In this construction video tutorial, Sami Ullah, the eminent civil engineer, 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.
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.
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.
Watch the following video, to get the complete information.
Image Courtest: Sami Ullah