What is a push-pull prop?
A push-pull prop, also called a raking prop or alignment prop (Dutch: schoorstempel), is an inclined prop used, for example, to hold vertical formwork plumb. A steel push-pull prop resembles an ordinary adjustable floor prop, but is set at an angle between the element being supported and the floor or ground. A timber version is simply called a raking shore or brace.
A steel push-pull prop usually consists of an inner and outer tube with a threaded section, allowing the length to be adjusted precisely. Each end has a hinged base or head plate for fixing. Turning the prop longer or shorter brings the element exactly plumb. Because it can both push and pull, it is known as a push-pull prop.
Application
Push-pull props are used for:
- aligning and supporting wall formwork during concreting;
- temporarily holding precast concrete walls, columns and facade panels until they are permanently connected;
- plumbing door and window frames, steel columns and timber-frame walls;
- temporarily supporting masonry or facades during alterations (with a design check).
Safety tips:
- Follow the method statement: the supplier or erection plan specifies how many props are needed, at what angle and how they are fixed. Wind on a large wall panel produces substantial forces.
- Fix securely: anchor the base and head plates with suitable anchors or bolts into a sound substrate. A loose prop can slide away.
- Check the thread: make sure enough thread is engaged in the tube and that all pins and locking devices are fitted.
- Remove only when authorised: only remove props once the wall is permanently connected and the site manager or engineer gives approval.
- Protect from impact: mark props on site; a prop struck by a vehicle can bring down a wall.
- Check after storms: inspect all props and connections after strong winds.
Related Terms
- Propping
- Formwork
- Precast concrete
- Brace
- Braced and unbraced
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