Differences Between Formwork and Falsework

~~Floor slab formwork~~

Formwork

~Classic temporary structure in the sense that it is erected quickly, highly loaded for a few hours during the concrete pour and within a few days disassembled for the future reused.

~Formwork for in situ concrete may be described as a mould or box into which wet concrete can be poured and compacted.

~Manufactured on site example timber or plywood and purchased such as metal or aluminium.

~Divided into two categories:

1. Temporary formwork- leave at site while concrete still wet and strike off when the concrete can support itself.
2. Permanent formwork- still leave at site even the concrete can support itself.

~Types of formwork are divided into four categories such as foundation formwork, column formwork, slab formwork and beam formwork.

~To be successful in its function must fulfill the requirements as below:

1. Should be strong enough to support load of wet concrete (generally approximately 2400 kg/ m3).
2. Must not able to deflect under load, which includes the loading of wet concrete, self-weight and superimposed loads.
3. Must be accurately set out.
4. Have grout- tight joints.
5. Form sizes should be designed so that they are the maximum size which can easily be handled by hand or by a mechanical lifting device.
6. Material must be chosen so that it can be easily fixed using either double- headed nails, round wire nails or wood screws.
7. The design of the formwork units should be such that they can easily be assembled and dismantled without any members being trapped.

~The general designs are strong, stable and leak proof.

~Selections of a formwork methods:

1. Easy to strike off or removable.
2. Can be reused.
3. Consistent surface finish.
4. Specification.
5. Method of hoisting.
6. Material and labour availability.
7. Fixing required.

~~Falsework on ground floor slab supporting formwork for suspended slab~~

Falsework

~Is that part of formwork which supports the forms.

~In civil engineering, the heights and weights encountered are normally in excess of standard propping facilities and some form of scaffolding is used.

~Three basic types of scaffold which can be employed in falsework:
1. Scaffold tubes and fittings
2. Prefabricated systems
3. Specially designed falsework in the form of prefabricated units.

~The first two types were initially designed for the access scaffolding market but have been used increasingly for falsework.

~The third type prefabricated tubular units is available from any the formwork and scaffolding specialists.

~The advantages and disadvantages units used are depends on types of the falsework.

~Tube and fittings used as falsewrk provide the most versatile material available although unlikely to be the most economic meaning the labour in erecting and dismantling is very high compared with unit systems.

~Prefabricated systems initially designed for simple access scaffolding have made a great impact on the falsework market.

~The systems usually consist of vertical frames, which are linked together by a patent bracing system; this form of linking can be visually inspected to ensure stability whereas normal tube fittings cannot be checked by the same method.

~Proprietary systems of decking including telescopic beams or prefabricated beam are often linked with falsework systems.

~The prefabricated systems therefore offer simplicity of erection coupled with a built- in grit, which give high control of components spacing.

~Prefabricated falsework are made from larger diameter tube and are capable of carrying heavier loads than the normal scaffold units.

~These systems are used extensively for supporting bridges and other heavy structure, which require variable falsework.

~Typical falsework structure such as super- slim soldier and erection of scaffolding falsework

References

Introduction to Civil Engineering Construction
Roy Holmes

Construction Technology 2
Chudley