15 Feb What Is An Acrow Prop?
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.
The safe working load (SWL) that each Acrow Prop can bear depends on the size (please see table). The SWL decreases as the prop is extended.
Acrow Prop Uses
Acrow props are used mainly for shoring to provide temporary support during building repair or alteration work. 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 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.
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 = 101.98 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.