De-Shuttering Of Formwork Or Formwork Removal Time
In
this Article I will show you that what is the formwork removal time Or
De-shuttering of formwork in detail.
Briefly
explains the process required for de-shuttering of formwork as well as the time
period to remove the formwork from column, walls, beam, slab, staircase,
foundation footing etc.
Removal of formwork:
The
timing of removal of formwork can depend on the rate of strength gain of
the concrete. and we can remove the formwork with different days.
(a)
Vertical surfaces can be struck when the concrete is strong enough to resist
the adhesion on the concrete/form face surface.
(b)
Soffits cannot be struck until the concrete has gained sufficient strength for
the element to support is self weight for all or part of the structural span.
It is possible to speed up the removal of much soffit formwork by removing a
small part of the formwork and then installing props to this area. Another area
of formwork can then be removed and props installed props. This sequence can be
repeated until all the formwork has been removing and the soffit is fully
propped.
The removal of concrete formwork is also known as
strike-off or stripping of formwork. It is should be performed when the
concrete obtains adequate strength.
The formwork should, under no circumstances, be
allowed to be removed until the concrete reaches strength of at least twice the
stress to which the concrete may be subjected to at the time of removal of
formwork.
While removing formworks, the following points
should be taken into consideration.
• freeze thaw damage • development of cracks
because of thermal contraction of concrete
Special consideration should be given for formwork
removal of flexural members like beams and slabs because these members are
dependent on self-load and live load even throughout construction, they may
deflect if adequate strength is not obtained to manage the loads.
Detail
information is given below.
For column/walls, vertical form works should be
detached after 16 to 24 hours.
Soffit formwork to slab (formwork is located under
the slab), the form works can be removed after 3 days. (Props should be
reaffixed once the removal is done).
Soffit formwork to beam, the form works can be
removed after 7 days. (props should be reaffixed once the removal is done.)
Beam that spans up to 4.5 m (length), the form
works can be removed after 7 days.
Beam that spans surpassing 4.5 m (length), the form
works can be removed after 14 days.
For footing, the form works can be removed after 16 to 24 hours.
For staircase, the form works can be removed after 5 days.
For footing, the form works can be removed after 16 to 24 hours.
For staircase, the form works can be removed after 5 days.
These are the removal of formwork time which should
be removing in the above days which i have discussed with you. if you remove
the formwork before the removal days , than it will be make many problems for
the structure. Therefore we should remove with the fix days.
Note: The above days to remove the formwork I have
taken from IS codes and these are the actual days by which we can remove the
formwork, in these days the concrete can gain the twice strength, which are
required for our design project.
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