Acrow props

A prop is an accessory used by masons to temporarily support a building, such as a ceiling under construction. Simple, telescopic, push-pull, or heavy versions are available to meet different needs on the construction site.

Some essential information about props is important to know.

- They consist of two tubes sliding one (the inner tube) inside the other (the outer tube).

- A pin is used to lock the movements of the inner tube. This part transmits the tensile and compressive forces exerted by the weight of the supported structure.

- A sleeve connects the inner tube to the outer tube.

- Base plates or shoes located at the ends are used to attach them to the base support and to the structure to be stabilized.

- Plates placed at the ends prevent users from getting injured.

A simple prop is used during the construction of a wall or a roof. It resists compressive forces along its axis. It must have certain features to comply with the standard NF EN 1065:

- a anti-dislodgement system that prevents the inner tube from coming out of the outer tube;

- a pin of at least 13 mm in diameter that must extend beyond the body of the sleeve by at least 20 mm;

- a minimum overlap of 10 cm when the two tubes are nested;

- a coverage of the inner tube of at least 30 cm in length when the equipment is fully deployed;

- a possibility of adjustment of at least 1 m.

A push-pull prop is recommended when tensile movements are added to the compression:

- they are used when installing prefabricated elements, columns, beams, or lintels;

- the minimum load must be more than 20 kN;

- the maximum angle of inclination is 45° relative to the horizontal;

- its length can reach 10 m.

Some parameters are to be considered in the choice of equipment:

- heavy models (up to 110 kg) are preferable for supporting a large structure;

- the use of a shoring tower is recommended if the work assumes handling materials over 10 kg with a shoring height of 170 cm to 290 cm;

- the selected equipment must be suitable for the load to be supported in order to avoid any risk of collapse.

Thus, the choice of a prop depends on the shoring height, the load to be supported, but also on the nature of the structure to be supported (beams, ceiling, wall, etc.).