9.4.4.

(1) Footing sizes for shallow foundations shall be,

(a) determined in accordance with Section 9.15., or

(b) designed in accordance with Section 4.2. using,

(i) the maximum allowable bearing pressures in Table 9.4.4.1., or

(ii) allowable bearing pressures determined from subsurface investigation.

(2) The design procedures described in Section 4.2. are permitted to be used in lieu of the design procedures in this Subsection.

(3) The design procedures described in Section 4.2. shall be used where,

(a) deep foundations are used,

(b) the footing size falls outside the scope of this Section, or

(c) the foundation is constructed on peat, filled ground or on sensitive clays as described in Article 9.15.1.1.v1v2

(1) Where a soil or rock within a distance equal to twice the footing width below the bearing surface has a lower allowable bearing pressure than that at the bearing surface as shown in Article 9.4.4.1., the design capacity of the foundation shall not be greater than would cause the weakest soil or rock to be stressed beyond its allowable bearing pressure.

(2) In calculating subsurface pressures referred to in Sentence (1), the loads from the footings shall be assumed to be distributed uniformly over a horizontal plane within a frustum extending downward from the footing at an angle of 60° to the horizontal.

(1) Where a foundation bears on gravel, sand or silt, and the water table is within a distance below the bearing surface equal to the width of the foundation, the allowable bearing pressure shall be 50% of that determined in Article 9.4.4.1.

(1) Where a foundation is located in an area where soil movement caused by changes in soil moisture content, freezing, or chemical-microbiological oxidation is known to occur to the extent that it will damage a building, measures shall be taken to preclude such movement or to reduce the effects on the building so that the building’s stability and the performance of assemblies will not be adversely affected.

(2) Any surcharge shall be in addition to the equivalent fluid pressure specified in Sentence (1).

(1) Except where constructed in accordance with Section 9.15., walls supporting drained earth shall be designed,

(a) for a pressure equivalent to that exerted by a fluid with a density of not less than 480 kg/m³ and a depth equal to that of the retained earth, or

(b) in accordance with Section 4.2. so as to be able to resist the loads and effects described in Article 4.1.2.1.

(2) Walls supporting other than drained earth shall be designed,

(a) for the pressure described in Clause 1(a) plus the fluid pressure of the surcharge, or

(b) in accordance with Section 4.2. so as to be able to resist the loads, forces and effects described in Article 4.1.2.1.