40
CONSTRUCTION EUROPE
SEPTEMBER 2013
FOUNDATIONS
Firm foundations
There are a great many factors to consider
when installing foundations or improving
soil conditions, and the bigger the project,
the bigger the potential impact.
Helen
Wright
digs deep into the sector
M
anufacturers
of
equipment
for the foundations sector are
constantly
developing
new
technology to speed up efficiency and reduce
environmental impact, while working closely
with contractors on projects plays a central
role.
Gerhard Frainer, managing director of
GOOD VIBRATIONS
Dong Energy tested a trio of 200HD PTC
Vibrodrivers during construction of the Anholt
wind farm – a 400MW development that will
be Denmark’s largest offshore wind farm
when complete.
The project requires 275 tonne monopiles
to be driven into the sea bed as foundations.
Powered by three PTC 1200C power packs
supplying a total power of 2418kW, the
Vibrodrivers worked in synchrony to install
the piles to a depth of 20m. They achieved this
in less than 30 minutes while emitting under
160dB at 750m distance.
PTC’s latest Vibrodriver is the 20RHFV model,
which has been specially designed for working
on piling rigs. Equipped with variable moment
technology, the 20RHFV boasts a reduced
centre width of 450mm, whichmeans it can be
fitted through two sheet piles when installing
a sheet pile wall. Users can therefore drive or
extract sheet piles more rapidly because they
Liebherr’s new 350 tonne HS
8300 HD duty cycle crawler
crane uses a hybrid drive
system that is said to be
both powerful and energy
efficient
construction machinery sales at Liebherr, said
that a clear trend in recent years had been
towards construction site, application and
process consultation.
He said Liebherr had made this trend of
moving away from machinery manufacturer
towards a complete systems supplier part of
its strategy from an early stage.
“In the deep foundation area in particular,
we have for a long time now adapted our
internal processes to comply with this
trend. For example, the compendium which
we publish on process technology and
equipment selection has acquired the status
of a standard work of reference within a very
short time,” said Mr Frainer.
New equipment introduced this year
includes the LB 44 rotary drill rig, which can
reach a depth of 92m and as such is well-
suited to deep foundations work. Despite
its size, Liebherr claims this unit presents no
transportation problems and is highly mobile.
And the company’s new 350 tonne HS 8300
HD duty cycle crawler crane is also said to be
well-matched to foundations work. It uses
a hybrid drive system, called Pactronic, that
is described as both powerful and energy
efficient. This system uses a hydraulic
accumulator to store surplus energy which
is then released when required, improving
performance and reducing fuel consumption
and, therefore, environmental pollution.
Hydraulic free-fall winches offering some
50 tonnes of line pull are fitted, and critical
parts of the machine have been reinforced
with carbon fibre. The crane can carry a range
of attachments, including hydraulic clamshell
grabs.
Meanwhile, vibratory hammers, which
produce vertical vibrations to drive or extract
foundations such as sheet piles, are growing
in popularity both in their own right and as
an alternative to hammering piles into the
ground, according to manufacturer PTC.
Owned by Fayat group, PTC said it had
seen a growing interest in its Vibrodriving
technology in the offshore wind farm
sector in particular. It said the increasing
concern in reducing underwater noise
emissions during offshore pile driving to
protect marine life was motivating offshore
wind farm contractors to start looking for
more environmentally sensitive techniques.
