Keller is a leading international ground engineering specialist.
With a turnover in 2007 of £955.1m, it has around 6,200 staff
world-wide with offices in over 30 countries on five
continents.
Around the world, ground engineering is crucial to the success
of major civil engineering schemes such as urban regeneration,
infrastructure renewal and energy production. It is also an
important factor in whether a project is delivered on time and to
budget. Whatever the size of the project, and wherever it is,
Keller has the experience and technology to provide an innovative,
robust and cost effective solution.
In the last 10 years, Keller has delivered compound annual
growth rates in sales and operating profit of 17% and 24%
respectively, through a combination of organic growth and
acquisitions. Today, it is the number one player in the US and
Australia; it has leading positions in established European
markets; and has a strong profile in many emerging
markets.
Keller has successfully developed ground engineering techniques
that are now widely accepted in the construction industry and some
of which are illustrated in the
“case studies” section of
this website.
What Keller offers clients
Our clients tell us they like us because we are experts and
innovative; they like the fact that we work with them to find the
best and most cost-effective solution from an informed engineering
and construction viewpoint. We have been described as “the
hidden giant” - not just for the obvious reason that most of
our work is buried in the ground, but also because it recognises
our inherent strength and capabilities.
Although we are a global player we have a strong local presence
in all our markets; so we can respond quickly to our
customers’ needs and changes in our marketplace. Wherever we
work and whatever the size of the project, we bring strong
contracting relationships, good logistics, specialist technologies
and equipment, experience and excellent risk and safety
management.
What Keller offers employees
One of our strengths is the huge expertise and in-depth industry
knowledge of our people. Keller attracts quality people who are
motivated by the culture of empowerment, excellent job support,
good reward and recognition and opportunities for career growth.
Our engineers appreciate our continued investment in research and
development and active encouragement of technology transfer between
our companies. This means new techniques can be introduced into
geographic markets in the knowledge that support is available
elsewhere in the Group from engineers experienced in those
techniques. The average length of service for Keller employees,
including field and administrative personnel, is around eight
years.
What Keller offers investors
Investors like the way we spread risk, our strong brands and
solid track record.
Over the years we have delivered strong organic growth, as well
as good contributions from acquisitions. Operating profit has
trebled in the past three years to £104.7m in 2007, whilst
earnings per share from continuing operations have risen by a
compound annual growth rate of 21% over the past 10
years.
For a specialist player we are also extremely diverse. Our
geographical spread, mix of public and private clients and the
balance between new-build and refurbishment work means we are
largely protected from economic and political cycles.
Time and again we have seen our acquisitions integrate
successfully into the Group and then grow. The prospects for
future long-term growth are good, with continued opportunities for
technology transfer and potential for further consolidation in an
industry that remains largely fragmented.
Our services
A brief overview of our principal services is given below.
Customers visiting this website who are looking for specific
information about the services offered by Keller companies or who
have a technical enquiry are invited to visit the websites of our
operating companies (see the link to Keller Websites above).
Ground improvement
Ground improvement techniques are used to prepare the ground for
new construction projects and to reduce the risk of liquefaction in
areas of seismic activity.
Keller was the first to develop methods and equipment for the
successful deep compaction of soil in the 1930s and has since
developed the equipment and widened its application. Common soil
stabilization techniques include a combination of vibro-compaction
with stone, concrete or lime columns as well as soil mixing and
injection systems. The techniques have been used by Keller to
improve many thousands of sites around the world, from housing
projects to power plants, from dam foundation to industrial and
commercial developments.
Ground Improvement – Vibro Stone Columns
- Assisted by water jetting, the vibrator penetrates to design
depth under its own weight. The jets then maintain a space around
the vibrator.
- Crushed stone backfill is introduced in discrete lifts. The
horizontal forces of the vibrator laterally compact the stone
against the surrounding soil.
- The process is repeated up to ground level, forming a well
compacted, tightly interlocked stone column surrounded by soil of
enhanced density.
Specialty grouting
Specialty grouting strengthens target areas in the ground and
controls ground water flow through rocks and soils by reducing
their permeability.
Specialty grouting is applicable to both new construction
projects and to repair and maintenance work. Other applications
include excavation support, settlement control and
geo-environmental services such as diaphragm (slurry) walls to
protect adjacent ground from contamination. Common techniques
include compaction grouting, jet grouting and fracture
(compensation) grouting. Particular techniques developed by Keller
include Soilcrete jet grouting, which enables grouting to be
applied to a very wide range of soil types compared to traditional
methods, and Soilfrac compensation grouting.
Specialty Grouting – Jet Grouting
- Pre-drilling or foundation coring may be necessary to access
treatment zone. Drill monitor is inserted to required depth.
- Since jet-grouting is a bottom up procedure, erosion is
initiated at design depth with high velocity injection of cutting
and replacement fluids.
- This continues with consistent, uniform rotation and lifting to
create column geometry, while expelling eroded soil out of the top
of the borehole.
- Designed integration of adjacent columns creates a soilcrete
mass.
Soilfrac compensation grouting finds particular application in
the control of ground movement above tunnelling works. Soilcrete
and Soilfrac technologies have been used in many of the
world’s major cities during construction and renovation of
underground systems, including the Jubilee Line in London, the
Metro system in Lisbon, and infrastructure renewal in Berlin.
Piling
Piling involves the installation of structural elements to transfer
foundation loads through weak soils to stronger underlying
ground.
Keller offers a wide range of piling systems including
mini-piles, sheet piling and deep large diameter caisson piling.
Piles may be preformed and driven into the ground or cast in situ.
Keller has installed piles underpinning many major building and
civil engineering projects around the world.
Piling - Continuous Flight Auger Piling
- The pile is formed by first drilling into the ground with a
continuous flight auger.
- Cement-sand grout or concrete is then injected under pressure
through the auger's hollow stem as it is being withdrawn.
- The grout or concrete pressure is maintained during withdrawal
to assist the extraction as well as exerting a lateral pressure on
the surrounding soils.
- On completion of this operation, a reinforcing cage is placed
into the fluid column of grout or concrete.
Post-tension cable systems
Post-tensioning is used to reinforce concrete foundations and
structural spans, enhancing their load-bearing capacity by applying
a compressive force to the concrete, once set.
Post-tension technology has been used in North America since the
mid 1960s and has been used increasingly in the residential and
commercial construction markets. Cost savings in labour and
materials, along with the enhanced design flexibility, compared
with more traditional reinforcement methods, have driven the
increasing trend towards post-tension cable systems. Post-tension
reinforcement foundation slabs are particularly appropriate for the
soil conditions found in Texas, California and Arizona, where
Suncoast has developed its principal operations.
Post-Tension Cable Systems
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