CONSTRUCTION TECHNOLOGY

Presented by :Felix Vong Zhi Wei 0318462Aaron Ngu Nguok SoonLim Chu Ning Chen Shin Yee 0322650

FORMWORK?

• Support structure and moulds to create structures out of concrete.• Made by using steel, wood, aluminium and prefabricated forms.• Cost of formwork is about 30%-40% of the concrete cost.

Do you know…Reusable forms known as

panel forms&

Non-reusable forms known as stationery forms

FORMWORK?

• A good formwork - Water tight - Strong - Reusable• Major considered in formwork - Quality; sufficient and accuracy of the size, shape and position. - Safety; sufficient strength and factor of safety. - Economy; built efficiently, minimizing time and cost.

A good formwork should satisfy the following requirements :

1. It should be strong enough to withstand all types of dead and live loads.2. It should be rigidly constructed and efficiently propped and braced both horizontally and

vertically, so as to retain its shape.3. The joints in the formwork should be tight against leakage of cement grout.4. Construction of formwork should permit removal of various parts in desired sequences

without damage to the concrete.5. The material of the formwork should be cheap, easily available and should be suitable for

reuse.6. The formwork should be set accurately to the desired line and levels should have plane

surface.7. It should be as light as possible.8. The material of the formwork should not warp or get distorted when exposed to the elements.9. It should rest on firm base.

FORMWORK FOR COLUMN• It consists of the

following - Side & End Planks - Yoke - Nut & Bolts• Two end & two side

planks are joined bt the yokes and bolts.

COLUMN FORMWORK

• Function :1. Enable the construction of columns have the specified surface

quality.2. Acceptably accurate in shape and position with good alignment to

other adjacent columns, walls and building facades.

• Constructed with the columns reinforcement must extending well above the form

So it can lap with the reinforcement of the next column or floor.

COLUMN FORMWORK CONSTRUCTION• Most column forming methods use plywood to form faces.• The corner junctions of the plywood must be detailed to achieve the

maximum tightening action from the column clamps.• Timber angle fillets are used to form the arise.

CIRCULAR COLUMN FORMWORK-Fabricated steel, usually two pieces, with bolted joints.

-Timber sheathing tied with standard column clamps, corner need to have wedges to to support. For larger columns

-Cardboard tube, one-off formwork, available in a range of diameters. Cut to waste after concrete is poured.

COLUMN FORMWORK CONSTRUCTION STAGES• Column formwork bracing• Column formwork bracing performs TWO function : 1. Maintain the accuracy of the column form position and plumb.2. With stand results of forces acting on either the column formwork

or the bracing.

BEAM FORMWORK

• Beam formwork must be thickened timber or strengthened plywood• Deep beams should have waters

and ties.• Props or falsework must be placed

under the headtree or bearers, and must spaced to suit the weight of concrete.

Erection sequence for constructing beam formwork1. Position of sole plates.2. Marking out and setting heights for falseworks. 3. Assemble and position props, adjustable head jacks, falseworks,

bearers and spreaders.4. Construct and erect side walls and beam formwork.

STEEL FORMWORK

• This consists of panels fabricated out of the thin steel plates stiffened along the edges by small steel angles.• The panel units can be held together through the use of suitable

clamps or bolts and nuts.• The panels can be fabricated in large number in any desired modular

shape or size.• Steel forms are largely used in large projects or in situation where

large number reuses of the shuttering is possible.• This type of shuttering is considered most suitable for circular or

curved structures.

STEEL FORMWORKSteel formwork is made of - Steel sheets - Tee iron

- Angle iron

• For heavy concrete work• With reasonable care will last indefinitely• High initial cost and high handling cost

Advantages of steel formwork• It can be used for a no. of times.• It is non absorbent.• Smooth finish surface obtained.• No shrinkage of formwork occurs.• Easy to use.• Its volume is less.• Its strength is more.

Disadvantages of steel formwork

• Limited size or shape.• Excessive loss of heat.• A very smooth surface will be

produced which would give problems for finishing process.• Limited fixing.

ALUMINIUM FORMWORK

• Manufactured using light weight aluminium.• Made up of aluminium metal frame that provides very sturdy and

durable mold for pouring concrete.

ADVANTAGES OF ALUMINIUM FORMWORK• Quickly and accurately assembled.• Reduces the labour cost owing to its easy installation.• Light weight component provides low pressure on the lower part of the buildings.• Aluminium metal surface offers easy cleaning after concrete is removed.• Faster construction cycles.• Easy to handle.• High quality finishes.• Can be easily recycled.• Can be repeatedly used without losing quality • Safe work platforms.• High salvage cost.• Fewer burdens on environment.

DISADVANTAGES OF ALUMINIUM FORMWORK• Initial high investment.• Compares very poorly on modifications, against brick work

constructions.• Fear of theft of valuable Aluminium Extrusions & sheets & hence kit

not being complete at critical stages of construction.• Mass Housing projects are not as high for investing in large number of

Aluminium Formwork.

TIMBER FORMWORK

Material used : • Most common material used for

bracing the member, hence called as the traditional formwork.• Can easily be cut to size on site.

Joist are replaced with engineered wood beams and supports are replaced with metal props. This makes this method more systematic and reusable.

ADVANTAGES OF TIMBER FORMWORK• Easy handling because it is light weight.• Easy to disassemble.• Damaged parts can be replaced with new one.• Very flexible.• Easy to produce.• Easily available.

DISADVANTAGES OF TIMBER FORMWORK• Limited size of shape.• Excessive loss of heat.• A very smooth surface will be produced which would give problems

for finishing process.• Limited fixing.

SLAB FOUNDATIONS

• A slab foundation is an extension of a slab floor.• Cast when the floor is placed.• Sometimes called thickened edge slab.• Should extend below the frost line.• Reinforcement is recommended.• Advantages : - required less time

- labor - expense to construct

PLYWOOD FORMWORK

• Most common material used for the facing panel.• Easily cut to shape on site.• Reusable.• Thinner plywood is used to facilitate bending.• Thicker plywood is used when the weight of concrete caused a

standard thickness plywood to blow out, it might distorting the concrete face.

PLYWOOD FORM ( IN COMBINATION WITH TIMBER )• Concrete shuttering plywood is bwp grade plywood, preservative

treated and specially suited for use in concrete shuttering and formwork.• The plywood is built up of odd number of layers with grain of

adjacent layers perpendicular to each other.• Plywood is used extensively for formwork for concrete, especially fpr

sheathing, decking and form linings.• There are two types of plywood – internal and exterior.• The interior type is bonded with water resistant glue and exterior

type is bonded with water proof glue.

PLASTIC FORMWORK

• These forms have become increasingly popular for casting unique shapes and patterns being designed in concrete because of the excellent finish obtained requiring minimum or no surface treatment and repairs.• Different types of plastic forms are

available like glass reinforced plastic, fiber reinforced plastic and thermoplastics etc.

Fiberglass-reinforced plastic is the most common and has several advantages such as • The material allows greater freedom of design.• Unusual textures and designs can be molded into the form.• It allows the contractor to pour structural and finished concrete • Simultaneously – because sections can be joined on the job site in

such a way so as to eliminate joints, there is no size limitation. If carefully handed, a number of reuses are possible making it highly.• Economical – it is lightweight and easily stripped.

~THE END~