SpanWright Precast Concrete | Hollowcore | Flooring | Stairs

Detailing Precast – 7 top tips

Spanwright Flooring — Tue, 22 May 2012 09:52:35 +0000

Good detailing is an integral part of good construction. Where offsite construction is used for some or all aspects of the building, this becomes increasingly important. The nature of the detailing process is such that it is almost never a single individual’s task, instead someone begins the process and it evolves by iteration. Architects, Engineers, Product Suppliers, Fabricators and Construction Personnel all contribute to the final details.

In Precast Detailing, the responsibility to produce the drawing used to communicate specifics from the design team, through to manufacture and installation, is very often drafted by the precast manufacturer. This allows the details to be fine tuned by the party with the most relevant experience, namely the precaster. It is however vitally important that those who precede the precaster in the design process, have an understanding of the types of details which should be outlined and considered at the earliest stages of the design phase.


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1. REBATED OR REDUCED ENDS

What they are: These are formed at the end of the floor unit and reduce the top level of the slab over a set distance from the end of the unit. A typical detail would be reducing the depth of a 200mm deep unit by 50mm to 150mm over a distance of 150mm from the end of the unit.

Purpose: This detail typically occurs where floor units are to be placed into a steel beam or shelf angle.

Things to know: When detailing slabs into steel beams or shelf angle, slabs may be reduced but tolerance should be left for installation. A good rule of thumb is that the slabs may be reduced at the ends by ¼ of its depth but fitting still requires a tolerance of 20mm i.e. for slab depths of 200mm they may be reduced by ¼ (50mm) giving a depth of 150mm. In this situation a minimum space for installation of 150mm + 20mm = 170mm should be left. Tighter tolerances may be feasible on deeper products but this should be discussed with the precast manufacturer and installer.

2. SOLID ENDS

What they are: Units manufactured with hollow cores can have the core end filled solid for a short distance from the end.

Purpose: Solid ends can be specified for a few reasons. One reason is so as to plug the ends so as to stop air movement through the cores, plugging the cores also prevents travel of vermin through cores. The 2nd reason for filling cores is to increase the compressive load carrying capacity from live or point loads above. A 3rd reason for specifying solid ends is in cases of high shear in slender units. This will normally be checked by the precast manufacturer in his design calculations.

Things to know: While some scenarios may require solid ends to increase compressive strength even a hollow core unit is extremely strong in compression given its constituent materials. This generally makes it unnecessary to provide solid ends for this reason.

3. CAST IN LIFTERS

What they are: These are manufactured steel components with one of a number of recognised heads which can be cast into the precast unit. A variety of cast in lifting mechanisms are available from most construction accessories providers.

Purpose: Cast in lifters make it easier to position units that are awkward shapes and in complex structural arrangements. They are an alternative to lifting units with slings.

Things to know: While widespread use of cast in lifters will increase cost of a precast installation, the benefits may still outweigh the costs. Lifters may also be used strategically in only some units in order to control costs. It is important to coordinate the use of cast in lifters on site so that units such as stairs and floors, which may come from different suppliers, can still use the same lifting equipment.

4. RIPPED SLABS

What they are: They are precast concrete slabs of the same production as full width units and are cut in the factory to produce a narrower unit.

Purpose: Ripped Slabs are used to fill out bays which are not the right width to take another full width slab. They are also occasionally specified where slabs side bear onto the structure and a square edge is required for continuing the build.

Things to know: Normally slabs may only be ripped (or cut) along the hollow core. Because of the production limitations on rip widths it is normal to expect a tolerance up to 100mm when filling out bays with slabs.

5. SOLID CORES

What they are: These are machine formed cores that are filled with concrete post manufacture while the cast slab is in a semi set state.

Purpose: Solid cores provide a solid section into which fittings for wind posts can be post fixed on site. They also prevent collapse of the hollow units under high point or line loads. It is important to specify solid cores in locations where the edge of units are expected to carry a point load such as suspending a flight of stairs on an angle support

Things to know: When visually inspecting hollow core units, solid ends in a slab may give the impression of the cores being solid throughout the slabs. A core should never be assumed to be solid unless it has been specified as such on manufacturer’s drawings and/or trial bored onsite. It is possible that in wet cast slabs a void former in the slabs provides a core in an otherwise apparently solid unit.

6. OPEN CORE / CONTINUITY SLOTS

What they are: These are usually 2 No hollow cores evenly spaced across the slab with the top flange of the slab removed over the width of the core and a distance of apx.600mm at the end of the unit.

Purpose: Open cores in hollow core units are created where there is a requirement to provide a structural connection with adjacent units or another part of the structure across the bearing. The open core is formed to receive a steel bar and infill concrete during the grouting process.

Things to know: Considerable planning must be given when considering continuity slots and tie steel. Where continuity steel is to be fixed to the structure and bent into
the open core it is advisable to post position the continuity bars in line with open core positions. Where the tie steel is across a bearing from open core to open core, it is necessary to align bays so that open cores consistently fall opposite each other.

7. OPENINGS & NOTCHES

What they are: These are holes created in the floor area by means of cutting, coring or specialist casting.

Purpose: Openings and Notches are used where precast units conflict with other construction items such as: Plumbing, Electrics and Steel Posts. Most precast units can tolerate some cutting and coring to accommodate services etc. but this gets more limited as units approach the limit of their design.

Things to know: Openings and Notches should be considered at the design stage, and where they are required to be post formed on site advice should be sought from the precast designer. It is important when considering openings in units to allow for temporary state impacts such as handling and installation on the units integrity. Small nibs of concrete and multiple perforations in the same zone are not generally feasible. In the case of the later, it is often a better idea to completely omit an area of floor and introduce a steel support hanger.

Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

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For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Project – Pig Fattening House, Northallerton

Spanwright Flooring — Fri, 20 Apr 2012 15:11:16 +0000

ABOUT THE PROJECT

SpanWright UK were contracted to supply and fit Pig Slats and Pig Beams to Morton Grange Farm located centrally between the Yorkshire Moors and the Yorkshire Dales. This AR Sanderson Fattening House would be considered a standard size, catering for circa 1000 pigs. Each batch of pigs is fattened for a 12 – 14 week period with approximately four batches per annum going through the system.

PROJECT CHALLENGES

Construction of the Pig Fattening House was managed in three stages. Coordinated between Client, Shuttering Contractor and SpanWright UK was required in order to ensure structural integrity. Unit design in turn dictated shuttering requirements in order to provide support for the slats, beams and roof of the building. SpanWright UK , in liaison with shuttering contractor, designed positioning of concrete pillars for portal roof support. This also enabled uniform sizing of slats used which in turn negated cutting of slats to fit.

Once shuttering was nearing completion delivery and fitting of Pig Slats and Beams could commence, as the Fattening Unit was required for completion on a fixed timeframe. Delivery and fitting of pig slats and pig beams was completed within one week.




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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Tesco Express – Pontypridd, South Wales

Spanwright Flooring — Tue, 13 Mar 2012 10:05:57 +0000

AM Contractors Ltd are Construction and Civil Engineering Contractors. They specialise in commercial and domestic developments in the South Wales area. The original business, set up in 1999, focused on Civil Engineering, Construction, Demolition and Plant Hire. Having developed the construction arm of the business in 2001, they now have a reputation for providing a competitive, quality service with an impressive track record of contracts for blue chip companies.

ABOUT THE PROJECT

SpanWright UK were selected by AM Contractors to supply and fit at first floor level on this TESCO, Alexandra Terrace project. The retail giant employing over 492,000 worldwide, including 2715 stores in the UK (tescoplc.com), opened the Express store in June 2011. The mixed use retail and residential project on a redeveloped site includes apartments at first floor level.

PROJECT CHALLENGES

The Architectural Design of the TESCO building specified a Timber Frame (TF) for the apartments on the upper level. An external split level section of the building acting externally as a walking area required a slab to accommodate roof loadings. SpanWright UK, accommodating the loadings for the TF, incorporated heavy strand steel pattern in planks for the central bays of the building in manufacture. Prestressed planks were prepared with rebated ends for fitting into a steel frame to support the TF. Prestressed planks on the perimeter of the building were manufactured to include solid ends in order to affix the timber frame. A Flat Plate (FP) option was utilised as the best option for the building section requiring roof loadings. 100mm Solid FP placed to a fall with 75mm non structural screed produced inherent high density in the FP which in this case acted as a noise barrier. Internal ceiling & services loadings and external snow and paving slabs requirements were accommodated.




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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Aldi Store, Rotherham – PDR Construction

Spanwright Flooring — Tue, 21 Feb 2012 09:58:13 +0000

PDR Construction Ltd based in Hessle, Hull is one of the largest independent construction companies in the north of England. PDR work on delivering cutting edge solutions across a variety of sectors, including Automotive, Industrial, Blue Light, Retail and Non Food Retail. PDR- work in partnership with their clients, to respond to their varied needs for new build, renovation or fit out contracts. PDR- work within short lead times and guaranteed completion dates adhering to ‘business as usual’ where required.

ABOUT THE PROJECT

SpanWright UK were subcontracted to supply and fit 250mm prestressed flooring planks at the PDR – Eastwood, Rotherham site for German discount retailer Aldi Stores Ltd. One of many high profile retail sector clients, the £1.2 million Fitzwilliam Road store was the 12th Aldi project for PDR - proving their track record of delivering successful projects for the supermarket retailer.

PROJECT CHALLENGES

SpanWright UK had to work within a pre erected steel framed structure to place planks at ground floor level. A split level floor area to accommodate cold storage insulation requirements had to be incorporated. Prestressed flooring planks were pre notched, on manufacture, in order to slot into the steel frame and cores formed pre delivery to accommodate service openings. SpanWright UK fitted at ground floor level, dropping planks at a slightly lower level for the cold storage area, to allow extra insulation to be fitted, thus finishing the complete floor area on the same level. SpanWright UK prestressed flooring is a cost effective time saving construction product. Using 100Tn craneage the precast flooring planks, once fitted, also provided a safe working platform for following on services and trades. Site Manager Shaun Ruane acknowledged the professionalism of the SpanWright UK Operatives on site.


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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.
Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

House Extension, Chiddingfold – SpanWright UK

Spanwright Flooring — Thu, 09 Feb 2012 11:56:18 +0000

Castle Eaton Construction Ltd is a medium sized building company specialising in residential building works. Utilising their specialist subcontractors’ expertise ensures projects are completed quickly and to a high standard. Subcontractors work in sequence to conclude their individual part of the project and in such a way as to help the following trades.

ABOUT THE PROJECT

Castle Eaton Ltd appointed SpanWright UK to supply and fit at first floor level to this house extension in Godalming, Surrey. The project, on a mature site
accessed from the private residential Pickhurst Road, Chiddingfold, demanded a quick turnaround for construction. SpanWright UK specified 200mm prestressed flooring as the most suitable product to accommodate engineering and architectural construction requirements.

PROJECT CHALLENGES

Castle Eaton placed the order for Hazelbridge House in the 1st week of May and required delivery and fitting for end of that month. SpanWright UK’s technical department working with Client appointed Engineer and Architect worked proactively to conclude SpanWright construction layout drawings for approval. The layout reflected that the units were designed to take account of roof loadings over and above standard load bearing requirements. Drawing approval from client engineering was confirmed for the following week. Prestressed flooring was manufactured for delivery as requested by client. The consignment was delivered and fitted in one day using air mattress system for fall arrest around trailer for safe offloading and fitting with on site craneage.

TESTIMONIAL

SpanWright UK prestressed planks are manufactured on heated steel casting beds to achieve high standard finish to type A Clause 6.11.3 of BS 8110. Service openings up to 75mm diameter can be drilled on site. Larger openings are achievable in production –pending design approval. Planks have a minimum fire resistance of 1 hour which can be further enhanced at design stage if required. SpanWright prestressed flooring, delivered in sequence, provides a safe and speedy working platform. In house fitting crews can leave slabs finished with grout connections filled or, in the case of composite options, structural toppings can be placed over the entire area subsequent to installation by SpanWright UK. In most cases formwork and propping is not required allowing open spaces above and below to facilitate following trades.

Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

SpanWright UK work with Tolent Construction on Promenades Shopping Centre, Bridlington

Spanwright Flooring — Thu, 26 Jan 2012 16:30:03 +0000

ABOUT THE PROJECT

The Promenades is Bridlington’s largest covered Shopping Centre. Located in the heart of the Town Centre its recent re development and extension has seen an increase in footfall from 80,000 to 120,000 per week. SpanWright UK supplied 200mm prestressed planks to the revamp for Tolent (Central East), one of several projects SpanWright UK has supplied for Tolent Construction Ltd in 2011.

PROJECT CHALLENGES

The Promenades -being at the heart of retail in Bridlington- stayed in operation for the duration of the works to extend and reconfigure the shopping centre. Three new retail units were formed along with new high quality public toilet facilities. SpanWright UK’s Design Team, working with Tolent, designed 200mm Prestressed Planks to accommodate architectural design features and shopping centre loadings and fitting schedules. Long spans were required to reach steel frame support points. Planks were splay cut along one complete side of the structure as per design feature.

Lifting Eyes were cast into units on manufacture to accommodate Client fitting made easier due to shape and spans of the planks. The Prestressed Plank design was optimised for the expected increase in footfall and retail equipment loadings in the 25+ Unit Shopping Centre.


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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Spanwright UK – Tolent Construction – BskyB Studios

Spanwright Flooring — Thu, 26 Jan 2012 15:51:33 +0000

ABOUT THE PROJECT

SpanWright UK were appointed by Tolent to work on the construction of the new Sky Studios Complex at Osterley West London. The plant incorporates the UK and Ireland’s first biomass Combined Cooling Heating and Power system. Costing £250 million the complex completed in Q4 2011. SpanWright UK supplied precast concrete stairs and 250mm prestressed planks at first and second floor levels to the 16,000m2 energy centre on this (CCHP) project.

The plant is part of the government supported FiT scheme (feed-in tariff ), commercial companies working to develop renewable on-site power –surplus to be fed into the national grid, and is expected to reduce the building’s carbon footprint by at least 20%. The project is expected to achieve an ‘excellent’ rating under the Building Research Establishment Environmental Assessment Model (BREEAM) a standard demonstrating progress towards corporate and organizational environmental objectives.

PROJECT CHALLENGES

Spanwright UK again had to demonstrate the flexibility in design of planks, accommodating sufficient loadings and design requirements of the Clearpower designed CCHP system. SpanWright UK 250mm prestressed planks had additional reinforcement steel strand incorporated to withstand various equipment loadings and sizes including a thermal furnace and a turbo generator. Open cores and solid ends ensured continuity steel to avoid crushing and also reinforcing complete flooring structures. Some planks had to be designed to fit around heavy plant which spanned flooring levels. Lifting points to withstand weights of 3 Tonne were incorporated to the underside of some planks in order that a pully system may be used to lift equipment during servicing. SpanWright UK precast concrete stairs were also installed using 5Tn Halfen Deha lifters, providing a safe means of accessing multiple floors during construction.

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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Steps to access Waitrose

Spanwright Flooring — Wed, 07 Dec 2011 16:18:24 +0000

ABOUT THE PROJECT

Waitrose, food division of the John Lewis Partnership, is an upmarket chain of supermarkets in the UK with a Royal Warrant to supply Queen Elizabeth 11 and Prince Charles. The Wimbledon, Alexandra Road development, following on from Waitrose Mini Supermarket in the town centre, had its official opening on 27 July. Waitrose is the 6th largest grocery retailer in the UK with 255 branches nationwide. SpanWright UK were appointed by RG Carter Projects Ltd for our Precast Concrete Stairs design to complete another step in the Waitrose project.

PROJECT CHALLENGES

Following on from their involvement in the Waitrose Westfield Flagship Store located in White City, London – the largest shopping complex in Europe, RG Carter strove to maintain their high standards of architectural and structural design and finish in the Wimbledon project.
SpanWright UK, modified existing product design, manufactured 1600mm wide steps with brushed finish in order for RG Carter to have the surface finished in Terrazzo on site. Sockets and tie bars were used to connect flights and landings maintaining continuity reinforcement for a structure expected to support the volume of footfall required to be part of doubling Waitrose revenues to £8bn by 2016. SpanWright delivered stairs featuring the Halfen Deha system in order for RG Carter to lift and fit stairs in accordance with their construction programme.




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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

The University of Northampton – Cottesbrooke Building Extension

Spanwright Flooring — Thu, 03 Nov 2011 09:15:40 +0000

ABOUT THE PROJECT

The Cottesbrooke Building extension was yet another opportunity for SpanWright UK to exercise our flexibility on product design and fitting in collaboration with The General Building Contractor on site, Stepnell Ltd. The work involved the construction of a two storey extension which wrapped around the Eastern end of the existing Cottesbrooke Building
on the Park Campus.

PROJECT CHALLENGES

A bespoke curved slab was designed to support large curved frontage including windows on the new extension and was manufactured to accommodate steel wind columns. Additional slabs had to be splayed to suit architectural design and all slabs notched to slot into a steel frame which was already in place.
SpanWright UK successfully supplied and fitted at first floor level in one visit.


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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk

Aggregate Industries UK ltd T/A Eden UK Network Rail – Route F – Thameside

Spanwright Flooring — Wed, 26 Oct 2011 11:50:21 +0000

ABOUT THE PROJECT

The Aggregate Industries Group offers an extensive range of products and services to the construction industry and is a major supplier to all sectors of UK infrastructure. This includes Rail Specific products and expertise through their various subsidiaries. SpanWright UK had the opportunity here to show the flexible nature in our existing precast and prestressed flooring products and bring a timely and best value solution for Aggregate Industries in the ongoing Network Rail £34 billion development and improvements programme.

PROJECT CHALLENGES

The Tilbury Loop on Route F Network Rail is one of the busiest passenger and freight sections of NR Thameside. The average footfall is 30,000 per day and it is envisaged with continuous developments train numbers will increase to 30 per day by 2030. SpanWright UK’s contribution of the structural decking for railway platforms in the form of existing 215mm and 250mm deep flooring planks plays an integral role in the provision of the infrastructure that is going to last into future generations.
SpanWright UK were initially contracted as supply only contractors for stocking at Stanford–le–Hope. The original order of 468 m2 was delivered to schedule within a remarkably short lead time of less than 3 weeks. An additional 2387m2 following on order was then received for Purfleet and furnished via a rolling schedule to Purfleet, Rainham, Dagenham & Pitsea Stations to keep the works project on track.

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Spanwright is a leading supplier of precast concrete flooring and concrete stairs throughout the UK.

Products manufactured include:

For further information on spanwright call us on 01793 441474 or email our sales team at sales@spanwright.co.uk