9.15.4. Foundation Walls

 9.15.4. Foundation Walls

Foundation walls are intended to support the loads transferred to them from the building #superstructure, and to safely resist any lateral soil and water pressures acting against them (Figure 9.15.-10). Where #hydrostatic pressure is present, the #foundation wall must be designed according to NBC Part 4.

Reasonably thick #cast-in-place concrete, #masonry foundation walls, and flat #ICF foundation walls are able to withstand the vertical loads from the superstructure of most Part 9 buildings with strength to spare. Both concrete and masonry, however, are relatively weak in tension. They are therefore reinforced with steel if the tensile forces become too great. Since foundation walls for residential and other small buildings are most often unreinforced, the most critical loads they are subjected to are the horizontal loads due to earth pressure.

If #basement walls are supported at the top, tension stresses are created as the walls deflect inward. If the walls are #unsupported at the top, they act as retaining walls, stabilized by the weight of the wall and the vertical superstructure loads. The greater the depth of #backfill, the stronger the foundation wall must be to resist the horizontal forces.

Quoted from Illustrated Users' Guide - NBC2015

#earthpressure #retainingwall #castinplaceconcrete #foundationwalls