In most cases, a bearing plate is a specially-designed metal plate used to spread the force of a load-bearing wall or column out over a larger area. It may also refer to a plate used to cover, conceal or protect a bearing system inside a piece of machinery, but this definition is much less common. A bearing plate is a generally placed under a load-bearing structure, although other configurations are also available. These plates typically have additional screw or bolt holes to provide additional options when securing the load-bearing structure.
A load-bearing structure holds the weight of the building above it. Not every part of a building holds weight. In a standard house, most of the weight is on one or two internal structures as well as the four outer corners; very large or very small houses may have more or less, but five to six total load points is very common. In order to preserve the life of these structures and keep the building from settling or sagging, bearing plates are put under them to redistribute the weight.
A basic bearing plate is a metal plate that is typically less than an inch (3 cm) thick, but is quite wide and long. The actual size of the plate depends mostly on what sort of structure it is designed to fit under. In any case, the actual plate is much larger in area that the object that sits on top of it.
Load-bearing plates are generally used under walls and columns during the construction of a building. This style of plate needs a larger surface area as the building grows in height. Plates near the bottom of the building are larger than plates near the top. This helps distribute the weight of the structure more evenly, keeping the building stable.
It is not uncommon for a bearing plate to have additional features to improve its usefulness. Most plates have a wide selection of holes and fastening points to help ensure that the load-bearing structure is well-secured and the plate is properly connected to a surface. This is especially common with a bearing bracket. These brackets connect to a load surface and a surface at an angle, transferring vertical force to horizontal, or vice versa.
A common modification of a standard bearing plate is the slide-bearing plate. These are connected to a surface, but not to an above structure. These plates have a slick top surface that allows the object sitting on them to move as it expands and contracts. It both redistributes the weight and prevents damage to the system through high friction.