2. Repair and Strengthening
Solutions
CCL is known and trusted around the
world for its technical expertise in
concrete design and construction.
A specialist in prestressed concrete technology, the Company also
provides innovative solutions for the repair and strengthening of
concrete and steel structures on building, civil, energy and marine
projects. Experience gained from work undertaken across the globe
has ensured that the company remains at the forefront of its field.
Site inspection
The Need for Structural Repair and
Strengthening
Throughout the service life of a structure surveillance and
maintenance will be required in order to ensure the preservation
of structural integrity. Most structures will have need of at least
minor remedial action, but some will require a greater degree of
intervention. Repair and strengthening may be called for because
of site defects which occurred during the construction process,
change of use, design code changes, the need for additional load
capacity, or to accommodate building modifications. General
deterioration may be caused by age or environmental attack.
CCL has a long history of providing specialist concrete construction
solutions. Its strength lies in correctly identifying the problem and
its cause, understanding the needs of the client and interpreting
their requirements to develop the most appropriate solution, using
the latest methods and technologies.
Maintenance
Inspection and maintenance carried out on a regular basis can help
to reduce the need for major structural repairs. CCL will perform
maintenance checks including corrosion inspection and load
checking, and if necessary, will replace post-tensioned strands.
Specialist teams will examine the structure, identify any areas of
concern, and recommend appropriate action.
The CCL Approach
CCL’s approach begins with inspection and evaluation. This
fundamental stage allows the Company to correctly identify the
problem and to understand the underlying cause. Inspection may
take the form of a visual survey and may also involve carrying out
destructive or non-destructive testing to ascertain details such as
strength or depth of concrete, degree of corrosion or positioning of
reinforcement.
CCL will then liaise closely with the client to gain full appreciation
of existing conditions and future requirements. Only then can CCL
Engineers compile their findings, assess the potential solutions and
submit their proposals.
Surveying concrete to locate reinforcement
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3. Strengthening
Structural strengthening requires the
careful and considered input of qualified
engineers. It may be necessary because
of changes in load capacity, concrete
deterioration, construction faults or the
need for additional slab openings. CCL’s
teams of structural and civil engineers
use their expertise in concrete design
and construction and their extensive
international experience to determine the
most suitable solution for each individual
application.
Back span tie down of bridge deck
External post-tensioning
CCL will conduct a full inspection before compiling a report
containing details of the findings and any recommendations
deemed appropriate. The Company can also provide a monitoring
service to identify potential problems, allowing prompt remedial
action to be taken.
CCL has the capability to deal with strengthening problems
using a variety of techniques including the addition of steel
reinforcement or steel plates, external post-tensioning and
carbon fibre reinforced polymer (CFRP).
Post-tensioning and associated prestressed concrete
technology provides an efficient means of effecting structural
strengthening. It is used in all sectors of construction including
buildings, civil, marine and energy. As well as providing additional
strength, external post-tensioning is used to control deflection,
stresses and cracking of concrete.
CFRP applied to underside of slab
CCL structural solutions also include carbon fibre reinforced
polymer (CFRP) applications which provide durable, maintenancefree external reinforcement. CFRP is a versatile material which
can offer a long-term, corrosion-free, strengthening solution.
Although of a very high strength, CFRP is extremely lightweight
and cost-effective. The woven fabric is bonded to the prepared
concrete using high performance adhesive and can be used
to provide additional reinforcement in situations calling for
increased load capacity, structural modification, damage repair or
correction of building defects.
As part of its structural repair and strengthening service CCL
offers a bearing and expansion joint package which includes
inspection, refurbishment and replacement.
Remedial to increase punching shear capacity
Aramid strengthening around slab opening
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4. Concrete Repair
The reasons for damage to concrete can
be many and varied, including impact,
exposure to aggressive environments
and reduced cover.
Deterioration may cause spalling and hasten corrosion of the
reinforcement, which in turn can reduce flexural strength and may
result in failure.
Before remedial work is undertaken the extent of the damage
and its underlying cause must be established.
Repair and refurbishment of defective concrete can be carried
out successfully using a variety of materials. CCL has provided
specialist concrete repair systems for many different applications
from grout anchors in concrete slabs to mass filled voids below
concrete pipes. The use of grout and resin injection is a proven
method of dealing with cracks in concrete structures in order to
prevent ingress of water or gases.
Grout anchor at post-formed opening in slab
The Company has undertaken grout injection repairs to buildings,
large civil structures and power plants. Each grouting problem is
unique and CCL specialists will assess each application to fully
understand the problem before advising on the most appropriate
solution.
Resin injection is also part of CCL’s concrete repair solutions
package. Epoxy resin injection can produce impressive results,
knitting together fragile and fractured structures and providing
protection against corrosion. In addition to epoxy resins flexible
polyurethane can be used to allow a greater degree of movement
in the structure. Although not structural, these resins can be used
to bond cracks or joints to prevent water ingress.
If carried out correctly, grout or resin injection can result in the
restoration of full structural integrity and can extend the service
life of the structure.
Resin injection applied to cracked concrete
Void filling to combat delamination
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Diamond cutting
5. Jacking and Lifting
CCL can offer a range of lifting, jacking
and weighing services as either a
stand-alone option or as part of a
structural repair package for buildings
or civil structures.
Cylinder jacks are provided as single acting, double acting, locknut design, custom mount, custom stroke and custom bore
models. Flat jacks, which are ideal for low height or restricted
access situations and require only minimal space for installation,
can be used for permanent or temporary applications. When
installed on a temporary basis hydraulic oil or water is used for
inflation. For permanent location cementitious grout is used.
These highly skilled operations are carried out by CCL specialists
or under their direct supervision. A full project review will be
conducted to identify the most appropriate method of propping,
lifting, lowering, sliding or weighing a structure. CCL has a
flexible approach and can tailor a solution to meet the specific
requirements of the project, while ensuring that safety remains
the highest priority.
Temporary propping to to secant pile walls
Temporary propping secant pile walls
Grout filling a flat jack to preload the retaining prop
Preloading of retaining prop using cylinder jack and locking collar
Preloading of retaining prop using flat jack
Cylinder jacks with locking collars providing temporary support
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6. Bridge Bearings and
Expansion Joints
The replacement of key components
such as bearings and expansion joints is a
common aspect of structural repair
and strengthening.
CCL’s comprehensive bridge bearing and expansion joint
package includes inspection, design, supply, refurbishment and
replacement.
Bridge bearings are designed to transfer loads, provide restraint
and allow rotation, while accommodating displacements caused by
shrinkage, creep, live loads, variations in temperature and seismic
activity. CCL specialises in the bespoke design of bearings which
meet relevant local and international standards and exactly match
the requirements of the project.
Bridge bearings
The maintenance or replacement of both bearings and expansion
joints should always be entrusted to experienced professionals.
CCL recognises that every project is unique and will work to find
the optimal solution for each situation.
Following a detailed inspection CCL will provide a comprehensive
report recommending appropriate action. Where remedial
measures are required the Company will ensure these are carried
out safely and efficiently, causing minimal disruption.
The role of expansion joints is to allow movements in a structure
which may be induced by creep, the effect of shrinkage, thermal
changes and the imposition of live loads.
Installation of expansion joint
Bridge bearing replacement
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Expansion joint from below prior to installation of edge control system
