A Professional Handbook on Formwork Techniques

Purpose and Use of Formwork

Formworks are the structures that serve to provide the support and shape for the concrete cast. When the formwork is done according to the desired specifications, it efficiently carries the cast concrete, which takes the shape of the formwork. In other words, the formwork is the mould for different structural components of concrete according to the needed structural elements and the soil.  The concrete mixture is poured into the formwork while it is still viscous, and then as it dries up, it takes the shape of the formwork.

The framework must already be on the ground by reinforcing the structure with the steel and concrete mix. The making of the formwork also depends on the accuracy of the measurement to several properties. The properties include strength, size, and the surface finish of the components of the concrete. A formwork is also essential in monolithic concrete or reinforced concrete structures such as the following. 

  • Solid standing structures like the foundations and column casts
  • Design for special functions such as chimneys, containers, and hydraulic structures
  • Systems that meet specific specified static requirements such as bridges and towers
  • The reconstruction of structures
  • A public building of unique designs and structures with irregular arrangement or designs

Formwork Removal

When we use formworks, they are not meant to be part of the structures permanently. However, each formwork only serves a provisional purpose that when the placed concrete hardens, the formwork has to be removed. So, the formwork strength is not the most robust possible but the power needed to serve its purpose. Therefore, even from the stage of erecting the formwork, the factor of removing the formwork or formwork stripping should remain in mind.

The stage of formwork stripping also can be difficult, except certain factors are borne in mind. For instance, it can be challenging to remove the formwork parts and not cause any damage to the actual structure. Below are the essential factors that can make the removal much easier when it is time.

  • Do not hit too many nails into the formwork at the time of erecting it
  • In terms of the components of the formwork, avoid using excess. For instance, use only the right amount of timber, tie wires, braces, and other related ones
  • Arrange all the components to which they need to be removed when it is time. For instance, which panel, board, or squared timber needs to be removed first before others? Then, try to fix these components in the same order that makes the removal process as easy as it can be.

The Effectiveness of Formwork

While erecting formwork in the structure in the exact strength it should have, we also consider the aspects of the economical use of the material. This essence is of importance to enhance the formwork stripping when the time is due. It also has to consider the extensive specialized knowledge of the direction the forces will be applied to pour the concrete mix. A poorly made formwork can lead to breakage of the placed concrete inside it.

In some worst cases, the formwork can completely give way, which will result in heavy material damage and waste of other resources. It may even lead to serious injury to persons nearby. Therefore, it is crucial to consider the strength and effectiveness of formwork on-site and not overlook any condition, property or defect. At the same time, a robust formwork may also take some amount of physical effort from the person meant to remove them. And when the removal causes some difficulty, the person would resolve to spoil the formwork parts. 

Loading Requirements of Formwork

  1. Loading vertical formwork

A vertical formwork is used for making concrete walls, strip foundations and columns. And after the formwork placement, there should be an immediate adjustment until a perfect state of stability is achieved. At the same time, the concrete mix, effects of a load of its weight, development of compaction by vibration all exert lateral pressure on the formwork. This lateral pressure is often referred to as the lateral pressure of the concrete mix. And it depends on the following essential factors.

  • The technology of placing the concrete in the structure, such as concreting speed, vibration depth, the total height of the concrete mix and the compaction 
  • Properties and composition of the concrete mix in the structure. It may include the type of cement, density and quality of concrete
  • Ambient conditions such as air humidity and temperature

To lift off the lateral pressure of the concrete mix on the structure, tie rods or wires should be used, which should be included in the formwork project as a whole. However, the optimum lateral load with its external vibration can occur at the foot of the formwork. Meanwhile, it also comes with an internal beat above this foot. 

Another important factor in addition to the lateral pressure of the concrete mix is the production of buoyant forces that may also contribute to the lifting process of the formwork. This case is also handy for construction foundation formwork. And to avoid such occurrences, then the formwork needs extra anchors in the subsoil. Alternatively, you can also load the formwork with some other concrete parts.

  1. Loading horizontal formwork

Horizontal formwork is vital in the construction of ceilings, roofs and associated beams. This formwork is often subjected to vertical loads that can easily be carried off to solid subsoils. This carriage is possible only through the installation of formwork bearers or primary bearers and columns. To achieve attachment of vertical loads, they are produced by the following items.

  • Addition of reinforcements
  • A concrete mix weight in a specified height
  • Concrete cones at the spot where the concrete is poured
  • The impact of concrete pouring on the formwork
  • Working tools and persons
  • A dead load of the formwork

Apart from the vertical loads, the horizontal loads are often produced by the following

  • Wind effects
  • The inclined position of columns
  • Backing up the structure externally

You can also take up the auxiliary structure like the struts and braces in rigid connection to the other structural components like the walls and columns. Also, endeavor to back up the formwork walls and columns from all sides. You can also read about the best kitchen tapware services in Australia you can click here.

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