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CONSTRUCTION WORLD
JULY
2016
Introduction
Geotechnical work in the marine environment
demands creative solutions to complex chal-
lenges. That’s the nature of the game and there
is no one better at it than Franki Africa, which
has developed a reputation throughout Africa
for its innovative and cost-effective solutions.
It is interesting that in both the marine projects
below, one of the common themes is great
teamwork – a perennial Franki skill.
COVER STORY
Project 1: Dormac Quay Wall
The first project is the construction of a
180 m-long, 16 m-high (4 m above water
and 12 m under water) quay wall for marine
engineering company Dormac’s new floating
dock at their marine works facility at their
Bayhead, Belfast Road site in Durban. Ship-
ping is renowned for tight schedules and high
operational costs and this project is subject
to the same pressures in order to meet the
schedules of the future users of the dock.
Franki Africa’s Paul Pearce says that
this has been a complicated, multifaceted
contract. “Although it is one structure, it has
required many highly specialised geotech-
nical skills for a successful outcome,” he says.
One of these skills was specialised jet
grouting using a rig from Franki owner Keller’s
German division. “In fact the co-operation
between Franki and Keller Germany was most
helpful,” says Pearce, “and confirms
the supreme advantage that we have being
part of the Keller network and able to tap
into the best technology and equipment in
our industry.” He adds that the jet grouting
was a highly technical and complicated ope-
ration requiring top-end management, opera-
tors and support. “After a three-week training
and test phase, the jet grout operations
began and, after some initial hiccups with
Franki Cape Town coming to the rescue with
their experience in jet grouting, we were able
to source the faulty parts from Europe and
continue with a productive and successful
operation,” Pearce says.
There have been a few significant chal-
lenges on this job with the first, as expected,
having to work in tidal conditions and being
exposed to the moods of the ocean. The
Franki crew worked around the clock to
accommodate tidal movement and, operating
when they could; they lay down a high-spec
working platform for the piling rigs. “This was
an exacting job to say the least,” says Pearce,
“but when it was complete we were able to
work with the sea being kept at bay and the
biggest risk to our operation allayed.”
The second challenge from a piling
perspective was the positioning and tol-
erance of the piles in relation to the jet grout
columns. “It was critical to get the positioning
spot on to ensure a vertical face to the
quay wall,” Pearce says. “Our works depart-
ment came up with a very innovative idea
in the manufacture of special guides and
frames to assist us in placing the piles in
accordance with the fine tolerances and
this worked perfectly.”
Piling challenge number three – to
increase our piling production rates – was
FRANKI SHOWS ITS
MARINE EXPERTISE
A panoramic view with the South lead-in jetty
being dismantled (on the left), the North lead-
in jetty completely dismantled and existing
piles cut off at low water mark. In the centre
are grid-lines C and D with the capping beams
and decking in progress (done by Haw & Inglis),
and on the right Franki is busy installing
casings on the 15
th
bay on grid-lines A and B.
1 3
2
Quantities on the
Dormac project
230 no. x 900 mm diameter CFA piles
24 m deep; 180 no. x 800 mm diameter
jet grout columns 16 m deep; 180 m
long x 5 m high quay wall capping
beam; 1 500 m x 63 mm diameter
tie bars; 80 000 m³ dredging and excava-
tions; 6 000 m² new dock yard
surface with services.
Pearce says that Franki is concluding
installing the capping beam and are
currently busy hanging the facial panels
on the quay wall. “This has been a chal-
lenging project but we are proud of our
ability to work in marine conditions
– a skill that we have acquired
throughout the company over many
years. Apart from knowledge and expe-
rience, the most important ingredient
for jobs of this nature is teamwork and
we had that in abundance on this job,’
concluded Pearce.
1. Exposed CFA piles and jet grout
in-fill columns.
2. Quay wall face panels around north
mooring pawl position.
3. Overview of site showing dredging and
CFA piling in progress.