Cribbing is a temporary support system used to hold loads and keep them from moving during construction. It can be made of a variety of materials including wood, plastic and steel.
A cribbing box is a type of horizontal cribbing that consists of interlocking cribs stacked one on top of another. They are ideal for supporting heavy loads and can be filled with sand, gravel or concrete to increase their stability and weight.
Using wood-crib supports to secure a load following a building collapse, vehicular accident or other event where the regular stability of the structure or vehicle has been reduced is a common use of this work. It can be much safer than jack stands and also help to prevent sliding or slipping by grabbing the metal parts of the load and keeping them from moving.
Wood is the most commonly used material for cribbing construction. It is strong enough to hold a heavy load and does not rot or deteriorate over time.
When choosing wood species for a cribbing construction, it is important to consider the compressive strength perpendicular to the grain and the hardness of the wood. Species that have a lower compressive strength perpendicular to the wood grain can be more susceptible to buckling and may need to be derated in the model.
The performance of cribs is based on several parameters that can be controlled, such as the length and width of the timbers, and the interlayer contact area. When the length of the timbers is smaller than the cross section width, the capacity and stiffness are decreased by reducing the contact area and thereby the moment of inertia.