Presentation on Formwork shuttering for concrete structure and its design
I have attached herewith the presentation on Formwork shuttering and its design along with photographs, the presentation includes following topics;
Formwork is a mould or open box, like container into which fresh concrete is poured and compacted.
When the concrete is set, the formwork is removed and a solid mass is produced in the shape of the inner face of the formwork.
The top of the formwork is normally left open.
Falsework is the necessary support system that holds the formwork in the correct position.
Formwork for concrete structure should be;
Formwork Economy
Formwork materials can be classified as:
1. Timber
2. Metals
3. Plastics
Timber Formwork
Lumber:
Lumber is commonly available material and has excellent strength, weight and cost factor.
Lumber is classified as:
Boards: 1 to 1.5 inches thick, 2 or more inches width
Dimensions: 2 to 4 inch thick, any width.
Timbers: 5 or more inches thickness, 5 or more inches width
Plywood
The use of plywood in concrete forming for form facing has improved the quality of finished concrete.
The relatively large sheets of plywood have reduced the cost of building and at the same time have provided smooth surfaces that reduces cost of finishing of concrete surfaces.
PIywood is a manufactured wood product consisting a number of veneer sheets, or plies
Type of plywood can be grouped as exterior and interior. For formwork the exterior plywood is used. Adhesive used to bond the piles in manufacturing of exterior plywood is watertight and gives maximum number of reuses.
Metal Formwork
The initial cost of metal formwork is more than timber formwork but the number of reuses of metal formwork is higher than that of timber.
in long run metal formwork can be economical.
İn heavy construction works metal formvvork may require a lifting mechanism to handle the formvvork panels or props.
Steel sheet formvvork has the problem of rusting also. To avoid rusting, in every use the surfaces should be oiled with an appropriate releasing agent.
in metal formvvork usage, the metal sheets are prepared as panels of standard sizes. This brings the difficulties of erecting irregular dimensions of formwork.
Steel or aluminum or magnesium is the most widely used metals.
Plastic Formwork
They have impervious surfaces that usually create a smooth finish to the concrete.
Plastic formwork could be reinforced or un-reinforced.
Plastic is reinforced by glass fibers.
Reinforced plastics are specially produced for a specific formwork type.
Un-reinforced plastics are produced in sheet form with smooth or textured surfaces.
Plastic formwork is lighter but less durable than metal formwork.
Formwork Types by shape
Considering shapes, formwork can be classified as:
Column Formwork
Beam formwork
Slab Formwork
Wall Formwork
Column Formwork
Column formwork is made usually with either timber or metal panels.
The principle is to create an enclosed box with frames at the exact size of the column and fix it tightly on the kicker left from base or at the last stage of column concreting.
The box is held in position by steel column clamps or bolted yokes and supported by timber studs or props
Beam Formwork
Beam formwork consists of open through section and because it is not closed at the top requires more supporting framework to restrain the sides.
The supports need to be maintained to the soffit and also provide lateral support to the sides.
In timber this is done by the use of a head tree across the top of a vertical member.
Metal panels are used with corner pieces, but timber head trees are needed for vertical support.
Slab Formwork
Floors require a large area of formwork to be provided usually from beam to beam.
Timber floor formwork consists of timber boards or plywood sheets supported on a framework and resting on a series of timber joists.
Again timber and metal props can be used for vertical supports.
Metal panels can be used and bolted or clipped together and held in place by a system of metal beams or a tabular scaffold system.
Adjustable props need for levelling purposes
Wall Formwork
Wall formwork is a simpler than for other concrete units as the actual forces against it are less, most of the load being carried vertically downwards.
The panels at both sides are held in position by ties.
Ties are also used as spacer, arranging wall thickness. systems are usually sloping
Wall support props at satisfactory intervals.
Formwork Striking times
The time to be allowed before formwork can be removed naturally depends on many factors, such as:
1.The type of concrete mix used (type of cement) Rapid hardening cement mix requires less time, whereas high water cement ratio needs longer time for striking the formwork.
2.The type of structural member being cast Soffit of beams and slabs or sides of beams or columns require different time.
3.Temperature High temperature can cause rapid curing of concrete and formwork can be struck in shorter time than low temperature weather.
It consist detailed information on following;
British Standards Formwork Striking Times
Turkish Standard Formwork Striking Time
Formwork ties specifications and details
Design of Wall and Column formwork
You can download the presentation from below attachment.
I have attached herewith the presentation on Formwork shuttering and its design along with photographs, the presentation includes following topics;
Formwork is a mould or open box, like container into which fresh concrete is poured and compacted.
When the concrete is set, the formwork is removed and a solid mass is produced in the shape of the inner face of the formwork.
The top of the formwork is normally left open.
Falsework is the necessary support system that holds the formwork in the correct position.
Formwork for concrete structure should be;
- Strong enough to resist the pressure or the weight of the fresh concrete plus any constructional live loads.
- Rigid enough to retain the shape without undue deformation.
- Economical in terms of the total cost of the forms and the concrete surface finishing when required.
- Sufficiently watertight to avoid leakage at the joints.
Formwork Economy
- In order to reduce the cost of formwork for concrete structures the following are to be considered:
- Design the formwork to provide adequate but not excessive strength and rigidity.
- Fabricate the forms into modular sizes to provide more reuses without refabricating when practical.
- Prepare working drawings prior to fabricating the forms.
- Prefabricate form sections on the ground rather than on scaffolding.
- Use the most economical formwork material considering the initial cost and reuses.
- Use no more nails than are needed to join the forms together safely.
- Remove the formwork as soon as it is permissible.
- Clean and oil forms by using releasing agent after each use.
- When it is permissible install construction joins to reduce the total quantity of form material required and permit the carpenters to work more continuously.
Formwork materials can be classified as:
1. Timber
2. Metals
3. Plastics
Timber Formwork
Lumber:
Lumber is commonly available material and has excellent strength, weight and cost factor.
Lumber is classified as:
Boards: 1 to 1.5 inches thick, 2 or more inches width
Dimensions: 2 to 4 inch thick, any width.
Timbers: 5 or more inches thickness, 5 or more inches width
Plywood
The use of plywood in concrete forming for form facing has improved the quality of finished concrete.
The relatively large sheets of plywood have reduced the cost of building and at the same time have provided smooth surfaces that reduces cost of finishing of concrete surfaces.
PIywood is a manufactured wood product consisting a number of veneer sheets, or plies
Type of plywood can be grouped as exterior and interior. For formwork the exterior plywood is used. Adhesive used to bond the piles in manufacturing of exterior plywood is watertight and gives maximum number of reuses.
Metal Formwork
The initial cost of metal formwork is more than timber formwork but the number of reuses of metal formwork is higher than that of timber.
in long run metal formwork can be economical.
İn heavy construction works metal formvvork may require a lifting mechanism to handle the formvvork panels or props.
Steel sheet formvvork has the problem of rusting also. To avoid rusting, in every use the surfaces should be oiled with an appropriate releasing agent.
in metal formvvork usage, the metal sheets are prepared as panels of standard sizes. This brings the difficulties of erecting irregular dimensions of formwork.
Steel or aluminum or magnesium is the most widely used metals.
Plastic Formwork
They have impervious surfaces that usually create a smooth finish to the concrete.
Plastic formwork could be reinforced or un-reinforced.
Plastic is reinforced by glass fibers.
Reinforced plastics are specially produced for a specific formwork type.
Un-reinforced plastics are produced in sheet form with smooth or textured surfaces.
Plastic formwork is lighter but less durable than metal formwork.
Formwork Types by shape
Considering shapes, formwork can be classified as:
Column Formwork
Beam formwork
Slab Formwork
Wall Formwork
Column Formwork
Column formwork is made usually with either timber or metal panels.
The principle is to create an enclosed box with frames at the exact size of the column and fix it tightly on the kicker left from base or at the last stage of column concreting.
The box is held in position by steel column clamps or bolted yokes and supported by timber studs or props
Beam Formwork
Beam formwork consists of open through section and because it is not closed at the top requires more supporting framework to restrain the sides.
The supports need to be maintained to the soffit and also provide lateral support to the sides.
In timber this is done by the use of a head tree across the top of a vertical member.
Metal panels are used with corner pieces, but timber head trees are needed for vertical support.
Slab Formwork
Floors require a large area of formwork to be provided usually from beam to beam.
Timber floor formwork consists of timber boards or plywood sheets supported on a framework and resting on a series of timber joists.
Again timber and metal props can be used for vertical supports.
Metal panels can be used and bolted or clipped together and held in place by a system of metal beams or a tabular scaffold system.
Adjustable props need for levelling purposes
Wall Formwork
Wall formwork is a simpler than for other concrete units as the actual forces against it are less, most of the load being carried vertically downwards.
The panels at both sides are held in position by ties.
Ties are also used as spacer, arranging wall thickness. systems are usually sloping
Wall support props at satisfactory intervals.
Formwork Striking times
The time to be allowed before formwork can be removed naturally depends on many factors, such as:
1.The type of concrete mix used (type of cement) Rapid hardening cement mix requires less time, whereas high water cement ratio needs longer time for striking the formwork.
2.The type of structural member being cast Soffit of beams and slabs or sides of beams or columns require different time.
3.Temperature High temperature can cause rapid curing of concrete and formwork can be struck in shorter time than low temperature weather.
It consist detailed information on following;
British Standards Formwork Striking Times
Turkish Standard Formwork Striking Time
Formwork ties specifications and details
Design of Wall and Column formwork
You can download the presentation from below attachment.
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