Formwork

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Safety on site

Many construction activities are potentially dangerous so care is needed at all times. Current legislation requires all persons to consider the effects of their actions, or lack of action, on the health and safety of themselves and others. Advice on safety legislation can be obtained from any of the area offices of the Health & Safety Executive.

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Concrete

on site

Formwork The downloadable booklets in the Concrete on site series are a continuation of a series originally issued in 1951 and have become standard guides to site personnel.

CONTENTS Health awareness The sign of a job well done What’s needed for good formwork Design Materials How to erect formwork Using a release agent Checks before concreting Striking the formwork Further reading

Concrete on site 3 - Formwork OS003 © The Concrete Society 05/10



Formwork HEALTH Awareness Dry cement powders in normal use have no harmful effect on dry skin. As with any dusty material there may be ill effects from the inhalation or ingestion of cement dust and suitable precautions should be taken. When cement is mixed with water, alkali is released. Precautions should therefore be taken to prevent dry cement entering the eyes, mouth or nose, and to avoid skin contact with wet concrete and mortar. Repeated skin contact with wet cement over a period of time may cause irritant contact dermatitis. The abrasiveness of the concrete or mortar constituents can aggravate the effect. Some skins are sensitive to the small amount of chromate that may be present in cements and can develop allergic contact dermatitis, but this is rare. Continued contact with the skin can result in cement burns with ulceration.



Note that with alkali burns, pain is not immediate.

Whenever there is persistent or severe irritation or pain a doctor should be consulted.

Handling precautions

Protection for the eyes, mouth and nose should be worn in circumstances when dry cement may become airborne. When working with wet concrete or mortar, suitable protective clothing should be worn, such as longsleeved shirts, full-length trousers, waterproof gloves with cotton liners and wellington boots. Clothing contaminated with wet cement, mortar or concrete should be removed and washed before further use. Should concrete or mortar get into boots, remove them IMMEDIATELY and thoroughly wash the skin and the inside of the boots before proceeding with the job. If cement enters the eye it should be washed immediately and thoroughly with clean water and medical advice sought. Concrete or mortar elsewhere on the skin should also be washed off immediately.

THE SIGN OF A JOB WELL DONE There is an easy way to tell whether a concreting project has been carried out properly or not and that is to check its appearance when the job is finished. Good construction will look attractive, whereas work that has been carried out in a careless, slapdash manner will not. Formwork is one of the two most important factors that decide how the concrete will look in the final result (the other being the way the concrete is placed and compacted). This publication deals with the formwork; for advice on placing and compaction, refer to Concrete on site 5: Placing and compacting. Formwork is the mould for the wet concrete. It shapes it, and holds it in place until it has set and hardened. Any defects in the formwork will show on the as-struck concrete

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Formwork is made from many materials including:  Timber  Aluminium  Plywood  Steel  Plastics  Polystyrene  Expanded metal sheet  Cardboard.

Formwork surface, so it is essential that all the operations are carried out with great care. Formwork is made from expensive materials and needs great skill in its fabrication. Its importance can be judged from the fact that fabricating, erecting and striking it often cost more than the concrete it is designed to shape and support. Because of this, formwork usually needs to be re-used over and over again. This will be possible only if it is handled, cleaned and stored properly and responsibly. A high standard of workmanship is necessary to produce a high standard of concrete work. Much depends on the skill and expertise of the workforce, although good quality can be achieved in simple, highly repetitive work with less skilled labour. There are specialised proprietary formwork systems i.e. slip forms, jump forms, and tunnel forms. These are not covered in this booklet.

The concrete in the finished job will provide a lasting commentary on the skills of all those involved in the construction.

4. It should be possible to strike the formwork easily and safely and without causing any damage to the concrete.

WHAT’S NEEDED FOR GOOD FORMWORK

Design

As far as the operative on site is concerned, there are four requirements for good formwork: 1. It should be built to ensure that the concrete is formed to the required shape, size and position, as well as providing the required surface finish on the concrete. 2. The supporting system for the formwork - the tie rods and alignment members of wall forms, or the supports, lacing and bracing of formwork for slabs - must be installed in accordance with the formwork drawing and the supplier’s recommendations. 3. Formwork should be securely fixed and all fixings needed for erecting subsequent formwork should be included.

Fig 1. Formwork construction

There are four main areas for formwork; walls, columns, beams and slabs. Formwork for the underside of suspended slabs and beams is known as soffit formwork. The supporting structure of formwork is known as falsework. Wall formwork will be either doublefaced (in which tie rods keep the two faces from spreading apart under the pressure of the concrete) or single-faced e.g. that for the edges to small bases and pile caps. Supporting single-faced formwork calls for careful consideration and for heights of 1m or more the formwork should be specially designed for the purpose. Soffit formwork needs to be supported typically by steel or alumin

Formwork ium vertical members. On smaller contracts, adjustable metal props are often used as falsework, but proprietary deck support systems are common for larger slabs. The latter have replaced the traditional tube-and-fitting supports, which were labour intensive. There are often many possible solutions to the formwork problems that could crop up on site. These might involve the use of traditional methods, or proprietary equipmentsometimes a combination of both. Wall formwork, for instance, is very often made from plywood panels supported by timber walings and proprietary steel soldiers. No matter what arrangement is used, a drawing will be required. This need not necessarily be a design drawing; a simple sketch will do for small jobs. But it is vital that all aspects of the problem have been fully considered. This is especially true for a large clear-span soffit arrangement, or a cantilever section of slab.



It is important to follow the arrangement drawing as closely as possible, because it will have been devised by the formwork and falsework designer to suit the job in hand, to ensure that:  It is strong enough to take the pressure or weight of the fresh concrete during placing and compaction, as well as any other loads it might have to face. Weak forms will result in distortion, excessive deflections, leaks or other failure. These could mean that expensive repairs to the hardened concrete would be necessary.  It is easily and quickly erected and struck, thus saving time and money.  It is sufficiently stable in all weathers.  It is easily and safely handled using available equipment- including manhandling.  It provides suitable access for handling, placing and compacting the concrete.  It follows all the appropriate safety regulations relating to access, working areas, platforms, toe boards and guardrails.

 It has joints between members tight enough to prevent grout leakage, honeycombing and similar faults, which lead to a lack of durability and can spoil the appearance of the concrete in the finished job.

Materials

Fig 2. Traditional timber formwork, walings (left) and bearers

A wide range of materials is used for all parts of the formwork, from backing members to the various surface materials in contact with the concrete.

Timber

Timber is the most common of the various materials used for backing members to the form face, because it has the advantage of being easily cut and assembled on site. It is used as walings in wall forms and as bearers in soffit forms. Formwork made from timber is known as ‘traditional formwork’. This is because the construction methods that are involved have been used on sites for many years, and

Fig 3. Aluminium formwork is strong and lightweight

Formwork they are well understood by trained operators. Timber is graded by strength into classes. It is important to use the correct class of timber.

Aluminium

Take care not to damage the faces and edges of the plywood, especially when striking and during storage

However, a steel form can be reused on many more occasions than that - well over a hundred - provided it is looked after and stored properly.

Seal cut edges and tie rod holes with proprietary sealer or paint.

Plastics

A range of proprietary beams and smaller joists made from aluminium may be used in formwork.

Steel

Aluminium is strong and light, and often you need fewer supports and ties.

Proprietary systems usually consist of panels with steel frames, clad with either a plywood or steel facing. A range of adjustable props, soldiers, light walings and a variety of ties and accessories is available for securing the formwork in place.

The lighter sections will deflect more than equivalent steel or timber members, so always follow the formwork design and the supplier’s recommendations.

Plywood

Both traditional and proprietary formwork use plywood for panels. Ideally, the plywood should be framed up in the largest-size panel that can be handled on site. Plywood often has a strong and a weak way round, so make sure you always follow the supplier’s recommendations on this point.

Steel is used in both proprietary and purpose-made forms.

Purpose-made forms with steel faces are often used when dimensional tolerances are critical, or when it is planned that the form will be used over and over again. Such re-use obviously results in great cost saving, and it can be economical to specify steel when it is intended that the form will be re-used as little as, say, a dozen times.

Glass-reinforced plastics (grp) and vacuum-formed plastics are used when complicated concrete shapes or surface features are to be cast many times.

Fig 4. Steel frames may be inlaid with plywood or steel panels

However, you need to consider very carefully the type of release agent to be used on plastics. Vacuum-formed plastic will always need support, but grp can be fabricated with integral bearers that make it unnecessary to provide extra support for the face material. Plastic formwork can be reused many times, but you have to take care when placing and vibrating the concrete that you do not scour and damage the face.

Fig 5. Polypropylene and grp are often used to form the voids in trough and waffle floors

Proprietary waffle or trough formers, used on voided slabs, can be polypropylene.



Formwork Expanded Polystyrene

Expanded polystyrene can be sculptured to give a single-use sheet form liner. Its main advantage is the wide variety of shapes to which it can be formed. It is light and inexpensive, but requires a support system to withstand the concrete pressure. When used on voided trough and waffle slabs, it is coated with a plastic sheet material to allow it to be stripped cleanly. Although expanded polystyrene is used for forming openings and boxouts, it can be used only once, and is, therefore, wasteful. Also it can leave a skin of plastic on the concrete surface. However, if you face it with a rigid plastic sheeting, it can be less expensive than framed-up formers for openings and box-outs.

Expanded metal

Expanded metal can be used to form inexpensive faces where the finish is not important. It is often used to form stop ends. However, it is a material that cannot



be re-used, and does not necessarily have to be removed.

Bolt-hole boxes

Expanded metal’s main advantage comes when it is used in tall structures, for here it reduces formwork pressures.

Bolt-hole boxes can be made from many materials; timber, plywood, expanded metal, expanded polystyrene or foamed polyurethane or be obtained as ready-made proprietary inserts.

Cardboard

Proprietary Formwork

Cardboard that has been coated with a waterproof treatment is sometimes used as formwork for circular columns and for voids in bridges and slabs. Cardboard formers are generally used only once. They need to be well supported and braced to prevent them from being distorted and displaced by the concrete as it is being placed and compacted.

Other

Formwork may be permanent, remaining as part of the finished structure for example steel concrete composite decking. Form-face materials may also have permeable properties (controlled permeability formwork) which improve the surface characteristics.

Fig 6. Expanded metal formwork

A wide range of formwork panels, soldiers, falsework and fast-track systems is now available from various suppliers. Instruction manuals should be supplied along with the equipment. If you do not fully understand the procedures, do not hesitate to ask the supplier for advice. It is most important to establish that you are using the correct pieces of equipment. Mixing items from different suppliers can seriously affect the structural strength of the completed assembly, and must be avoided.

Fig 7. Proprietary formwork can save time

Formwork HOW TO ERECT FORMWORK All construction projects are different from one another, and have their own particular problems. However, this section covers the main points you should watch in order to avoid serious trouble when assembling and erecting formwork.  Use all panels in their correct positions. Paint numbers on them so that you can see at a glance which is which, and which way up they go.  Make sure that props, shores, walings, bearers, clamps and tie rods are the right size and at the correct spacing.  Check that the falsework is securely braced, and is on a firm foundation.  The correct washer plates should be used with all ties, and set square on frame members. This is especially important with sloping formwork. Do not overtighten ties, for this might cause distortion, and could result in failure of the tie when it is fully loaded.

 Forms fastened to previously cast concrete must be tightly fixed to prevent grout loss. Cellular foam plastic strips can be used to make a seal. Or, for very high-quality visual concrete, you can first gun a one-part, moisture curing, synthetic rubber sealant on to the old concrete.  Arrange the sequence of operations so that the formwork, and any opening formers or box-outs, provide a template from which the reinforcing steel can be properly spaced. This will ensure that the correct concrete cover is maintained in the finished work.  Any infill or closure panels, such as those needed to make up nonstandard lengths, should marry with the main formwork. Use a fixing method that allows you to fix and strip the infills without causing damage. Avoid cutting, or drilling holes in standard panels.  Holes that you have to make in the formwork should be neat, so that they can be patched or plugged later on. Drill timber from the face to avoid splintering.

 For high-quality work, the cut edge of the hole should be sealed in order to reduce water penetration.  Lightly tack all battens and blocking-out pieces so that they stay in the concrete during the striking of the formwork. Oil all boxes and block-out formers before placing any concrete, to ensure that they can be easily removed after the main forms have been struck.

Fig 8. Check formwork is erected correctly

 Satisfy yourself before concreting that all inserts and boxes are securely fixed, and check that they are slightly chamfered to make them easy to remove.  Be certain you understand which items are to be placed during concreting, and how they are to be fixed.  Pay particular attention to the rigidity and line of stop ends and joint formers, since these will be seen on the face of the finished work.

Fig 9. Drill timber from the face

 Remove all tie-wire clippings and nails, which will stain both the formwork and the concrete, and get rid, too, of any dirt and shavings. 

Formwork  Make sure that adequate access and working platforms are in place for concreting gang, and that toe boards and guard rails (including end rails) are provided.  Sloping or horizontal top forms are subject to upward pressures, and steps should be taken to stop them from lifting.  The weight of large prefabricated sections of formwork should be marked on them so that you can easily see what it is. Check that the capacity of the crane at the working radius is equal to lifting them. Lifting points are usually provided on the sections.  If necessary, a spreader or lifting beam should be used to prevent distortion. Make sure that inclined slings are long enough. The flatter they become, the less they can lift. If you plan to lift by the vertical soldiers, check that they are adequately connected to the walings.  When using proprietary systems, make sure you understand the manufacturer’s instructions. Any special tools needed should be obtained before work starts. 

Stop ends and day joints

Holes are often needed in stop ends to ensure that projecting starter bars for subsequent work are correctly positioned. Stop end forms are easily made from expanded metal, but if you use other materials special care is needed to ensure that the forms are grout-tight, and can be withdrawn from the hardened concrete- see Concrete on site No 7: Construction joints.

Propping to soffit formwork

To support the soffit and prevent excess deflect while it is gaining strength, propping must be carried out correctly. The props must be in good condition and erected properly, otherwise you risk having a dangerous collapse. The largest number of recorded accidents involving formwork have occurred because props, lacing, bracing and ties were left out of the falsework or taken away, often to provide access, then not put back. So, if it is necessary, make sure that only the minimum number of items is removed, that the details

are recorded and the parts always replaced. The load-carrying capacity of adjustable steel props is considerably reduced if they are erected out of plumb, and is further lessened if the load is applied off-centre. Bearers that are supported by props should be no more than 25mm off the centre of the prop head, and no prop should be more than 1 in 40 out of plumb i.e. 25mm in 1m.

Fig 10. Working platforms must be safe

Check the props by using a 1m spirit level to ensure that the end props in each row are vertical, and eyeing through the remainder. Check in both directions. A prop should not be used if it has any of these defects:  a bend or crease in the tube  corrosion other than slight rusting on the surface  a bent head or base plate  an incorrect or damaged pin.

Fig 11. Use the correct banksman’s signals for the crane driver

Formwork Above all, make sure that the props have a firm bearing and that they have sole plates. There are several good guides to the safe use of props. If in doubt, always seek advice.

USING A RELEASE AGENT The form-face in contact with the concrete needs to be treated with a release agent so that it can eventually be removed without adhering to, and damaging, the surface finish of the concrete. Release agents are prepared by the manufacturer to suit various requirements, and you must always follow the instructions. Never dilute a release agent, or mix different ones together. The agent is applied, before concreting starts and before the reinforcement is fixed, each time that the form is used. The various materials, such as timber, steel and grp, might each require a different type of release agent. Not all boards will

need a release agent so check the manufactures product data sheets. New timber and plywood are absorbent, so it may be necessary to apply a first coat of the appropriate agent in advance, then a second coat before they are used. Alternatively, any absorbent surfaces may be sealed with a suitable varnish, barrier paint or wax. A single application of release agent is all that is necessary when the forms are then used. Care should be taken to apply the correct amount of release agent. The most common fault is to apply too much. This can cause staining or retardation of the concrete surface. The right amount is a thin film applied uniformly by brush, roller or, preferably, spray. There is a simple check; touch the surface of the formwork when you have finished applying the agent; it should seem only slightly greasy. If you can feel or see that there is excess, wipe it off with a clean rag.

Remember that the agents are chemicals, and misuse can affect your health. If it is not possible to read the instructions on the container because they have become obliterated on site, see the COSHH regulations to find out whether any special precautions need to be taken. Never use oil from a container that is not clearly labeled, unless you are sure it is a release agent.

CHECKS BEFORE CONCRETING

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Common types of release agent:

 Neat oils with surfactants. Used mainly on steel faces, but also suitable for timber and plywood.  Mould cream emulsions. Good general-purpose release agents for use on timber and plywood.  Chemical release agents. Recommended for high-quality work, applied by spray to all types of form face.  VERA’s - vegetable, oil-based release agents are more environmentally friendly, being biodegradable water based products.

Sound formwork, properly erected in accordance with the design requirements, is an essential prerequisite of a successful casting. It is important that the supervisor should make a careful and thorough safety and accuracy inspection of the formwork before concreting starts. This inspection should provide, where applicable, satisfactory answers to the following questions:  Is the formwork erected in accordance with the approved drawings? 

Formwork  Is the formwork restrained against movement in all directions? Is it correctly aligned and levelled?  Are all the props plumb, and at the right spacing?  Are bolts and wedges secure against any possible loosening?

 Are the forms clean and free from rubbish such as tie-wire cuttings and odd bits of timber or metal?  Has a release agent been applied, and is it the correct one?  Is the reinforcement correct? Are there enough spacers, and is the depth of cover correct?

 Has the correct number of ties been used? Are they all in the right places, and properly tightened?

 Are all projecting bars straight and correctly positioned?

 Are the proprietary items compatible? Make sure that different components do not get mixed up

 Have all the toe-boards and guard rails been provided?

 Are all the inserts and cast-in fixings in the right position, and secure? Check that void formers are firmly fixed, or tied down, so that they do not float up.  Can any further inserts or boxouts be fixed during concreting if required?  Have all the stop ends been properly secured?  Have all the joints been sealed to stop grout loss - especially where the formwork is against a kicker?  Can the formwork be struck without damaging the concrete? 10

 Is there proper access for placing the concrete and compacting it?

 How will you know when to strike the formwork?  Has the curing been organized? Once the initial checks have been carried out by the supervisor, the work will normally be inspected by the clerk of works, or resident engineer, before concreting proceeds. The inspection, combined with a general check on the security and tightness of the forms, can save accidents and injuries, even loss of life.

Once concreting starts

The work of placing and vibrating can cause displacement of the forms as work proceeds, so an eye should be kept open for anything untoward happening. Tell-tale devices and stringlines should be fixed so that a continuous check can be made on alignment and plumb during the placing and vibrating operations. Grout loss is an indication that some movement has occurred (or that the joints were not fixed properly in the first place). Before a wall or column pour starts, the permitted rate of rise (in metres per hour) must be known because the formwork will have been designed to withstand a specific concrete pressure. The permitted rate of rise will be affected by the concrete, its consistence, the type of cement used and whether it contains any plasticizers or retarders and the temperature. To keep the concrete pressures acceptable on a cold day, you might have to slow down the rate of rise.

Fig 12. Look out for signs of movement especially with external vibrators

Formwork If the design pressure is exceeded, formwork will be overloaded, possibly with disastrous results. Someone experienced in the construction of formwork should always be standing by when concrete is being placed, to keep an eye open for any faults that might develop, to cope with any emergency and to carry out any necessary remedial work. A supply of suitable equipment, such as spare props and bolts, should be held on site. Any spilt concrete or grout leakage should be cleaned from the formwork as soon as concreting is completed. This is more easily done at this stage than when the forms are being put away for storage. It also makes striking easier. Early cleaning is particularly important with large formwork panels, for concrete stuck to them will add considerably to their weight. A light coating of oil on the back of any steel formwork at the start of operations will make cleaning easier.

A couple of other points to watch during concreting:  Where unsleeved tie bars are being used, ease them slightly before the concrete sets, and remove them as soon as it is safe to do so. If the bar is left unmoved, it will be difficult to avoid damage to the form or the concrete during striking.  If a non-spacing tie system is used and you have timber spreaders holding wall formwork apart, the spreaders should be removed as soon as the concrete reaches their level.

Faster striking times might be authorized by an engineer. The size and shape of the member, the characteristics of the concrete and the weather will all affect the decision on when to strike, e.g during cold weather, concrete does not harden so quickly and formwork will usually need to be left in place longer.

Fig 13. Systematic removal of the forms

Before you start to strike, make sure that a place has been allocated for cleaning the formwork, and carrying out any necessary repairs.

STRIKING THE FORMWORK

Site personnel not involved in the operation should be kept well clear to avoid any possibility of their being involved in an accident. Begin by loosening ties and clamps gradually, a little at a time, to prevent the last tie from binding.

Formwork can be struck once the concrete has gained enough strength to be self-supporting, and to carry any other loads that may be put on it. Always obtain approval before striking; the job specification will normally give guidance on this, but it might be overcautious.

As you remove bolts, ties and screws, do not just throw them to the ground in the hope that you will find them later. Put them instead in boxes. Simple plywood boxes fixed to the back of the panels are a good idea, for then the bolts and ties will travel with the forms.

Fig 14. Take care not to damage the concrete or formwork when striking

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Formwork Should the forms not immediately come away once the ties have been removed, carefully prise them loose with hardwood wedges. Do not use nail bars, they invariably damage both the concrete and the forms. If the striking is carried out within 12 to 18 hours of placing, the concrete will still be weak and thus easily damaged. Care must be taken.

or forced out of shape - a common cause of damage to formwork on site. Projecting nails left in the formwork cause untold injuries on construction sites, so check whether there are any, and remove or hammer them down.

Leave blocking-out pieces in the concrete as long as possible, since they protect the edges. Also, they eventually shrink, and then it is easier to remove them.

The method and sequence for striking soffit formwork should always be approved before you start - then strictly adhered to. It is all too easy to overload the floors of multi-storey buildings under construction if the agreed sequence is not followed.

Larger sections of formwork above ground will be lowered by crane. The craneage will be controlled by the nominated banksman using the correct code of signals to guide the crane driver.

The usual sequence is to begin by easing the supports by one turn on the prop, then start striking at midspan, working towards the walls or columns, which will progressively take the load.

Take care that the sections do not bump into scaffolding or other projections, and so get damaged, as they are lowered. Ensure too, that they come to rest on a level surface so that they are not twisted

On a cantilever, start at the end and work towards the supports. If you have a tee-beam supporting slabs on both sides, first release the slabs as already described, then strike the tee-beam, starting from the centre.

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As soon as the formwork is struck, there can be a rapid loss of moisture from the concrete surface. To make sure there is no reduction in surface strength and minimise the occurrence of a dusty surface, curing should start immediately - see Concrete onsite No 6: Curing.

Cleaning

Cleaning the face of forms should start as soon as they have been struck. A stiff brush will rid timber and uncoated plywood of dust and grout. Stubborn bits can be cleaned off with a timber or plastic scraper, rather than a steel one. On grp, other plastics and quality film-faced plywood, a brush and wet cloth are all that should be needed. If the forms are not going to be used for some time, lightly oil steel ones to stop rust from forming and coat timber and unsealed plywood with a release agent for protection. At the same time, any depressions, splits or holes should be treated with a suitable filler such as plastic wood, applied slightly proud then sanded smooth.

Fig 15. Concrete must be cured after striking

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Formwork Storage

Good storage is essential to ensure that formwork can be used again. A tidy storage area reduces the risk of damage, loss and wastage (all of which can be very expensive) and makes it easier to find the components when they are next required, thus saving time and labour. Put the forms into storage as soon as the cleaning and oiling are finished, unless they are wanted for immediate re-use. If you leave formwork lying around, it will only be damaged, or used for some other purpose. More damage happens to formwork when it is not in use than when it is being erected and struck. So take great care. Panels and plywood sheets are best stored horizontally on a flat base so that they lie without twisting. Stack them face to face to protect the faces.

USEFUL CONTACTS

Paint code numbers on them so that you can readily identify them when they are next needed. Loose walings and soldiers should also be numbered, and stored with their respective panels. Small components such as bolts, ties, wedges and keys are, as already mentioned, best stored in boxes. Larger ones e.g. clamps and propsshould be stacked off the ground. The whole of the formwork should be covered with tarpaulins or plastic sheets to protect it from the weather, with a dead air space left to ensure ventilation. Finally, fire extinguishers should be kept nearby. Check them regularly to make sure they are always in working order.

British Precast Concrete Federation www.britishprecast.org BSI Quality Assurance www.bsi-global.com Cement Admixture Association www.admixtures.org.uk Cementitious Slag Makers Association www.ukcsma.co.uk Construction Plant Association www.cpa.uk.net Meteorological office www.metoffice.gov.uk. Mineral Products Association www.mineralproducts.org Quality Scheme for Ready Mixed Concrete www.qsrmc.co.uk Sprayed Concrete Association www.sca.org.uk The Concrete Centre www.concretecentre.com The Concrete Society www.concrete.org.uk UK Cares (reinforcement) www.ukcares.co.uk UK Quality Ash Association www.ukqaa .org.uk

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Formwork FURTHER READING

BS EN 206-1: Concrete.

For information on Standards and other publications, refer to the Concrete Book Shop, www.concretebookshop.com

BS EN 12350: Testing fresh concrete.

British Standards BS 1881: Testing Concrete.

Part 113: Method for making and curing no-fines test cubes.



Part 130: Method for temperature-matched curing of concrete specimens.



Part 1: Specification, performance, production and conformity.



Part 1: Sampling.



Part 2: Slump test .



Part 4: Degree of compactability.



Part 5: Flow table test.



Part 7: Air content. Pressure methods.

BS EN 12390: Testing hardened concrete.

BS 4449: Steel for the reinforcement of concrete. Weldable reinforcing steel. Bar, coil and decoiled product. Specification.



Part 2: Making and curing specimens for strength tests.



Part 3: Compressive strength of test specimens.

BS 4482: Steel wire for the reinforcement of concrete products. Specification.

BS EN 13670: Execution of concrete structures.

BS 4483: Steel fabric for the reinforcement of concrete. Specification.

BS EN 13286-41 Unbound and hydraulically bound mixtures: Part 41: Test method for determination of the compressive strength of hydraulically bound mixtures.

BS 5975: Code of practice for temporary works procedures and the permissible stress design of falsework. BS 7542: Method of test for curing compounds for concrete. BS 7973: Spacers and chairs for steel reinforcement and their specification. BS 8443: Specification for establishing the suitability of special purpose concrete admixtures. BS 8500: Concrete – complementary British Standard to BS EN 206–1: 2000,

Part 1: Method of specification and guidance for the specifier.



Part 2: Specification for constituent materials and concrete.

BS 8666: Scheduling, dimensioning, bending and cutting of steel reinforcement for concrete. Specification.

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BS EN 14227-1 Unbound and Hydraulically bound mixtures – Specifications – Part 1 Cement bound granular mixtures.

Formwork Further reading continued.

Construction Industry Research and Information Association (CIRIA)

Building Research Establishment

Formwork striking times – criteria, prediction and methods of assessment, Report 136, 1995

Design of normal concrete mixes, 2nd ed, 1997 Formwork for modern, efficient concrete construction, BR495, 2007 The Concrete Society Technical Report 52, Plain formed concrete finishes, 1999 Technical Report 62, Self-compacting concrete, 2005 Formwork – a guide to good practice, 2nd edition, 1995 Good Concrete Guide 2: Pumping concrete, 2005 Good Concrete Guide 6: Slipforming of vertical structures, 2008 Good Concrete Guide 7: Foamed concrete, application and specification, 2009 Good Concrete Guide 8: Concrete practice, Guidance on the practical aspects of concreting, 2008

Concrete pressure on formwork, Report 108, 1985

Action in the case of non-conformity of concrete structures, Report C519, 1999 Construct Guide to flat slab formwork and falsework, 2003 A guide to the safe transportation of formwork and falsework equipment, 2005 A guide to the safe use of formwork and falsework, 2008 Health and Safety Executive (HSE) Hand-vibration – The control of vibration at work regulations, 2005 The work at height regulations, 2005 The Control of Substances Hazardous to Health Regulations, 2002

Checklist for erecting and dismantling falsework, 1999

Management of Health and Safety at Work Regulations, 1999

Checklist for assembly, use and striking of formwork, 2003

Managing Health and Safety in Construction, 2007

Concrete Advice no 16, Assessing as struck in situ concrete surfaces, 2003

The Personal Protective Equipment at Work Regulations, 1992

Concrete Advice no 20, Curing concrete, 2005

The Manual Handling Operations Regulations, 1992

Concrete Advice no 30, Identity testing for strength in accordance with BS EN 206-1 and BS 8500-1, 2007

Highways Agency, Her Majesty’s Stationary Office (HMSO)

Concrete Advice no 31, Identity testing of fresh concrete for properties other than strength, 2007

Manual of contract documents for highway works, vol 1, Specification for Highway Works

Concrete Advice no 37, Mould release agents, 2008

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Formwork Other titles in the Concrete on site series

Published by The Concrete Society OS003 Published May 2010 © The Concrete Society The Concrete Society Riverside House, 4 Meadows Business Park Station Approach, Blackwater, Camberley Surrey GU17 9AB Tel: +44(0)1276 607140 FAX: +44(0)1276 607140 www.concrete.org.uk Other publications in this series are available from the Concrete Bookshop at www.concretebookshop.com Tel: +44(0)7004 607777

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1. Ready-mixed concrete 2. Reinforcement 3. Formwork 4. Moving fresh concrete 5. Placing and compacting 6. Curing 7. Construction joints 8. Making-good and finishing 9. Sampling & testing fresh concrete 10. Making test cubes 11. Winter working