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CONSTRUCTION WORLD
JULY
2015
PORTS AND HARBOURS
Franki engineer Paul Pearce says
the existing pier is a reinforced
concrete deck supported on
precast concrete piles which retain
a rock groyne beneath the pier. “Due to scour
and failure of the precast piles, approxi-
mately 75 m of the seaward end of the pier
has failed and is to be demolished and recon-
structed,” Pearce says.
The main scope of works includes the demo-
lition of 75 m of the existing piling and deck;
installation of 22 no. 750 mm diameter x
24 m permanently cased piles; construc-
tion of 75 m x 10 m wide new deck and
the installation of 500 no. 4-ton geotextile
scour protection bags within and around
the seaward end of the pier. “The existing
pier has continued to move due to the failed
piles and in order to safely demolish the old
pier and construct the new one, we have
constructed a 110 m temporary jetty adjacent
to the existing structure as a working plat-
form,” Pearce says.
The temporary jetty was completed in
June 2014. Obstructions, including large
boulders and concrete, below the sea bed
have caused difficulties in installing piles
and these had to be broken through using
chisels and grabs resulting in lengthy delays.
Where the existing failed piles obstructed
the proposed new pile positions, the jetty
has had to be redesigned to accommodate
new pile positions. All piles have now been
installed to depth, with one pile having to be
installed at a rake.
Ongoing settlement of the rock within
the groyne and in the sea bed around the pier
are causing the engineers some
concern and additional scour protection
measures are being taken to stabilise the
situation and ensure the groyne serves its
intended function of beach sediment control
– and producing a decent, but safe, wave for
the surfers.
Reconstruction of the deck has started
at the seaward end of the pier with the
existing structure being cut into manageable
pieces and removed to dump. The existing
precast piles are being braced and incorpo-
rated into a new capping beam below the
new structure.
The new deck, which will be approximately
4 m wider than the existing deck, will be
constructed in 11 sections. Custom shut-
tering supported on the new and the existing
piles is being used. The deck design and
the formwork have had to be modified to
accommodate the revised pile positions and
the raked pile.
As with all marine works, the risks associ-
ated with rough sea conditions are ever-
present making the fixing and maintaining
of the deck shuttering challenging. One of
the measures taken to speed up preparation
works to avoid the exposure time is the use
of glass fibre coated polystyrene blocks for
soffits and void filling.
Currently Franki’s Siva Govindasamy, a
veteran Durban pier builder having worked
on Dairy Beach Pier, uShaka Pier, Umhlanga
Pier and the more recent Argyle Stormwater
outlet, and James van Wyk are supervising
the works.
Due to the unforeseen ground condi-
tions and associated delays, the works are
currently behind schedule with contract
completion scheduled for December 2015.
Bay of Plenty
PIER
After a lengthy delay due to an appeal against the award, Franki
Africa (KZN) was appointed by eThekweni Municipality in October
2013 to carry out the reconstruction of the Durban Bay of Plenty Pier
and commenced work in March 2014.
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