Creagh Concrete is a key supplier to the education market with a range of offsite concrete products for school, academy and university projects. The fast track advantages of Creagh’s offsite build systems and precast components can meet the needs of time sensitive education schemes.

 

Concrete’s inherent properties are ideally suited to the education sector, its reputation for durability offers important savings in repair and maintenance within the school environment. Further whole of life savings can be attributed to concrete’s thermal mass which is acknowledged to be a valuable solution to the problem of overheating and its associated cooling costs.

Creagh can supply a wide variety of external finishes bringing design freedom that challenges other offsite building systems whilst details such as solid floors and insulated walls deliver concrete’s acoustic benefits and contribute to a buildings fire safety.

 

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Here are a few examples of Creagh’s education projects:

Constructing the largest redevelopment at London School of Economics

This project for London School of Economics (LSE) involved the construction of a state of the art flexible and highly sustainable academic and teaching building, designed by renowned architects Roger Stirk Harbour + Partners.  It also included a new public square at the campus for LSE’s largest ever redevelopment.

Creagh’s scope of work involved the supply and installation of 13 stories of hollowcore flooring, grouting and structural topping for the building. Collaboration was key throughout this build due to the confined inner-city site and complexity of the requirements, which contributed to the success of the project.

Toronto Primary School

A new purpose built extension was added to Toronto Primary school, comprising a monolithic textured precast concrete games hall that opens up to the school playing fields.  Creagh manufactured the textured concrete band which is punctured only at high level by way of a sandblasted pattern across Reglit apertures, conveying the pattern of the surrounding tree lined avenue.  The concrete wraps the entire base of the extension. Creagh also created a prominent internal feature wall panel for the reception area with both recessed and protruding lettering showing a bespoke design incorporating words chosen by the primary school pupils.

University of Greenwich

McLaren Group turned to Creagh when tasked with the build of a new student accommodation for University of Greenwich. The project comprises 3 multi-storey buildings housing 358 residents, all built with a precast concrete frame.

Precast concrete was the obvious choice on this project. It is speed of construction that underlines the attractiveness of using precast concrete systems as a framing material. Units are manufactured offsite ensuring the desired quality is met and leads to reduction of trades required onsite.

Creagh were responsible for the design, manufacture, delivery and installation of all members of the precast concrete frame including precast columns and beams, hollowcore flooring, walls, lift shafts and precast stairs and landings.

University of Ulster (Belfast Campus)

Creagh installed 25,000 square metres of hollowcore flooring in the new Belfast campus building at University of Ulster.  Two hundred tons of concrete beams were also installed by Creagh with the largest beam being a massive 19.5m long and 38 tonnes!

Concrete backing to UClan

University of Central Lancashire (UClan) are working on the first stage of a £200 million transformation of their Preston Campus with the successful completion of a new engineering innovation centre.

Creagh are providing a concrete backing to the £30 million building by manufacturing and installing two 30-metre-tall precast concrete cores, 6000m² of prestressed flooring and 21 sets of precast concrete stairs including one feature staircase behind its glass cladding.  By using our products on this job, construction giant BAM were able to shave weeks off the construction programme.

Creagh’s offsite construction the perfect fit for Roehampton Library

The new world-class University of Roehampton Library is a 70,000 square foot, five-storey building, housing 350,000 books and 1,060 study spaces. The build was manufactured offsite using Creaghs fast track build system and precast components.

The £34 million, state of the art building was built in the heart of Digby Stuart College, in the centre of the campus. Creagh were responsible for the design, manufacture, delivery and installation of all members of the precast architecturally exposed concrete frame with single and double height columns, plate flooring, precast beams and precast stairs. The facade is a lightweight steel frame system with weatherproof boarding and an outer precast brick-clad skin.

It is speed of construction that underlines the attractiveness of using precast concrete systems as a framing material. The amount of repetition suited the process, the project and the site. The cores were erected in five weeks and the frame took 13 weeks to install. The external cladding took another 10 weeks to complete.

Providing the solution for new student accommodation at St Andrews

This prestigious establishment chose Creagh for the first stage of their £70 million investment in student accommodation plans for the university. The first stage of the investment called for two new accommodation buildings for the campus. The new buildings called Powell Hall and Whitehorn Hall respectively created 389 new bedrooms for the university.

Creagh provided architectural concrete cladding for the buildings including feature walls with etched lettering. 695 GFRC concrete pieces were installed across the buildings. Glass Fibre Reinforced Concrete or GFRC (also known as GRC) is a type of fibre-reinforced concrete. GRC consists of high-strength glass fibres embedded in a concrete matrix. Both fibres and matrix offer a synergistic combination of properties that cannot be achieved with either of the components acting alone. The fibres provide reinforcement for the matrix, increasing its tensile strength, limiting the shrinkage and creep processes as well as eliminating curing cracking appearance.

Creagh developed a project-specific GRC mix to match both the structural performance and aesthetics requirements. This allowed the installation of floor to floor panels with 25mm concrete skin and no steel rebar. They rose to the challenge of precise filigree moulding and different casting techniques that were required for the architectural concrete cladding panels. Among the benefits of GRC: it’s reduction in thickness provides an increased cavity and/or insulation allowance and a smaller loading to the façade. All of which significatively reduce the buildings carbon footprint whilst providing the same durability and resilience as traditional concrete.

 

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FLI Carlow are the premier total service provider of engineered structural solutions to the Water, Energy, Storm Attenuation and Bespoke markets.  Our capacity to design not just the precast units, but the structure into which they integrate and the manufacturing tools used to make them has kept us at the forefront of innovation in our industry.

Semi-precast is the core of our business, a hybrid between traditional in-situ concrete and traditional precast.  Although sometimes seen as an under-developed off-site manufactured solution, the semi-precast design philosophy brings enormous improvement to cost and construction efficiency.

The semi-precast approach aims to deliver solutions fully compliant with the operational design requirement.  The ideal configuration is not adapted to prefabrication.  Whereas we will identify cost and time saving opportunities during the design development phase, we can adapt to the most precise configurations for operational accuracy.  In principle, any structure imagined in in-situ concrete can be delivered in semi-precast.  Approving Authority confidence is engendered by implementing designs which cannot be disproved by failure to comply in any respect with the specified codes and standards, whether national, international or customer specific.  We place wet concrete against hard concrete, the way it’s always been done.  The difference is that some of the concrete was manufactured elsewhere and the location of joints and interfaces are unconventional.  Regardless, the integrity of joints and interfaces remains uncompromised and verified by design.

The Benefit of Prefabrication

We complete the difficult parts of construction in our factory, under ideal conditions and under quality supervision.  Features including pipe-fittings, nibs, corbels, launder-channels, formwork attachments and stability-footings (among others) are eliminated from the site works.  Products are delivered to site on a just-in-time basis then taken from the delivery vehicle to their service position in one simple operation without fuss or temporary propping.  Small crews achieve amazing productivity by following simple steps and using well designed components and delivery systems.

Tolerance

Precast concrete units can weight in excess of 20 tonnes.  Under normal manufacturing tolerances, it could be very difficult to ensure the precision required to maintain accurate alignment and watertight fit.  The in-situ joint provides a transition between elements which ensures a complete and perfect fit (in it’s liquid phase) and a completely ‘relaxed’ structure at introduction to service.  We don’t stress pieces into alignment or position.  The design assumptions are fully realised.

Waterproofing Integrity

At every interface a scabbled surface is prepared.  In addition, a smooth dense slot is preserved for the application of hydrophilic strip.  This provides ongoing self-healing capability in service.   We use only one hydrophilic product; Denso Hydrotite.  Hydrotite is resilient to inflation prior to encasement in concrete.  It can compress against the surrounding concrete with a pressure of up to 3MPa on contact with water and has been approved by Tokyo Underground for design life up to 100 years. It is also DWI and Materials in Contact approved for potable water applications in the UK. That’s 100 years to first significant maintenance of the structure – no compromise.  Sealants used at the mechanical interfaces of traditional precast concrete tanking structures rarely have a service life in excess of 20 years.  These features are particularly relevant to storm attenuation, storage, treatment and basement applications,

Structural Continuity

Although relatively short, the in-situ joint is used to enable two-way bending of the structure.  This capacity is not available using any other precast approach.  Reinforcement lap lengths are designed on a bond-stress basis to ensure full capacity in smaller spaces.  Even the interface between the in-situ concrete stitch and the precast unit is designed for the same crack-width control as the body of the structure.  This ensures that all elements of the structure provide the minimum standard of waterproofing integrity and full compliance with concrete structures design standards.

By bending in both orthogonal directions, structures are thinner, lighter, economical, require less transport, less craneage and have a lower carbon cost.

Carbon

Our particular concrete mix design delivers very high early strength for efficient production, typically, 25 Newtons at 16 hours.  This ensures maximum safety and maximum value by extracting products daily.  We use very high concentrations of GGBS (66%) which in conjunction with other energy and carbon saving measures has reduced our carbon cost from 278kg/tonne of concrete manufactured to 182kg/tonne.  To ensure the high early strengths despite the use of GGBS we use thermal activation.  By adding mixing water at up to 80°C the disadvantage of slow strength development of GGBS is eliminated.

Sulphate Resistance

High levels of GGBS when used in conjunction with limestone cement and limestone powders (for self-compacting behaviour) produce a design chemical resistance class DC4.  That’s sulphate resistant concrete at no additional cost.

Value

The precast unit is delivered to site with projecting reinforcement often from five of it’s six faces.  All components are 3D modelled prior to manufacture and assembled in model-space prior to fabrication.  This eliminates the risk of clashing reinforcement and disruption to programme.  Projecting reinforcement leaves very few bars to be placed on site.

Typically the vertical in-situ stitches represent 30% of the volume of the perimeter and internal walls.  While precast concrete products are relatively expensive (although value-adding), the concrete used in the joints is locally sourced readymix at approximately £40 per tonne.

The formwork required is very light.  Shuttering ply facing with vertical stiffeners is locked against the structure using steel braces and MKK cone anchors.  The advantage in this low cost approach is that the formwork is torsionally flexible adapting easily to the surfaces on which they bear.  Smooth transitions and tight interfaces are achieved. Through-ties are completely eliminated.  These are often a problematic feature of conventional in-situ works.

Length of Joints

The number and length of joints in our solutions are often questioned.  Our industry sees joints as the most problematic elements of waterproof concrete construction – more joints, more risk.  The rebuttal is that it’s not the number of joints you fear, but the distance between them.  Traditional construction methods utilise joints at 6m – 10m centres.  Thermal and drying shrinkage accumulate over these lengths and are concentrated at a single interface.  The precast unit has long completed its shrinkage when placed on site therefore the shrinkage to be addressed is that occurring over only 500mm.  In addition, each interface has the benefit of a factory prepared scabble, reinforcement continuity designed to the higher standards for crack-width control and a self-healing strip at each end.  The semi-precast interface is subject to only between 5% and 10% of the movement occurring at conventional joint.  As a result, it is significantly better preforming than conventional concrete in this respect.

Rate of Construction

Semi-precast structures are typically completed in 60% to 40% of the time taken to deliver conventional structures.  This is where the value lies, both in terms of reduced preliminaries and hugely increased productivity. During the conventionally difficult construction of vertical and suspended works, equivalent productivity per person on site is ten times greater.

For more information, call us on +44 (0) 1279 423303 or email us at enquiries@flicarlow.com. You can find us on the web at the below address.

www.flicarlow.com