Purpose of Wall Footing
Wall footing is also known as
built specifically to support walls. These building concrete footings are placed below bearing walls that are located at both interior and exterior of a structure.
For bearing walls at building’s interior, these footings can be poured monolithic with the slab as shown on detail 2. Compare that with the continuous footings at exterior such as the footing detail 1.
Though these two footing details have the capacity to carry the same amount of vertical load, the footing in detail 1 has additional purpose.
In addition to supporting bearing walls, these footings provide lateral support for the building. During high wind or earthquake events, continuous footings provide the counter balance forces necessary to stabilize structure from falling over.
The walls that are designed to resist lateral forces caused by wind and earthquakes are called shear walls. These shear walls are anchored to continuous footings with anchor bolts, as shown on top of the foundation wall per detail 1. Also common in this type of walls are straps and hold downs which are part of the lateral supports.
In any given structure about half of the building exterior walls are non-bearing that do not normally require footings. …so why are all exterior walls built on continuous footings?
As stated above due to the lateral support functions of continuous footings all houses or structures in general require wall continuous footings.
During footing design process these continuous footings are sized based on the weights they carry, the heavier the load, the wider the footings.
For walls shown on plans without thicken slab or continuous footings they are partition or divider wall sometimes called non-structural walls.
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