4. Formwork
ο Formwork:- is the term given to either temporary or
permanent molds into which concrete or similar materials are poured.
In the context of concrete construction, the falsework supports the
shuttering molds.
5. Types of Formwork Material
Below are the common types of formwork
material used in concrete construction:-
ο Timber
ο Steel
ο Plywood
ο Aluminum
ο Plastic
ο Fabric, Etc.
6. Timber
ο Timber is a popular formwork material. It has been using from
ancient age.
ο We can make concrete formwork using only timber or combining
timber with other types of formwork material.
ο Timber is light weight, easy to fix and remove. It's also economical
and available in different sizes.
7. Steel
ο Steel formwork materials are costly. But it has many times re-usability.
ο It's mainly useful for construction company where repeated uses are
possible.
ο Steel formwork materials give excellent finishes to concrete surface.
ο Wide variety of steel formwork materials are available in the market for
various purpose of uses.
8. Plywood
ο Plywood is an artificially manufactured wooden material used for making
concrete formwork.
ο It is strong, durable and light weight. The availability of different
thickness plywood in the market makes it popular for different sizes
concreting work. The thickness range of plywood is, from 7mm to 32 mm.
ο The standard size of plywood mostly used in building construction is 1220
x 2440mm. It can easily be cut into any size.
9. Aluminum
ο Aluminum formwork is getting popular in construction industry.
ο It is easy to fix and remove thus increase worker productivity.
ο It is also many times re-useable.
10. Plastic
ο As per experts, depending on the plastic quality, it can be used up
to 100 times.
β’ The core advantage of this is, it is super lightweight, easy to handle
and stack.
11. Design and layout of formwork
The design and construction of formwork shall take account of safety and
of the surface finish required. The formwork shall be sufficiently rigid and
tight to prevent loss of grout or mortar from the fresh concrete or the
formation of fins or other blemishes on the concrete. The contractor shall
appoint a Falsework Coordinator to carry out work on behalf of the
contractor.
12. Steps for Placing of Formwork
ο Step 1: First Take the desired slab level and mark it on column
reinforcement. Practically level is taken before column casting. So
start with that.
ο Step 2: Fix the beam bottom between columns. Weld the beam
bottom with column reinforcement. Give support to beam
bottom with steel props. Spacing of props should not exceed 2.5 feet
depending on beam span. Weld props with beam bottom to keep
the props in place.
13. ο Step 3: Now fix the inner part of beam side with beam bottom by shutter clip or nut-
bolt. Make sure foam is provided into shutter joint to make the formwork leakage
proof.
ο Step 4:Put scaffolding on base plate. Spacing of scaffolding should be maximum 4
feet. Fix cross-bar with scaffolding to keep it in place.
ο Step 5: Use joint pin to put one scaffolding above another.
ο Step 6: Now start laying 4"x4" MS hollow box on U-head. Spacing of runner should
not be more than 4 feet center-to-center. At this stage level the hollow boxes by
adjusting U-head in accordance with marked slab level.
Steps for Placing of Formwork
14. ο Step 7: After all big runner are leveled then start laying
small runner (1.5β x 1.5β MS hollow box) perpendicularly on
big runner. The center-to-center distance of small runner should
not exceed 1 feet.
ο Step 8: Check the slab level all around again with water level.
ο Step 9: Now start laying plain sheet on top. Lapping between
plain sheets should be minimum 2 inches. Keep in mind that If
you place plain sheet parallel with small runner then keep
every sheet joints directly on small runner
Steps for Placing of Formwork
15. ο Step 10: Now make the sheet jointer proof with masking tape.
ο Step 11: Apply oil to all shutter faces which will contact with concrete to avoid
sticking concrete with form. You can use any shutter oil for this purpose. But I found
1:10 Mobil-diesel mix is better.
(Note:- Steps for placing formwork are not fix. Steps for formwork depends upon
activity i.e. Beam, Slab, Column and their type and on type of formwork. Step of
formwork may or may not vary.)
Steps for Placing of Formwork