The role of formwork during the construction
The purpose of Aluminum Formwork is to maintain and contain fresh concrete until it hardens
and give it the desired shape. Formwork is the essential tool in the construction of concrete
structures. It must give its final shape to the concrete while respecting the execution tolerances. It
must withstand the loads induced by the own weight of the concrete during its pouring and
control deformations (respect for the arrows of the floors, for example). It must make it possible
to carry out the operations of placing the reinforcements and vibrating the concrete. On-site, the
tools used for molding concrete are formwork.
In case of vertical walls and sails, these forms called shutters have given base to the structure,"
which refers to concrete poured into shutters. The formwork is built in Formwork System
manufacturers in India. It is designed to meet the rotation cycles defined by the method
department of the company by integrating many requirements: the size of formwork, location of
reinforcements, and the principle of shoring.
Formwork design
Column Formwork must have sufficiently rigid and stable to withstand the thrust of fresh
concrete especially in the case of fluid or self-consolidating concrete. It must support
construction, without deforming, including during the vibration phase, and ensure the
maintenance of the concrete until it sets and hardens.
A good framework must be non-absorbent, be stable to guarantee safety on the site. Be airtight to
prevent leakage of laitance, in particular at the foot of the formwork and at the joints, and at the
adjustment of the mannequins. These frames must be able to obtain the desired surface texture to
meet architectural requirements, in particular, be "unblock able" so as not to damage the concrete
when stripping. In particular, in the event of frequency reuse, the deterioration of certain types of
formwork (in particular wood) is likely to modify their mechanical and dimensional
characteristics as well as the final appearance of the concrete.
Note: when designing the Slab Formwork, the remolding phase must be taken into account in
order to avoid rework, which is difficult to repair. The forms have openings or open angles must
be released easily. The choice of formwork depends on the work, the complexity of the form to
be produced and the number of its reuses. We can nevertheless identify a number of common
requirements that it must meet.
Undeformability and stability
A formwork must not deform under the effect of the thrust of the concrete and during its
vibration. Compliance with the dimensional tolerances of the structure depends directly on this
criterion.
The design of the formwork must, therefore, endeavor to respect this and stability by considering
the static pressure exerted by the concrete. In common cases 2 to 6 t / m2 is sufficient depending
on the height of the concreting and the dynamic stresses resulting from the vibration. This varies
according to the mode of vibration and the type of vibrators. The formwork must also be stable
in comparison with the forces of wind and possible shocks.
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