Ten frequently asked questions about wall formwork (part 2)
After having seen the first five questions about wall formwork, we complete the second part of the questions.
Discover them with us!
6.- How many square meters of formwork can be transported with a lorry or trailer?
The amount of transportable square meters is extracted from a parameter called volumetric weight, which relates the weight to the volume of the equipment to be transported and is used to quantify transport costs.
7.- What should be taken into account when working with SCC (Self Compacting Concrete)?
Self Compacting Concrete is more fluid than other types of concrete usually used on site. It is used in cases in which a very good finish is required, or when concrete vibration is to be avoided due to time saving or because it is not possible to do it, for example in the case of some structural components that have little space between the reinforcement.
When using this type of concrete, it is important to be very careful with the pressures that the formwork receives, since this greater concrete fluidity implies a very significant increase in its pressure, by increasing its hydrostatic behavior. In case of elevated heights, such as to exceed the admissible formwork pressures, the following actions can be taken:
- Slow down and control the filling speed as indicated by the formwork supplier.
- Reinforce the formwork by means of a previous calculation, developed together with the formwork supplier’s technical service.
8.- How many square meters of formwork can I handle at once with the crane?
The number of panels that can be handled with a crane depends on two factors:
- The load-bearing capacity of the crane at the point of handling;
- The weight of the equipment to be moved.
So the calculation to be performed is easy: It must be verified that the weight of the square meters of panels to be moved is less than the load-bearing capacity of the lifting equipment at that point.
Special attention must be paid to two aspects:
- The load-bearing capacity of the crane at the handling point; the greater the distance between the loading point and the base of the crane, the lower its load capacity.
- Lifting brackets: Panels or sets of panels should always be moved with at least two crane hooks: Safety during handling is a priority.
9.- Is it possible to use external vibrators on walls?
Yes, for concrete compaction, external vibrators are a possible alternative to ad ago vibrators. However, the following aspects must be taken into account:
- Require an ad-hoc Their positioning, the optimum quantity and the handling of the equipment during filling must be studied.
- They have a higher cost than the classic vibrators.
They require compressed air equipment (if pneumatic vibrators are used) or an electric generator (if electric vibrators are used).
10.- How often should the phenolic panel of the formwork be changed?
Also in this case, the change of phenolic formwork depends on the use that is made on site and the quality objective that is desired in the finish.
What does the durability of the phenolic depend on?
- The thickness of the phenolic resin, which usually varies between 15 mm and 18 mm.
- The correct use and application of the release agent before each concreting. If not properly applied, the risk is that the phenolic resin part will tear on contact, damaging it conspicuously.
- The care with which the panel is handled on site: sometimes phenolic resin panels are damaged by accidental blows that generate holes.
- Storage conditions: The panels should not be stored in humid places or under direct atmospheric conditions. This could generate excessive water absorption in the phenolic resin, or the wood might dry out (under the sun).