An Acrow prop is a telescopic tubular steel piece of construction equipment. It is used as a temporary support. Acrow props are known by several names including shore prop, acro prop, acro jack and post shores. They are height adjustable by a wide diameter screw thread which is on the outside of the tube. The use of a screw thread means that the props are able to be tightened when already in place, which allows the user to adjust the load that each one bears (adjustable load bearing).
The safe working load (SWL) that each Acrow Prop can bear depends on the size (please see above table). The SWL decreases as the prop is extended.
Uses
Acrow props are used mainly for shoring to provide temporary support during building repair or alteration work for overhead structures during construction. A typical use is to support an existing vertical beam whilst supports are removed or restored. Strongboys are used when masonry itself is to be supported; the strongboy is positioned into the bed joints. Then, an Acrow prop is put in place. Existing windows or doorways may also be supported directly or using strongboys. The base and top plates of Acrow props have a 150mm x 150mm surface area, so they are great for supporting a vertical load but are at risk of toppling if there is any sideways force. If this is a possibility, props should be strutted or braced with scaffolding tubes.

Although the original Acrow prop was only envisioned for vertical support, the range has since been expanded. Shoring 'push and pull' props with swivelling footplates are used to support concrete formwork. Trench struts are used for shoring horizontal trench work. These are similar, but have a 'claw' form to their baseplates.

General information

If you divide the weight to be held by the kN capacity of the prop this will tell you how many props you need. Adding bracing to a propping system will increase the capacity the propping can hold. 1 kN = 101.971621298 kilograms - force. Always seek the advice of a professional before undertaking any propping / shoring projects. A propping job that goes wrong can be disastrous, endanger lives and be extremely expensive to fix.

Australian Scaffold provides a propping service using our telescopic / acrow props or for heavier loads we use the Layher Allround scaffold which makes an ideal propping system:
» being both a scaffolding and a propping system it is economic and versatile
» it has extremely high strength capacity values, is self supporting and is quick to install

Allround in standard configurations up to six metres is rated for the following permissible loadings:
» with lifts of 2.0 metres - up to 45 kN per standard
» with lifts of 1.5 metres - up to 60 kN per standard
» with lifts of 1.0 metres - up to 70 kN per standard

Permissible loadings can be increased considerably further by:
» using Layher's reinforced base jacks and U head jacks
» additional bracing (ledgers and diagonals), and / or
» joining standards with our unique twin wedge couplers

For example, a single six metre Allround tower can support loads of close to 700kN or even higher!
In applications where the load-bearing capacities of traditional falsework towers are exceeded, it is possible to use the heavy duty towers and columns using Allround scaffolding. Heavy duty spindles fit into specially designed heavy-duty top and bottom collars. This grouping of the standards allows a large increase in the capacity over individual standards. An extremely high load-bearing capacity is achieved by combining four Allround standards. This support can be used in a number of arrangements with various load-bearing capacities: a heavy duty tower or a heavy duty column. These arrangements can be further expanded by using Layher Allround standard components to cater for a vast variety of irregularly shaped areas.

Appropriate static calculations should be performed to prove the appropriate configuration of Allround components for each individual situation.

Refer to AS 3610 for acceptable criteria in installation of props and eccentricity of loading.