Removal of Forms
Forms should not be removed until the concrete has sufficiently hardened in order that it can carry safely its own weight and any other live loads it is subjected to.
The supporting period (period between placing of concrete in forms and removal of forms) differ according to the type of cement used and the design of formwork. In general structures carrying construction loads, side timbers shall not be removed within 7 days and supporting timbers within 28 days of placing of concrete.
In no circumstances shall forms be stuck until the concrete reaches strength of at least twice the stress to which the concrete may be subjected at the time of striking.
The strength referred to shall be that of concrete using the same cement and aggregates, with the same proportions, and cured under conditions of temperature and moisture similar to those existing on the work. Where possible, the formwork should be left longer, as it would assist the curing.
In normal circumstances (generally where temperatures are above 200C), and where ordinary cement is used, forms may be struck after expiry of following periods.
| Type of Form | Removal Time Period |
| Walls, columns and vertical sides of beams | 24 to 48 hours as may be decided by the engineer-in-charge. |
| Slabs (props left under) | 3 days |
| Beam soffits (props left under) | 7 days |
| Removal of props to slabs (Spanning upto 4.5 m) | 7 days |
| Removal of props to slabs (Spanning over 4.5 m) | 14 days |
| Removal of props to beams and arches (Spanning upto 6 m) | 14 days |
| Removal of props to beams and arches (Spanning over 6 m) | 21 days |
For rapid hardening cement, 3/7 of the above period will be sufficient in all cases except vertical sides of slabs, beams and columns which should be retained for 24 hours.
All formworks should be removed without shock or vibration as this would damage the reinforced concrete. Before the soffit and struts are removed, the concrete surface should be exposed, where necessary in order to ascertain that the concrete has sufficiently hardened. Proper precautions should be taken to allow for the decrease in the rate of hardening that occurs with all elements in the cold weather.
Reference
IS-456 – Plain and Reinforced Concrete – Code of Practice
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Hi please if a concrete vibrate when the form work is removed is a form of what please ?
Can we strip the Girder,Beams,& Slab forms if the design concrete strength was already met?
What is the removal period of formwork for footings
what is the material / technical specification (i.e. thickness) of left in formwork?
(props left under) what do you mean by this.
How many days after casting the slab we can remove shuttering.
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minimum 14days if thr length of beam is smaller than 4m
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How many day to take segments arch with bricks to dry so as to remove the support structure under its
Hi, You should gently release the wedges to the arch centre the next day and keeping the arch centre in position lower it a few millimetres. This will allow the mortar between the bricks to compress and increase the bond strength with the surrounding masonry.
Gentleman,
(1) What time I can remove shuttering from “Horizontal Beam” for my new house construction
(2) and overall slab time also
Regard
Muhammad Safdar
Riyad
How many days after swimming pool shuttering removed
is it good to remove formwok after 4 hours from column. I am using OPC cement and weather temperature is high.
The concrete is the most toughest thing and too hard to remove. These tips can surely be used to take the framework of the concrete be removed. So now it can be removed easily.
i am building a rcc tank 2 lakh litres. its height is 2.5metres. i am going first for its side upto 1.2m in the first step. can i remove the form work in a day and go for the next step.??8
I think there is a mistake in the striking time for Vertical formwork to Columns, walls, Beams is 16 to 24 hrs instead of 24 to 48 hrs as you have mention in your blog.
best Regards
Ali
How many days after concrete we can remove foam works of dome?
While filling the RCC column (with Box) with concrete, should it be filled to the full height of the column in one stretch? The common domestic construction practice is the column box is mounted ti half the height of the column filled with concrete on one day, and box is dismantled after setting and again mounted up to remaining top half and filled with concrete on another day.
Is it a correct practice?
My doubt is that will there be proper bonding between the already set concrete layer with the concrete poured over that then.
Request clarification from Civil Engineers please
prithvi , I am civil engg. but as per my thinking you should go for single fill of column e.g 7 or 8 feet rather than two half fills if appropriate size firma is available and have longer vibrator reach. 4 feet firma plates are more commonly available and so are 1.5m (5 feet) vibrators. make sure the condition of firma plates is good and no broken backing strips so that you can get better vertically straight columns. cost of 5 feet vibrator is 3500 in Mohali/Punjab and 6m set is around 10,000.
On joint front, you will always have joints here or there, the whole building will not be casted in single go. so avoid if possible but not to be feared.