Colchester in
Eastern Cape.
Concerned about the health and safety
risk the damage posed to drivers, the
SANRAL appointed the Semenya Aurecon
joint venture (JV) to rehabilitate the route,
which runs north-east and ends at the inter-
section to Colchester. The appointment
included detail assessment, detail design
and documentation.
In the assessment stage, it was also
found that the Coega Industrial Develop-
ment Zone (IDZ) development – the largest
of its kind in South Africa – would generate
traffic that would require a dual highway
by 2015.
Taking this factor, the financial viability
of an upgrade, the existing road’s struc-
tural condition, and road capacity implica-
tions into account, SANRAL then decided
to not only rehabilitate the two-lane route,
but to also upgrade it into a four-lane
divided highway.
The new bridge is 201,18 m long and
consists of six spans, each 33,53 m long.
The deck is supported by five piers and two
abutments that are all founded on piles.
Each deck span consists of six precast,
pre-stressed concrete beams.
Permanent formwork in the shape of
precast concrete planks was placed between
the beams before casting the in situ deck
slab. The deck is made continuous over three
spans during the casting of the in situ deck
slab to reduce the number of high-mainte-
nance expansion joints.
The successful construction of the new
bridge over a perennial river with challenging
conditions as well as raising the decks of the
existing bridge required innovative design
solutions and construction techniques, such
as the implementation of a meticulous and
sophisticated technical design process that
made extensive use of AutoCAD 3D.
The addition of a new bridge over
the perennial river provided the project
team with an opportunity to incorporate
innovative design elements to ensure the
optimal safety of the road for the increasing
amount of travellers, as well as serving as
an aesthetically pleasing addition to the
upgraded route.
Project information
• Company entering: Aurecon
• Project start date: 2013
• Project end date: 2014
• Client: SANRAL
• Main contractor: Concor Holdings
• Subcontractor: Ibhayi Contractors
• Consulting engineer: Dura Soletanche
Bachy, Semenya Aurecon JV
Sundays River Bridge
By incorporating aesthetic components
throughout the design and construction
phases to ensure the functional efficiency
of the aesthetic elements, the project team
delivered a product which serves as a
model of an efficient, safe and aesthetically
pleasing design.
The bridge site is approximately 3 km
from the ocean in a very corrosive envi-
ronment. The decision to use concrete as
the construction material for this project
was based mainly on its excellent dura-
bility characteristics.
Pre-stressed concrete beams were used
for the main structural elements of the deck,
with a composite precast permanent shut-
ters and in situ concrete deck slab.
The final construction value of the new
bridge came to R44 157 000 compared to a
tender amount of R42 760 000. The construc-
tion cost of R16 300 per square metre of deck
area compares well with similar bridges,
especially when considering the very deep
piled foundations.
The construction of the new bridge over
a perennial river with challenging condi-
tions, as well as raising the decks of the
existing bridge, required innovative design
solutions and construction techniques.
The bridge was successfully commis-
sioned in June 2014 and has seen the
road conditions and safety significantly
improved, as well as being able to accommo-
date the growing traffic volumes generated
by the Coega IDZ.