Steel formwork

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Construction Technology

Transcript of Steel formwork

STEELFORMWORK

Construction Technology iv

MOHD SUFIAN ABDUL RAHIM 2010536105

HIDAYAT BIN ZAMRI 2010108475

MUHAMMAD REDZUAN BIN ZULKIFLI 2010344265

MUSAHIDDIN BIN MD ZAINAL 2010740055

XYFUL QAREEM ALZIFF BIN RIZUWAN 2010124671

Formworks• Forms are molds to receive concrete in its’ plastic form.• Formwork is temporary structure, as such, it is not

normally shown on the drawings.

Formwork for Beams and Slabs

Definition• Its is an artificial support provided below and around the

precast or cast in situ concrete work.

• Formwork is commonly made of • Steel• wood

• Formwork construction & casting is of prime importance in concrete industry. It share a significant amount of concrete cost.

Qualities of formwork

• It should be water tight

• It should be strong

• It can be reusable

• Its contact surface should be uniform

• It should be according to the size of member.

Types of formwork• Formwork are mainly of two types

• Steel formwork• Wooden formwork

• Steel formwork is made of • Steel sheets• Angle Iron• Tee Iron

• Wooden formwork consists of • Props• Planks battens• Ledgers• sheeting

• Temporary Structure

- Temporary structure required to safely support concrete until it reaches adequate strength.

• Permanent Structure

-Permanent formwork remains in situ for the life of the building

Steel Formwork• This consist of panels fabricated out of 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.

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

The first floor circular columns were constructed using steel column forms. The steel column form should be oiled before concreting.

After concreting to the first floor columns, the steel column forms were dismantled easily.

Compared with timber formwork

• Steel forms are stronger, durable and have longer life than timber formwork and their reuses are more in number.

• Steel forms can be installed and dismantled with greater ease and speed.

• The quality of exposed concrete surface by using steel forms is good and such surfaces need no further treatment.

• Steel formwork does not absorb moisture from concrete.• Steel formwork does not shrink or warp.

STEEL FORMWORK AND ACCESSORIES

• Steel formwork systems for every size and shape of ground plan, in practical dimension & equipped with different features to make shuttering more efficient.

Flatform Panels Form Work

Column Formwork

Application of Push-pull Prop. & Soldier System

Flat Form

Flat Form is used for forming planes such as those of Square columns, walls, slab floors, etc. By combining units of various sizes, flat form can be made to serve a wide variety of purposes.

Corner Angle Outside Corner Form

Inside Corner Form "L" - type pin & U-clip

Steel Form for CornersForm can be assembled easily and tightly by using the Corner Angle, Outside Corner Form & Inside Corner Form.We can tailor-made various sizes of corner to suit customer specific requirements & application.

Samples of Box Culvert DesignA combination of the Flat form Panels & corners are illustrated in the

application of common Box Culvert.

Versatile : complete systems made to meet the needs of contractors; Easy to Use : quick assembly & fixing Proven Design : fabricated for tough working conditions

Removal of formwork

• Time of formwork removal depends on the following factors

1. Type of Cement

Rapid hardening cements require lesser time as compared to OPC (Ordinary Portland Cement)

2. Ratio of concrete mix

Rich ratio concrete gain strength earlier as compared to weak ratio concrete.

3. Weather condition

Hydration process accelerates in hot weather conditions as compared to cold and humid weather conditions.

Time of Removal of formworkSr. No Structural Member

OPC (Ordinary Portland Cement)

Rapid Hardening Cement

1 Beam sides, walls & Columns 2-3 Days 2 Days

2 Slab (Vertical Supports remains intact) 4 Days 3 Days

3 Slab (Complete Formwork removal) 10 Days 5 Days

4 Beams (Removal of Sheeting, Props remains intact)

8 Days 5 Days

5 Beams & Arches (Complete formwork removal) (up to 6 m span)

14 Days 5-8 Days

6 Beams & Arches (Complete formwork removal) (more than 6 m span)

21 Days 8-10 Days

Maintenance of formwork

• Due to continuous use wooden planks & steel plates surfaces become uneven and require maintenance.

• For wooden formwork use cardboard or plastic fiber board. Bolt hole places must also be repaired.

• For steel formwork plates must be leveled by mallet and loose corners must be welded.

Advantages ofsteel 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 ofsteel 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