How many racks are needed for horizontal formwork?

Horizontal formwork is needed to create floors/ceilings in a building. To do such complex work, special floor formwork is used:

• Racks,
• Tripods,
• Crowns,
• Uniforks,
• Beams,
• Shields.

How to calculate the number of formwork posts?

The formwork post is an important element that supports the reinforced concrete floor-ceiling until it hardens. The formwork post is used together with a head (crown or unifork) and a tripod. The upper part is shaped and sized to match the thickness of the beams, and the tripod is designed to hold the formwork post in balance.

Builders use a general rule - install formwork posts every 1.5 m2. The distance between the formwork posts depends on how the beams are laid.

Wooden T-beams are laid in the transverse and longitudinal direction, i.e. there will be two layers of beams. The lower layer of beams is laid in increments of 1.5 - 2.5 m. The upper beams are placed at a distance of approximately 0.5 m. Shields are laid on the upper beams that will hold the concrete.

Therefore, the distance between the formwork posts is, on the one hand, the distance between the beams. Along the length of the beams themselves, racks should be placed every 1.5 m.

Also keep in mind that the thicker the floor, the more formwork posts you must use.

Vertical supports should be evenly spaced. Each rack can support a load of 2 tons. The total load capacity of the racks must be greater than the weight they support (the weight of beams, panels and reinforced concrete).

The formwork posts are height adjustable. But you must understand that the higher the stand is extended, the less the load on it should be.

Each vertical formwork post is equipped with a head:

• Crown, if the rack stands at the junction of the beams,
• With a unifork, if the stand is placed in the middle of the beam.

The number of heads should be similar to the number of formwork posts.

A tripod is used to support the support. Some builders save money and place tripods less often than formwork posts. The maximum you can save is to arrange the tripods through one rack. In this case, the number of tripods will be half as large as the number of racks. The tripod holds the stand in a vertical position, which is important for creating an even floor. Each stand must be in a strictly vertical position. Even a slight tilt can affect the load-bearing capacity of the rack. Therefore, to ensure the verticality of the supports, it is recommended to strengthen each of them with a tripod.

The height of the VIRASTAR formwork posts is from 2 to 5 m. The posts are telescopic, they can be extended higher or lower, fixing the selected position with a steel lock. Racks are selected according to the height of the room.

Both regular and reinforced racks are available. The outer diameter of the supports is 60 mm, the inner part is 48 mm. The steel thickness of the standard VIRASTAR formwork post is 3 mm.

You can call us or order a call from us so that we can help you calculate the formwork.

You may also be interested in the article from the Blog “How to properly install floor formwork?”