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Precast Concrete in Buildings

A GUIDE TO DESIGN AND CONSTRUCTION

Precast Concrete in Buildings

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Contents

1 Benefits of Precast Concrete 4 Precast Concrete Buildings 6 Precast Concrete Floors 8 Precast Concrete Elements 10 Architectural Cladding Panels 12 Joints and Connections 13 Production 14 Site Erection 15 Maximising the Benefits of Precast Concrete 16 Case Studies 17 References

INTRODUCTION

The use of precast concrete elements is well established as a construction method throughout the world and provides solutions for a great variety and complexity of layouts, shapes and façade treatments.

Precast concrete can be incorporated into every building type. Whether the building has a regular or an irregular shape, the entire structure or elements of that building, such as frame, floors, walls, stairs or balconies, can all be precast. Precast construction is virtually unlimited in its application and is suitable for single and multi-storey construction. In fact, precast building elements should be considered as an option for every construction project. Bespoke designs can be achieved using standard precast components, which need not imply a modular appearance. Precast elements, including floors, stairs and wall panels combine seamlessly with non-precast elements to produce free-flowing spaces. Curved precast panels with a wide range of attractive and durable finishes can meet the most challenging of design requirements. An error to be avoided is to take an `all precast or no precast approach' to design. The key issue for designers is to identify which construction method, or mix of construction methods and materials, is most appropriate for the specific requirements of the building. The most economical solution might well consist of a mix of cast in-situ and factory produced, precast units. Preliminary structural investigation may identify solutions such as beams and floor slabs fabricated off-site being erected on cast in situ columns. These structural elements are then integrated as a composite structure when the in situ structural topping is placed. Thorough consideration of construction options at an early design stage is critical to optimise speed of build, structural performance and delivery of the most economical frame package for each project. Efficient structures are just one way of providing a sustainable building. The precast concrete industry has recognised the importance of sustainability and is funding a research programme to deliver a sustainable strategy for manufacturing which complements the progress that is already being made. Key issues are being targeted including: · Health and safety · Employment · Supply chain · Social/community · Energy · Waste · Resources Further up to date information can be found at www.sustainableprecast.com

More London hotel, London. This 250-room building was constructed using twinwall construction.

Courtesy of John Doyle Construction.

Cover pictures: Main: One Coleman Street, London.

Courtesy of Decomo.

Inset top: Malmaison Hotel, Liverpool.

Courtesy of Buchan Concrete Solutions.

Inset bottom: Precast beams at London School of Economics. Courtesy of Thorp Precast.

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BENEFITS OF PRECAST CONCRETE

The advantages of factory production combined with the inherent benefits of concrete provide compelling reasons to use precast concrete. In assessing suitability, designers and cost consultants should consider the benefits discussed in this section: · Cost and programme · Performance in use · Quality · Design · Pre-manufacture · Sustainability

Buildability

Precast elements are designed by specialists with experience in ensuring that the structure can be erected quickly and efficiently.

Whole building costs

The Concrete Centre has commissioned independent cost model studies for various types of buildings which have demonstrated that the choice of structural frame has cost implications for a number of other elements of the building. For example, a concrete stability core also provides a division wall between the circulation space and the useable space. A stability system comprising steel members requires additional partitioning to create the division wall, which increases the comparative cost.

Cost and Programme

Economy

Using precast elements reduces requirements for formwork and access scaffolding, this saves cost through reduced resources and by shortening the programme. There is less reliance on wet trades, which can be delayed by unfavourable weather conditions. There are also benefits in using precast elements for specific areas of the building such as stairs, where safe access is immediately available once installed.

Whole life value

Frame choice and design can have a surprisingly influential role in the performance of the final structure, and importantly, also influence people using the building. Therefore, although concrete can often be cheaper, cost alone should not dictate frame choice. Many issues should be considered when choosing the optimum structural solution and frame material that give best value for the construction and operational stages. Inherent benefits ­ fire resistance, sound insulation and fabric energy storage (thermal mass) ­ mean that concrete buildings tend to have lower operating costs and lower maintenance requirements. This is also particularly important when considering the environmental performance of a building.

To obtain best value, designers should consider early involvement of the precast concrete manufacturer who will have considerable expertise that can reduce cost and maximise value when harnessed early in the design process.

Speed of Construction

Speed of construction and tight construction programmes are primary considerations in most building projects. To maximise the speed of construction with precast elements, two critical factors should be taken into consideration: · The building layout should be designed to maximise repetition of precast units. · Construction details should be designed to maximise the number of standardised components. Installation times for precast units vary with each project, but indicative rates of installation (based on one erection crew) are shown in Table 1.

The Woodview development in Birmingham utilised precast crosswall and hollowcore floors to achieve quick, economical and high-quality housing. Courtesy of Bison Concrete.

Table 1: Indicative installation (based on one erection crew)

TYPE OF UNITS Single storey columns Spine or edge beams Wall panels Floor units Stairs or landings NO OF UNITS 12 to 14 per day 12 to 15 per day 12 to 16 per day (up to 150m2. per day) 250 to 350m2. per day 12 to 15 per day

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Precast concrete can meet the design requirements for buildings: · High quality finishes · Fire resistance · Long clear spans · Long life · Acoustic performance · Air-tightness · Vibration resistance · Sustainability performance

Performance in use

Inherent fire resistance

Concrete has inherent fire resistance, which is present during all construction phases, and is achieved without the application of additional treatments. It is also maintenance free. Concrete has the best European fire rating possible because it does not burn and has low heat conductance. Further information can be found in Concrete and Fire [1] by The Concrete Centre.

Quality

Off-site production provides a high quality product for the following reasons:

Accuracy

Precast elements are cast to close tolerances, and checked in the factory before delivery to site. Quality control systems, a consistent well trained workforce, and widespread use of self-compacting concrete ensure a high standard of workmanship.

Acoustics

Concrete's qualities make it good for acoustics ­ meaning additional finishes can be minimised. Precast components can meet the highest standards for resistance to sound transmission. Buildings employing precast components are included in the Robust Details accepted by Robust Details Ltd under Part E of the Building Regulations. Further information can be found in Concrete and Sound Insulation [2] by The Concrete Centre.

High quality finishes

High quality finishes are generally achieved through the use of robust, purpose made formwork and dedicated concrete mix designs in a factory environment. Sample finishes can be approved by the client as a benchmark for the project requirements. Acceptability of finishes can be confirmed prior to leaving the factory. A wide choice of precast concrete cladding finishes and facings is available, including: · Surface retarding and wash-off · Rubbing · Abrasive blasting · Bush hammering · Mechanical grinding and polishing · Acid etching More information on architectural finishes can be found on pages 10 to 11.

Air-tightness

Part L of the Building Regulations requires precompletion pressure testing. A building failing these tests will have to undergo a time-consuming joints and interfaces inspection process, resealing where necessary. Precast cladding improves air-tightness because the large units reduce the number of joints. These joints are also easier to seal because the edges of the units are flat surfaces.

Vibration control

For concrete buildings, vibration criteria for most uses are covered without any change to the normal design. For some uses, such as laboratories or hospitals, additional measures may be needed, but these are significantly less than for other materials. A study by Pavic et al[3] demonstrated that the vibration criteria for a laboratory with a grid of 6.6m x 7.3m could be met with a 400mm deep hollowcore unit and screed. The less onerous hospital vibration criteria could be met with a shallower unit. Information on how to design structures to control vibration can be found in The Concrete Centre's publication A Design Guide for the Footfall Induced Vibration of Structures[4].

Consistency of concrete supply

For visual concrete, consistency of colour and texture is important. Precast factories have dedicated concrete supplies ensuring consistency of supply and giving greater control of the constituent materials used.

Controlled environment

Production takes place in an enclosed space, giving protection from the weather, allowing manufacture to occur in all conditions.

Precast concrete balcony, complete with finishes, services, fixings and connections, ready to be placed on-site. Courtesy of Marble Mosaic.

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Design

Long clear spans

Reducing the number of columns is often important in developments such as offices, sports stadia and car parks. Prestressing the concrete can deliver these longer spans or shallower construction depths.

Pre-manufacture

A reliable service

Precast concrete manufacturers offer a complete service from design through manufacture to installation. The production facilities are in an enclosed environment which ensures continuity of prefabrication. The facilities are managed to maximise output and meet programme requirement. Reduction of noise is a further benefit, as precast elements can be erected quietly on-site, minimising disruption to neighbours.

Sustainability

The environmental, social and economic impacts of developments are increasingly being considered during initial design. Concrete has many sustainable benefits during both the construction and operation of a building.

Proven designs and methodologies

Precast construction incorporates proven technologies and methodologies which have been developed over many years.

Thermal mass/fabric energy storage

A concrete structure has a high thermal mass. Exposed concrete, typically floor soffits, allows fabric energy storage (FES) to regulate temperature swings. This can reduce initial plant costs and ongoing operational costs, while converting plant space to usable space. With the outlook of increasingly hot summers, it makes sense to choose a material that reduces the requirement for energy intensive, high maintenance air-conditioning. Precast with its high quality concrete finish is well suited to providing useful thermal mass on exposed surfaces. Further information can be found in publications from The Concrete Centre[5,6,7].

Durable

Concrete designed and built to the requirements of BS 8500 will have a working life of 50 years, or 100 years if required. Also, as concrete is such a hard wearing material, it can be utilised in tough environments such as school corridors.

Health & Safety

Once precast floors are installed, they provide a safe working platform for site operatives. Simultaneous installation of precast stairs offers safe and easy access between floors once handrails have been installed. Off-site manufacture generally reduces the level of activity on site and this can enhance safety. The Architectural Cladding Association, Precast Flooring Federation and Structural Precast Association have each published Codes of Practice for Safe Installation of their respective products.

Mouldable

Concrete can be formed into any shape. The only limit is the designer's imagination. Repetition of elements can make even complex shapes affordable for projects which are cost-driven.

Locally sourced material

The vast majority of precast concrete used in the UK is manufactured in the UK. All the constituents of concrete are usually locally sourced: · 99.9% of aggregates used in the UK are sourced in the UK (80% are used within 30 miles of extraction).

The Lawn Building, Paddington Station, London. Precast concrete was used to give a high-quality finish, enabling the thermal mass of concrete to be exposed. Courtesy of Trent Concrete.

· 90% of Ordinary Portland Cement is produced in the UK (there are cement kilns throughout the UK). · 100% of UK sourced reinforcement is produced from UK scrap steel.

Less wastage

Strict control of materials and efficient machine processes in a factory environment minimises wastage and therefore costs. A recent research report by WRAP [9] concluded that waste sent to landfill is less than 1% of the total material weight.

Other sustainable benefits

Concrete is durable, frequently allowing building reuse, rather than replacement. If the building is to be demolished, precast units are increasingly e-tagged: an electronic chip is embedded in the unit and contains the design information. This will allow the unit to be reused in the future. Concrete that cannot be reused is 100% recyclable, as are reinforcing bars. Precasting reduces the noise and waste from the construction site to the factory where it is easier to manage. Further information on the sustainability credentials of concrete can be found in the publication Sustainable Concrete [9].

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PRECAST CONCRETE BUILDINGS

Car Park Frame and Deck

There are three frequently used forms of precast building construction in the UK: · Car park frame and deck (floors) · Crosswall construction · Volumetric construction In addition, precast elements may be combined with in-situ concrete to deliver `hybrid' construction. Further details are given on page 5. Precast concrete frames can also be used for: · Single-storey industrial sheds · Multi-storey offices · Public buildings Some examples are given in the case studies on page 16. Precast columns and beams with precast decks are commonly used for car parks. They can be independent, free standing or form part of a mixed development. Car parks tend towards a standard bay size of 15.6m x 7.2m, the longer dimension being used to avoid columns between car parking spaces. Prestressed precast deck units are ideal for the long spans and two solutions are regularly used: · 400mm thick hollowcore units · 600mm deep double tee units The latter can be combined with double tee ramps which can span up to 16m. A number of options are available for spanning the shorter distance, including: · Precast beams · In-situ beams (i.e. hybrid concrete construction) · Precast `spandrel' panels Spandrel panels are combined beam and wall panel units. Spandrel panels also act as internal vehicle barriers or as external vehicle barriers when used at the perimeter of the structure.

Crosswall Construction

Crosswall construction, using precast floors and load bearing walls, is normally associated with multistorey buildings. This type of construction is ideal for buildings of a cellular nature, for example hotels, student accommodation, housing and apartments. In crosswall multi-storey structures the walls are designed as the means of primary support. Longitudinal stability is achieved by external wall panels and/or diaphragm action involving the floors and roof, connected back to lift cores or staircases, which may also be formed by precast wall panels or shaft units. The system provides a structurally efficient building with main division walls offering a high degree of sound insulation between adjacent dwellings or rooms. Crosswall construction has all the advantages of precast concrete construction with the following highlights being particularly beneficial: · High quality finishes ­ often it is only necessary to have a skim coat on the ceilings and walls. · Thermal mass ­ there is a significant thermal mass which is easy to utilise because of the minimal finishes. · Bathroom pods ­ these can be easily integrated into the structure and be fully fitted out. · Acoustic performance ­ tests have shown that crosswall exceeds the Part E acoustic requirements by a significant margin. The cost savings from these and other benefits, such as inherent fire resistance, should be fully considered when comparing the costs with alternative structures. Further information on crosswall construction can be found in a guide from The Concrete Centre[10].

Churchill Square car park, Brighton. Prestressed concrete double tees with curved soffits were used to give long clear spans supported by circular and elliptical columns. Courtesy of Tarmac.

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Volumetric Construction

Projects such as prison cell blocks can benefit from modular precast construction which offers particular benefits, including: · Robustness · Off-site fitting out · Rapid assembly on-site · Independence from extremes of weather ­ project certainty The on-site construction phase is substantially reduced by using concrete modules cast as five-sided boxes (usually four walls plus a roof) in purpose-made steel moulds. The modules will generally be delivered to site on low-loaders, with the ground floor units being erected onto a prepared ground floor slab. The subsequent units are then successively erected onto the roofs of the units below. Units are generally fitted out at the factory with windows, vents, bathroom and other fittings, plus plumbing and electrical fixtures and fittings. A major benefit of the factory production process is that it can be carried out largely unaffected by weather extremes. Once on-site, in addition to a reduced construction period, there will also be a substantial reduction in site labour requirements.

Hybrid Concrete Construction

The combination of precast concrete with in-situ concrete can be seen to make best use of the advantages of each, which are given in Table 2. Added to the inherent benefits of thermal mass, durability and good fire resistance, hybrid concrete construction can provide straightforward and quickly-built structures that are of high quality and extremely economic. The use of precast concrete for the major part of hybrid concrete structures will reduce the overall construction time, the amount of traditional formwork which has to be used and the number of operatives engaged in wet-trades on-site. Safe working platforms are created by the adoption of precast floor systems, enhancing the level of safety on-site. Information on the various precast elements that can be used for hybrid concrete construction is given on the following pages. More details of the options, design and procurement of hybrid concrete construction can be found in a number of publications from The Concrete Centre[11,12,13].

Table 2: Benefits of Hybrid Concrete Construction

PRECAST Quality Excellent Finish Consistency Speed of build Accuracy IN SITU Economy Flexibility/versatility Bespoke situations Continuity Robustness

Toyota (UK) headquarters. Precast concrete, combined with in-situ concrete, was used to give high-quality office space. Courtesy of Trent Concrete.

A concrete bathroom pod being lifted into crosswall student accommodation at the University of the West of England, Bristol. Courtesy of Buchan.

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PRECAST CONCRETE FLOORS

Hollowcore Floors

Hollowcore slabs derive their name from the voids or cores which run through the units. The cores can function as service ducts and significantly reduce the self-weight of the slabs, maximising structural efficiency. The cores also have a benefit in sustainability terms in reducing the volume of material used. Units are generally available in standard 1200mm widths and in depths from 110mm to 400mm. There is total freedom in length of units and splays and notches can readily be accommodated. Hollowcore slabs have excellent span capabilities, achieving a capacity of 2.5 kN/m2 over a 16m span. The long-span capability is ideal for offices, retail or car park developments. Units are installed with or without a structural screed, depending on requirements. Slabs arrive on-site with a smooth pre-finished soffit. In car parks and other open structures, pre-finished soffits offer a maintenance free solution. Prestressed units will have an upward camber dependent upon the span, level of prestress, etc. This will be reduced when screeds/toppings or other dead loads are applied. Hollowcore units with reinforcement are also available, generally 225mm deep and 1200mm wide. They have a shorter span capability but do not exhibit upward camber. They can also be made available with an integral layer of expanded polystyrene on the soffit to provide insulation for ground floor situations.

Solid Prestressed Floors

Solid prestressed units, 75mm or 100mm thick, are often produced on the same prestressing beds as hollowcore floors. These units are designed to be used compositely with an in-situ concrete structural topping between 75mm and 150mm thick.

Coffered Floor Units

The increasing importance of reducing operational or `energy in use' and the need to expose the high thermal mass of soffits has led to the development of coffered floor units of various shapes. Being individual, there is usually a cost premium, but with careful planning the moulds can be reused many times, making them more cost effective. The units are designed to be aesthetically pleasing and can carry conduits for services.

Termodeck

Termodeck is a specialist application of hollowcore slabs. The voids within the slab are used as part of the ventilation system. Air is circulated through the voids before being discharged into the room. This enables the benefits of thermal mass to be maximised through active measures in addition to the passive benefits.

Span to depth graphs for various precast elements

a) Hollowcore a) Hollowcore 400 Hollowcore a) a) 400 Hollowcore 350 400 Slab depth, depth, mm Slab mm Slab mm Slab depth,depth, mm 300 350 250 300 350 400 Slab depth, depth, mm Slab mm 300 350 250 300 200 250 150 200

b) Lattice Latticeslabs slabs b) girder girder 350 b) Lattice girder slabs slabs 350 b) Lattice girder 350 300 Slab mm Slab depth,depth, mm 300 250 350 300 300 250 250 200 200 150 150 100 4.0 3.0 3.0 4.0 5.0 4.0 4.0 5.0 6.0 5.0 5.0 6.0 7.0 6.0 6.0 7.0 9.0 8.0 9.0 7.0 8.0 Span, mSpan, m 9.0 7.0 8.0 9.0 8.0 Span, mSpan, m

200 250 150 200

250 200 200 150 150 100 100

100 1504

100 150 6 7 8 9 10 11 12 13 14 15 16 5 4 5 6 7 8 9 10 11 12 13 14 15 16 Span, mSpan, m 100 100 10 11 12 13 14 15 16 4 5 46 57 68 79 8 9 10 11 12 13 14 15 16 Span, mSpan, m c) Beam and block block c) Beam and

3.0 3.0

100

d) DoubleDouble Tee unit d) Tee unit d) Tee unit d) Double Double Tee unit 800 Slab depth, depth, mm Slab mm Slab mm Slab depth,depth, mm 700 800 600 700 800 700 800 600 700 500 600 400 500

350c) Beam and block block 350 c) Beam and 350 300 Slab depth, depth, mm Slab mm Slab mm Slab depth,depth, mm 300 250 350 300 300 250 250 200 200 150 150 100 100 4 3 3 4 45 45 56 56 67 67 78 78 9 89 Span, mSpan, m 9 89 Span, mSpan, m

Key

IL= 2.5 kN/m2 IL= 5.0 kN/m2 IL= 7.5 kN/m2 IL= 10.0 kN/m2

250 200 200 150 150 100 100

500 600 400 500

3 3

300 400 250 6 300 250 6

300 400 250 17 7 8 9 10 11 12 13 14 15 16 15 18 18 300 6 7 8 9 10 11 12 13 14 Span,16 17 mSpan, m 250 7 68 79 8 9 10 11 12 13 14 15 16 17 18 10 11 12 13 14 15 16 17 18 Span, mSpan, m

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Lattice Girder Slabs

Lattice girder units comprise a thin precast concrete `biscuit' into which a lattice girder made of steel reinforcement is cast. The units are usually 2400mm wide and can be supported with in-situ or precast concrete beams. Once in position, reinforcement is fixed to the top of the lattice girder and an in-situ concrete topping is poured which acts compositely with the precast concrete. The overall floor depth is generally in the range 150mm to 300mm. The floor slab can be designed to act continuously across several spans. Void formers can be introduced in the form of polystyrene blocks or spheres made from recycled plastics. Different systems are available from various manufacturers. The void formers reduce the quantity of concrete used and also the self-weight of the slab.

Double-Tee Floor Units

Double-tee floor units are ribbed precast prestressed concrete units. They can be procured in a variety of depths from 300mm to 800mm and even beyond but the most common unit is 600mm deep as this conveniently carries office loading over 12m and car park loading up to 16m. The top flange is usually 50mm or 60mm deep and the ribs taper from a minimum of 140mm at the base, widening upwards towards the underside of the top flange, the taper of 1 in 20 each side allowing for easy lifting out of a fixed mould. Double-tee floor units are produced in standard widths of 2400mm. They offer greater structural capacity at longer spans than hollowcore or lattice girder but often require a deeper floor zone. The ribbed soffit profile can provide improved aesthetics in many situations. Account should be taken of the camber of the units, particularly for longer spans.

Easy to install beam and block flooring.

Courtesy of Cemex.

Beam and Block Flooring

Beam and block flooring consists of extruded or wet-cast prestressed beams between 150mm and 225mm deep, together with blocks of various types. These may be purpose-made blocks with rebates to suit the shape of the beams (`tray blocks') or may be standard concrete masonry blocks which have been tested and certified for use in floors. Also commonly used are specially shaped extruded or expanded polystyrene blocks which provide a high degree of insulation for ground floors. The use of beam and block is well established in ground floors, particularly for housing, with domestic and commercial upper floor use a growing market sector. The standard spacing of the beams is to suit the length of masonry walling blocks (440mm) interspersed with the beams. This may be reduced to 215mm when the walling blocks are turned through 90º. Beams may be placed in pairs to accommodate loading from partitions and in the extreme, under heavy loading or for long spans or other line loads, beams may be placed abutting each other over the whole floor.

Double-tee floor units. Courtesy of Tarmac.

Hollowcore units quickly provide a safe working platform.

Courtesy of Hanson.

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PRECAST CONCRETE ELEMENTS

Salvation Army headquarters, London, makes use of precast concrete for exposed structural elements.

Beams

Precasting elements in concrete can be used to speed up construction, provide high quality finishes or reduce the costs for specific elements of the frame. The biggest benefits usually come from repetition. Particular elements that are regularly used in combination with other forms of construction are: · Columns - for a quality finish or to reduce programme. · Stairs - for a quality finish or for safety. · Balconies - to allow pre-assembly in a safe environment. Precast concrete beams are reinforced with either steel reinforcement or prestressed with steel strand. They may be designed to act compositely with the floor. They can also be designed to be monolithic with columns especially where these are in-situ elements. Where the beams are supporting precast concrete floor units the beam profiles are generally inverted T-beams or L-beams with the nib designed to support the floor unit. However, other profiles can be manufactured.

Columns

Precast columns are generally square, rectangular or circular, although other shapes are possible and can be cost-effective where there are a large number of repetitions. Increments of 50mm on the dimensions of faces of square and rectangular columns are preferred. The preferred increment for the diameter of circular columns is 50mm. Circular columns are routinely cast vertically, limiting them in most cases to single-storey height. Rectangular and square columns can be cast horizontally and the maximum height of columns without splices is generally between 20m and 24m although 15m to 16m is often more economic. Where the columns are continuous through one or more floor levels they can have corbels or structural inserts to provide support for beams.

Twinwall

Twinwall consists of two precast concrete panels held apart by a lattice girder manufactured from steel reinforcement. The precast concrete panels form both a permanent shutter for the in-situ concrete and contribute to the final structural element. The surface finish of the panels are good quality and usually only require a skim coat of plaster. The advantage of using an in-situ concrete infill is that the elements can be readily tied together to form a robust structure. Twinwall panels can be used for: · Basement walls. · In combination with lattice girder slabs to form cellular structures. · Core walls or lift shafts. · Residential structures with load-bearing party walls.

Using precast concrete elements can: · Speed-up construction · Provide high-quality finishes · Reduce costs

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Stairs

Precast concrete stairs offer a quick method of providing safe access routes during construction. They remove the need for complicated on-site shuttering and provide a high quality finish. They generally do not require temporary propping and are often connected to floors and landings using steel angle joints. Other connections such as continuous halving joints and intermittent halving joints are also used. Combined stairs and landing units are also available. Precast concrete stairs are particularly cost-effective when duplicated or based on manufacturers' standard mould sizes. The greater the number of identical units required, the lower the cost.

Balconies

Precast concrete balconies are manufactured mainly for use in apartment complexes. Units have steel reinforcing bars projecting from the back which tiein with the steel reinforcement in the concrete floor structure. Balcony units are temporarily supported until the structural floor or screed has been placed and reached sufficient strength. Precast concrete balcony units typically have integral drainage slots to receive drainage outlets and an upstand to facilitate proper weatherproofing details at door thresholds. They may also incorporate tiled upper faces and cast-in fittings for balustrades. There are proprietary systems available to minimise cold bridging which can be incorporated into the precast balconies.

St George's Wharf, London.

Courtesy of Marble Mosaic.

Bathroom Pods

The structure for a bathroom pod can be manufactured in precast concrete. The structure generally consists of thin concrete walls and floor with a single layer of reinforcing mesh. Services such as electrical conduits and pipework can be incorporated into the concrete structure. After casting the concrete pod the bathroom is fully fitted out, including all the finishes. The finished pod is delivered to site and lifted into position ready for final connection of the services.

Terracing

Precast concrete is used extensively for terracing in grandstands, stadia and auditoria. Precast concrete provides a strong, durable and versatile terracing unit that is quick and easy to install. Importantly, it can easily be designed to meet the vibration criteria for sports grounds. There is a large range of associated products including stairs, vomitories, steps, raking beams and columns that will enable the structure, as well as terracing, to be constructed in precast concrete if required.

Precast concrete stairs provide quick, safe access. Courtesy of Tarmac.

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ARCHITECTURAL CLADDING PANELS

Factory produced precast concrete cladding offers almost unlimited scope for architectural expression. A wide variety of low maintenance and extremely durable surfaces are available, including self-finished options and a range of applied materials. The panels can be either supported by the frame, be self-supporting, restrained by the frame or be designed to support the floors.

The use of precast concrete cladding panels offers many advantages: · Panels are produced by skilled craftsmen in purpose-built factories and each stage of manufacture is inspected in accordance with an independently certified quality system. · Finish and dimensional accuracy are verified prior to delivery. · Panels are produced off-site while the foundation and frame construction proceed, enabling them to be delivered and installed on a just-in-time basis. · Panels are erected by teams of specialists who have been trained in their safe handling and fixing. · External scaffolding is generally not required as fixings are accessed from the rear of the panels. · Panels can be delivered with windows and insulation fitted in the factory thus further accelerating the work of following trades. · Negligible waste is produced during production of units as they are fully engineered in the factory. Sustainability is further enhanced by the ability to dismantle the cladding at the end of the economic life of the building with panels potentially being refurbished for further use or crushed to provide recycled aggregate and scrap steel. · Variety can be introduced with clever use of the moulds. Self­finished precast concrete cladding panels are typically 150mm thick and their size is limited only by site cranage and/or transportation constraints. These are frequently overcome by use of low-loader trailers which allow storey-height panels to be delivered ready for off-loading and hoisting directly into place on the structure.

Self-supporting Panels (stacked façades)

Cladding panels are often 150mm thick and therefore have considerable strength to carry vertical loads. An efficient system is therefore to design the panels to be self-supporting by stacking them on top of each other (see diagram (b) below) and using the frame to tie them in the lateral direction. The advantage is that the frame carries significantly less load and can be lighter. Differential movement between the frame and façade must be accommodated by the restraint system. They are sometimes referred to as `structural panels'.

Applied-finish Panels

Typical factory applied finishes include terracotta, glazed bricks, brick-slips and tiles and stone facings such as granite, limestone and slate (used in thicknesses from 30mm to 50mm depending upon the stone). An individual panel may incorporate in excess of 100 pieces of stone or more than 1000 bricks. Panels may also include a mix of applied and self-finishes that on-site would demand separate trades or skills with attendant sequencing and management.

Load-bearing Structural Panels

Alternatively on-site the panels can be designed so that they act as part of the structural frame (see diagram (c) below). The cladding panels (usually sandwich panels) at the perimeter of the building support the floors, slabs and beams. The advantage is that there is no requirement for perimeter columns which increases the floor area and gives a flush wall profile. It does however require close co-ordination by the project team and the cladding system becomes part of the critical path for the frame construction.

Individually Supported Panels

The panels are designed to span either from column to column or floor to floor (see diagram (a) below), allowing large areas of the structure to be rapidly enclosed and subsequent weather-dependant trades to proceed. The panels are fixed to the frame with brackets that are designed to allow for adjustment in three directions. Usually there is a bracket at each corner of the panel.

Self-finished Panels

The most cost-effective cladding panels are those with self-finishes, often using carefully selected materials to create an appearance intended to mimic a particular natural stone. The surfaces produced may be textured or highly polished and the surface treatments adopted to achieve them include: · Bush hammering · Abrasive blasting · Acid etching · Mechanical grinding and polishing · Surface retarding · Rubbing Panel support options a) Individual panel supported by frame

Cladding panel Cast-in socket Shims for vertical tolerance SS angle supporting panel fixed to frame Bearing shims for tolerance

Insulation

The insulation required to meet the requirements of Part L of the Building Regulations can be pre-fixed to the concrete panel in many ways: · Fixed to the back of the panel, ready for internal finishes to be added on site. · Fixed between concrete and the applied finishes in the factory. · Fixed between two layers of concrete (sandwich panel) in the factory.

b) Panel supported by panel below

Cladding panel Cast-in socket Shims for vertical tolerance Cast-in socket Horizontal restraint bracket Cast-in socket

c) Load bearing panel

Cladding panel Horizontal restraint bracket

Structural frame Horizontal restraint bracket

Structural frame Horizontal restraint bracket

Shims for vertical tolerance Cladding panel

Structural floor Interface between floor and supporting panel varies depending on floor system

Precast Concrete in Buildings

PAGE 11

EXAMPLES OF ARCHITECTURAL FINISHES

Bush hammered Aggregate transfer Acid etch

Light grit blast

Medium grit blast

Heavy grit blast

Reconstituted stone finish at St George's Battersea Reach, London.

Courtesy of Marble Mosaic.

Brick pre-fixed to precast concrete at 77 Grosvenor Street, London.

Courtesy of Trent Concrete.

Polished concrete at Beetham Tower, Manchester.

Courtesy of Trent Concrete.

Slate pre-fixed to precast concrete at Swansea Museum.

Courtesy of Trent Concrete.

Precast concrete with cast in flints at West Quay car park, Southampton.

Precast concrete panel showing exposed aggregate.

Precast Concrete in Buildings

PAGE 12

Billet connection

Shims for vertical adjustment Precast column Precast beam Bolt (often recessed) Hollow steel, or solid plate (Billet) cast into column

JOINTS AND CONNECTIONS

There are a number of different methods for connecting precast concrete elements. Joints transmit forces between the structural elements, giving the necessary strength and Precast Precast column Precast Precast robustness to the structure. The joint must also be capable of withstanding abnormal loads beam beam column caused by fire, impact, explosion or subsidence. In order to provide a robust structure, Steel the designer should ensure that the failure of a single joint does not lead to structural section Bearing material `T' cleat with gusset, cast into instability.

column bolted to column and beam Fixing cleat

Bolted cleat with a socketed beam-end a) Billet connection

Beam to Column

b) Bolted cleat with a socketted beam-end The most typical beam to column connections Fixing cleat include the following:

Precast beam

c) Corbel with recessed beam-end There are three main methods of fixing precast concrete columns to an in-situ foundation:

Column to Foundation

Bolted or baseplate connections

Steel baseplates are attached to the precast concrete column during manufacture. The column is then fixed to the in-situ foundation using cast-in holding Precast down bolts to form the connection. Alternatively, the Insitu concrete column bolts through the precast column baseplate can be or grout post-fixed onto an existing Shims for base.

vertical adjustment

t

Precast column Precast Steel column section cast into column Grout tube

Steel billets with a socketed beam-end Precast Precast beam The has a steel billet or rectangular hollow column columnPrecast

section projecting from its face(s), which supports column the beam end via a bearing plate on the soffit of the Large diameter Bearing material Grout tube socket.

sleeve Projecting

d)

Dry pack `T' cleat with gusset, bolted to column and beam Precast beam Shims for vertical adjustment Dry pack Corbel with recessed beam-end sleeve Grout

b) Bolted cleat with a socketted beam-end

Projecting Precast reinforcing column bars in lower column Precast beam

Shims for vertical tolerance Precast Fixing cleat Precast column beam Precast Bolt (often recessed) beam

A steel section is cast into the column, to which is from foundation tolerance bolted a gusseted tee-cleat, which in turn supports c) Corbel with recessed beam-end the socketed beam-end.

Precast Insitu

Shims for Bolted cleat with a socketed beam-end reinforcing bar vertical

column Corbels with recessed beam-endPrecast foundation beam

et, nd beam

Precast column Precast d) Continuous beam connection column Hollow steel, or solid plate Large diameter (Billet) cast intotube Grout column Bearing material sleeve Shims for vertical Column tolerance reinforcement welded to c) Corbel beam connection Continuous with recessed beam-end baseplate Base plate Insitu Non-shrink foundation grout Precast Precast Precast column column column Insitu Holding down bolt Grout tube Dry pack Projecting reinforcingconnection a) Billet bar Precast column from foundation

Corbels are most often used where heavy loads or Steel long span beams have to be supported.

Precast The column Precast Insitu starter-bars are cast into the in-situ base. The beam concrete column can then be lowered onto the base, precast Precast Shims for vertical tolerance foundation starter-bars projecting into dowel tubes Precast with the beam column in the precast columns. The (often recessed) Bolt dowel tubes are provided

Projecting

Fixing cleat starter-bars

then grouted up.

section Bearing material solid plate Hollow steel, or `T' cleat with gusset, f) Pocket connection to column foundation e) cast into starter-bars for column Projecting (Billet) cast bolted to column and Connections between beams and beam In-situ pocket foundationinto column column foundation conections

single-storey height columns Precast

m-end

nt

need to be continuous over the support, for example b) a cantilever. with socketted beam-end to create Bolted cleatBeamsaare seated on a dry-pack mortar joint and projecting reinforcement from the lower column is passed into the upper Insitu column through sleeves in the beam, which are concrete subsequently grouted. for vertical tolerance Shims foundation

Insitu concrete This type of connection may be used where beams column or grout

The in-situ pocket foundation will provide a fixed base connection to the precast column, which is a) Billet connection particularly useful where the cantilever action of the column provides the lateral stability c) Corbel with recessed beam-end for the building. The column is embedded into the pocket pad foundation by a distance of at least 1.5 times the minimum column cross section or base dimension. Grout tube The pocket is then filled with grout or in-situ Precast concrete. column Dry pack

Precast column Dry pack Projecting reinforcing Insitu bars in concrete lower column foundation Precast Insitu concrete beam or grout Grout sleeve Shims for vertical tolerance Precast column Shims for vertical tolerance

Fire

recast t eam

ecessed) ed) ube

r eplate mn e

Shims for vertical tolerance foundation Steel Steel Precast beam section section column concrete `T' Insitu with gusset, cast into `T' cleat cleat gusset, with cast into or to boltedgrout Dry pack column bolted columncolumn and Grout sleeve g)column Baseplate connection to to column and beambeam foundation

Exposed bolts and steelwork used in these Precast Precast Precast Large Precast diameter Grout tube Precast Precast connections connection to column foundation e) Projecting starter-bars for column beambeam f) Pocketsleeve may require fire protection. beam beam column column concrete foundation conections Precast Projecting

Shims for reinforcing bar vertical from foundation Bearing material Bearing material tolerance

Fixing Fixing cleat cleat Precast Protection column

Shims for Projecting vertical tolerance reinforcing Insitu Precast column bars in lower foundation Insitub) Bolted cleat with a socketted beam-end c) Corbel with recessed beam-end column c) Corbel with recessed beam-end b) Bolted cleat with a socketted beam-end concrete Shims for vertical tolerance foundation

d) Continuous beam connection f) Pocket connection toto column foundation Baseplate connection column foundation

d) Continuous beam connection Projecting starter-bars for column foundation connections f) Pocket connection to column foundation Precast

Precast column column Precast column Large diameter Large diameter sleeve sleeve Column Grout Grout tube tube reinforcement welded to Shims Shims for for baseplate vertical vertical tolerance Holding tolerance down bolt

e) connection to column foundation Pocket Projecting starter-bars for column foundation conections

n

Precast column Precast Precast column column InsituInsitu concrete concrete or or groutgrout

on cast m

Projecting Projecting reinforcing Base bar reinforcing plate bar from from foundation foundation Non-shrink grout

Base plate Non-shrink grout

Column reinforcement welded to baseplate Holding down bolt

nce n

InsituInsitu Insitu foundation foundation concrete Shims for vertical tolerance foundation

InsituInsitu concrete concrete foundation foundation

Shims for vertical tolerance Shims for vertical tolerance

Insitu concrete foundation

Shims for vertical tolerance

f) Pocket connection to column foundation e) Projecting starter-bars for column f) Pocket connection to column foundation e) Projecting starter-bars for column g) Baseplate connection to column foundation foundation conections foundation conections

g) Baseplate connection to column foundation

Precast Concrete in Buildings

PAGE 13

PRODUCTION

This section explains the systems and techniques used by the precast industry and will increase understanding of the processes.

Production Techniques

Floors

Hollowcore, solid prestressed units, lattice girder units and beams for beam and block floors are manufactured on either long-line steel casting beds or in purpose made steel moulds, often using automated casting techniques. The steel beds used for prestressed elements are thoroughly cleaned prior to use and a release agent is applied to produce a quality surface finish. Reinforcing strands are placed on the bed and hydraulically tensioned. The concrete is then placed using either extrusion, slipform or wetcast machines. All necessary slots and openings are marked and cut. Once the concrete has obtained sufficient strength the strands are released, thus prestressing the concrete. The strands at the end of each unit are then cut. Where long line beds are used saw-cutting is used to produce individual units to the required lengths.

Curing

The curing process is an important part of component manufacture. Heating the concrete accelerates curing. Heat is applied in various ways such as steam or hot water running through a network of piping. Other methods include the use of hot air and the application of electrical current through reinforcing strands which act as heating elements. Covering the components with insulating sheets to retain heat and moisture helps the curing process.

Component Drawings

Drawings are produced by the precast concrete manufacturer for every element showing all relevant information, such as reinforcement, the position of fixings, penetrations, cast-in items, openings and lifting anchors.

Moulds

The main mould types include:

Quality

Considerable emphasis is placed on quality control at all stages in the production of precast concrete components. Precast concrete manufacturers generally manufacture in accordance with ISO 9001 standards or with other internal quality systems. Key areas of quality control include: · Test certificates for materials · Compressive strength testing · Consistence (workability) testing · Mould standard and quality checks · Correct preparation of reinforcement cages/ strands check · Cast-in components and fittings checks · Dimensional checks ­ both before and after casting · Assessment of early age strength · Quality of finish inspection

Adjustable long-line mould systems

These can be used to cast a variety of beam and column sections. The flexibility to cast sections, in a range of sizes, from one mould, ensures optimum productivity and facilitates the quick turnaround of precast components required on fast-track construction programmes.

Flat table moulds

These are generally used to form panel members. Formers are quickly fixed to the steel faced mould with magnetic clamps. After casting formers are removed and the panel is lifted off the mould.

Wall panels

Panels are produced in flat beds, vertical battery moulds, horizontal tilting tables or carousel systems (carousel systems allow units to be moved around the factory for each stage of manufacture). Wall panels produced in vertical battery moulds have a smooth surface on both sides. Panels produced on flat beds and tilting tables have one moulded face and one side with a trowelled finish. A trowelled finish is used where walls have further finishes to be applied or where the face of the panel is concealed inside a cavity wall. Lifting points are cast-in which are used in the de-moulding process and when erecting the finished units on-site.

Tilting table moulds

Their use reduces the handling stresses on panels and can therefore reduce the amount of handling reinforcement which has to be cast into the unit.

Battery moulds

These consist of a series of steel faced sections with variable perimeter formers positioned to create the required dimensions. These sections open apart to allow preparatory work and are then mechanically closed and clamped together to form a multi-cast mould. Typical applications would include retaining wall panels and other panel sections complete with door and window openings, suitable for apartment or housing developments.

Handling and Storage

When the units have reached the required strength, they are removed from the mould and labelled for later identification. They are then stacked on bearers placed at suitable locations or in the case of wall panels, sometimes in rack systems.

Stairs

A number of systems are available for casting stairs which can be cast in bespoke moulds or in adjustable moulds. Units can be cast in the upright position or in the inverted position. Alternatively, units can be vertically cast on their edge giving a mould finish to the top and underside of the stairs and leaving one side to be hand finished. Simple stair units, or a combined stair and landing unit, can be produced in a variety of finishes.

Specialised or bespoke moulds

These are manufactured to produce a specific one-off range of products. Moulds can be manufactured from different materials such as timber, steel or fibreglass and may be lined with a range of purpose-made patterned liners to imitate natural finishes. The choice of mould material is usually determined by the number of casts required and the complexity of the shape and size of the finished product. Specialised moulds can be made to be adjustable and hence may be used for similar projects in the future.

The precast industry is constantly developing, as shown at Bison Concrete's state-of-the-art precast factory at Swadlincote, Derbyshire. Courtesy of Bison Concrete.

Precast Concrete in Buildings

PAGE 14

University of East London. Five seven-storey and four three-storey structures, creating 788 bedrooms, were erected within 33 weeks using crosswall construction.

Courtesy of Bell and Webster.

SITE ERECTION

The speed of construction is rapid and must be planned in advanced to ensure an efficient and safe process. This section explains the erection process and pre-planning that is undertaken.

Floors

Before installing floors, passive fall protection (by means of, for example, crash-deck, air bag or netting installation) should be in place.

Stairs

As with floor installation, adequate provision to prevent falls should be in place before installation of precast stairs commences. Consideration should also be given to installation of temporary handrailing to the stair units to avoid undue risk to the operatives carrying out the work.

Method Statement

At the commencement of each project, a method statement confirming how the elements will be manufactured, transported and erected should be prepared. The headings covered in this statement should include: · Safety (including the mandatory safety statement) · Handling/cranage and transportation (with due consideration to the weight of the units) · Site erection (procedure, programme, sequence) The design for temporary conditions during erection should take into account overall stability and the stresses in individual elements and joints. Load paths through a partially completed structure may be different for those in a completed frame. An example is the temporary state when floor units have been placed on one side only of an internal beam. Here the connection should be checked for its resistance to torsion and if necessary, propped until the slabs on the other side of the beam are placed in position. The design and positioning of any temporary propping and of the bases are critical to the successful erection of a precast structure. Fixing points for props may be incorporated in the design and provided in the precast elements.

Hollowcore

Units are craned individually into approximate position and then finally positioned by one of the following methods: · lifting with beam clamps · lifting via integral lifting points · barring (final positioning using a crowbar) Bearings must be sufficiently robust to withstand these operations. When placing units on masonry, the mortar must be allowed to achieve adequate maturity before installation commences. The outer leaf of cavity walls must be built up to within 225mm of the inner leaf and fully tied. The units are then grouted using a small aggregate concrete to provide initial stability and the joints sealed before any subsequent floor finishes are applied.

Access and Cranage

The following are some of the issues which will be taken into consideration by the precast supplier before choosing a crane and finalising the construction sequence: · Public safety and on-site safety · Component sizes and weights · Maximum reach of the crane from set-up position to final component installation · Any constraints such as overhead power lines · Availability of secure standing areas for cranage · Ground bearing pressures for crane loads

Beam and block

Units are either delivered in bundles and their position adjusted manually or positioned approximately with finger grabs. The infill blocks/tray blocks should then be installed manually and the floor grouted before placing screeds or other floor finishes.

Lattice girder/solid prestressed floors

Units should be craned into position and grouted before topping concrete is placed.

Precast Concrete in Buildings

PAGE 15

MAXIMISING THE BENEFITS OF PRECAST CONCRETE

Early Involvement of Precast Supplier

The UK precast concrete industry has years of experience working on a vast range of projects. To obtain the maximum benefit of this experience, it is advisable to involve the precast concrete manufacturer at the earliest opportunity. The precast industry is pleased to give initial advice and contact details can be obtained from the trade associations (see below). If a hybrid concrete structure is being considered then reference should be made to Best Practice Guidance for Hybrid Concrete Construction[16], for guidance on procurement.

Lead-in Times

The design team should be aware of the lead-in times for the type of precast concrete they are intending to use. Some elements can be obtained in a short period because they are relatively standard (such as hollowcore units) whereas other elements are more bespoke and a longer period should be allowed for co-ordination, design, mould production, casting and delivery. Precast suppliers can advise appropriate lead-in times for individual projects.

The UK precast industry has a wealth of knowledge and can advise on: · Maximising standardisation · Lead-in times · Detailing · Surface treatments · Erection

Co-ordination

Before the final design of precast concrete can be carried out, the design requirements should be fully co-ordinated with the design team. A key area to resolve is the location and size of service voids. Once on-site, precast elements are installed quickly. It is therefore important to programme the work to maximise the speed of construction and avoid stopstart erection.

Component Standardisation

Well-designed frame elements in standard sizes can facilitate economic construction. The dimensions of beam and column sections should be standardised wherever possible, allowing the precast designer to fully utilise available moulds. The structural grids may have offsets which form curved or other irregular shapes, without compromising the general uniformity of the structural grid. This technique is used to good effect in many buildings where a curve is required in one section of the building or in some of the elevations. The precast industry can give advice to help achieve standard components.

Wembley Park Station Capacity Enhancement, London, uses reconstituted stone to frame its curved facades.

Courtesy of Decomo.

Precast Concrete Trade Associations

British Precast (www.britishprecast.org) is the umbrella body for the UK precast concrete industry. It has three product associations specialising in precast systems for buildings. For information on other precast products visit: Structural Precast Association www.structural-precast-assocation.org.uk Architectural Cladding Association www.architectural-cladding-assocation.org.uk Precast Flooring Federation www.pff.org.uk

Precast Concrete in Buildings

PAGE 16

CASE STUDIES

Twickenham South Stand, Twickenham

A new South stand was required at Twickenham to match the profile of the existing East, North and West stands constructed up to 15 years earlier.

Chessington College, Kingston

A precast concrete structural frame was chosen for the teaching block at Chessington Community College, a `one-school pathfinder' project for the Royal Borough of Kingston-upon-Thames. The three-storey college facility was constructed by Composite Structures Ltd in two phases.

Waste Treatment Centre, Frog Island, East London

This is a new waste treatment facility for recycling and disposal of household rubbish for the boroughs of Havering, Barking and Dagenham. A precast concrete building has been built to house the state of the art treatment facilities.

Why precast was chosen

Precast concrete was chosen to match the existing in-situ concrete while, at the same time, providing a fast erection programme. The lower tier of the structure was erected in just eight weeks and was critical to enabling this part of the stand to be used for an important international rugby match. The 2,200 units were erected in that period, including columns, beams, terracing, vomitory walls and shear walls. Precast terracing units and raking beams at Twickenham South Stand.

Why precast was chosen

Where feasible, the project architect - Initiatives In Design (IID), made a feature of the precast concrete frame by leaving it exposed. This allowed IID to meet Kingston RB's key requirements for an innovative learning environment, including space flexibility, energy efficiency and an ability to adapt to advances in technology and education during the next 20 to 30 years. Composite Structures's precast concrete teaching block takes shape at Chessington College, Surrey.

Why precast was chosen

As the waste treatment equipment was supplied by Ecodeco, which has other precast operating plants across Europe, it was decided to use the same construction solutions at the East London site. Concrete also offers a huge level of durability in the harsh environment. Precast cladding provides weather protection to the building.

Courtesy of Tarmac.

Construction

Two-span precast raking beams, which weigh 10 tonnes, span from ground level at the perimeter of the pitch onto a central circular precast column and then onto an in-situ concrete Vierendeel sway frame. Precast concrete beams span between the rear two bays of precast flooring providing spectator concourses on two levels. The last 10 bays at each end of the South stand curve round to meet the East and West stands which support the end bay of terracing. Therefore the precast structure connects to concrete cast previously from ready-mix concrete on four edges. This required careful control of tolerances during detailing, manufacture and erection to achieve a good fit of the structure within its peripheral constraints. A further 1,800 precast units were used for the middle and upper tiers as well as 18,500m2 of prestressed hollowcore and solid slab flooring together with 220 stair flights.

Construction Construction

The precast concrete hollowcore units are 450mm deep for spans up to 15.5m and 260mm deep for spans up to 9.6m. They are supported on precast beams, which, in turn, are supported by precast concrete columns springing from the foundations. The whole structure is erected very quickly, giving a safe working platform for follow-on trades. The precast concrete finish is suitable for direct decoration. The facility comprises a Mechanical Biological Treatment facility (Bio-MRF) which processes 180,000 tonnes that was previously sent to landfill. The Bio-MRF process turns 50% into recoverable fuel and also separates metals and glass to be reused in industry. The roof of the building consists of 1800mm wide double tee units. These are 900mm deep and span 21.25m. These units are supported by precast perimeter beams, which in turn are supported on precast columns. Precast concrete cladding units were also used to provide weather protection to the building.

Project team

Architect: Initiatives In Design Project manager: Tuffin Ferraby Taylor Main contractor: Willmott Dixon Construction Precast concrete supplier: Composite Structures

Project team

Client: Shanks (East London Waste Authority) Main Contractor: Kier Construction Contractor: Ecodeco Precast concrete supplier: Tarmac Precast Concrete

Project team

Precast concrete contractor: ABC Structures Precast concrete supplier: Bison Concrete Products

Precast Concrete in Buildings

PAGE 17

REFERENCES

To download or access many of these publications, visit www.concretecentre.com/publications 1. Concrete and Fire, TCC/05/01, The Concrete Centre, 2004 2. Concrete and Sound Insulation, TCC/04/03, The Concrete Centre, 2006 3. Pavic A, Reynolds P, Prichard S and Lovell, M, Evaluation of mathematical models for predicting walking-induced vibrations of high-frequency floors, International Journal of Structural Stability and Dynamics Vol. 3, No. 1, 107-130, 2003 4. Wilford, MR and Young P, A Design Guide for Footfall Induced Vibration of Structures, CCIP-016, The Concrete Centre, 2006 5. Thermal Mass, TCC/05/05, The Concrete Centre, 2005 6. Thermal Mass for Housing, TCC/04/05, The Concrete Centre, 2006 7. De Saulles, T, Utilisation of Thermal Mass in Non-residential Buildings, CCIP-020, The Concrete Centre, 2006 8. Waste & Resource Action Programme, Waste Reduction Potential of Precast Concrete Manufactured Offsite, WAS003-003, WRAP, 2007 9. Sustainable Concrete, TCC/05/03, The Concrete Centre, 2007 10. Crosswall Construction, TCC/03/26, The Concrete Centre, 2007 11. Hybrid Concrete Construction, TCC/03/10, The Concrete Centre, 2005 12. Goodchild CH and Glass, J, Best Practice Guide for Hybrid Concrete Construction, TCC/03/09, The Concrete Centre, 2004 13. Taylor HT and Whittle R, Hybrid Concrete Construction Design Guide, CCIP-030, The Concrete Centre, due 2008

Listed below are other publications in this series. To download or order free hard copies of any of these publications visit www.concretecentre.com/publications.

Concrete Framed Buildings

Concrete Framed Buildings

At the start of each project, a decision is made about the form and material for the structural frame. This publication sets out to help the designer come to an informed decision, giving likely structural options for a concrete frame, with useful points to note written by engineers for engineers. The publication also discusses issues facing designers and provides background information on sustainability, innovations in concrete and best practice. Publish date: 2006 TCC ref: TCC/03/024

A GUIDE TO DESIGN AND CONSTRUCTION

Thermal Mass

Thermal Mass

A CONCRETE SOLUTION FOR THE CHANGING CLIMATE

Our climate is already changing and will continue to change significantly within the lifetime of buildings designed today. This publication provides a general guide to understanding thermal mass and fabric energy storage (FES). It outlines the application of FES techniques using cast in-situ and precast concrete floor slabs in non-domestic buildings and gives readers full references to facilitate further reading. Publish date: 2005 TCC ref: TCC/05/05

The entire concrete and cement industry in your office

The Concrete Centre provides continuing professional development at your fingertips. A wide range of presentations, all of which are CPD-certified with approved learning outcomes, are free of charge and can be delivered in your office by our expert team of regional engineers.

Hybrid Concrete Construction

Hybrid Concrete Construction (HCC) combines precast concrete and cast in-situ concrete to take best advantage of their different inherent qualities. This publication provides an overview as to how this can be done. Publish date: 2005 TCC ref: TCC/03/010

For more information visit www.concretecentre.com/cpd

If you have a general enquiry relating to the design, use and/or performance of cement and concrete in construction please contact our national helpline.

Crosswall Construction

Crosswall Construction

Crosswall is a modern and effective method of construction which uses precast, cellular concrete components to achieve structurally robust, fast, economical medium and high-rise buildings. This publication explains the benefits of using crosswall construction and includes case studies of projects which have benefited from its effectiveness. Publish date: 2007 TCC ref: TCC/03/26

HIGH PERFORMANCE BUILDINGS USING CONCRETE FRAMES AND CLADDING

Advice is free and available Monday to Friday from 8am to 6pm. Call 0845 812 0000 Email [email protected]

CI/SfB

UDC

Precast stairwells at Swansea Liberty Stadium.

Courtesy of Tarmac.

The Concrete Centre, Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB National Helpline Call 0845 812 0000 Email [email protected]

Ref. TCC/03/31 ISBN 1-904818-51-x First published 2007 © The Concrete Centre 2007

All advice or information from The Concrete Centre is intended for those who will evaluate the significance and limitations of its contents and take responsibility for its use and application. No liability (including that for negligence) for any loss resulting from such advice or information is accepted. Readers should note that all The Concrete Centre publications are subject to revision from time to time and should therefore ensure that they are in possession of the latest version.

www.concretecentre.com

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