Allowable capacity for bearing, bond or friction of ground
(1) The allowable capacity for bearing, bond or friction of the ground supporting any foundation under working load shall not exceed-
(a) the ultimate capacity for bearing, bond or friction of that ground with an adequate factor of safety against failure; or
(b) the value in relation to bearing, bond or friction of that ground such that the deformation or movement (including total settlement, differential settlement and lateral movement) will not be greater than that which can be tolerated by the building, building works, structure or street supported by the foundation,
whichever is the less.
(2) The ultimate capacity for bearing, bond or friction of the supporting ground shall be determined by-
(a) suitable tests to establish the engineering properties of the supporting ground together with the application of recognized foundation engineering principles; or
(b) testing of the foundation on site; or
(c) other suitable methods.
(3) Where the allowable bearing capacity is to be determined on the basis of the ultimate bearing capacity of the supporting ground, due consideration shall be given to all the circumstances, including the ground water conditions, the shape and depth of the foundation, the inclination and eccentricity of the loads, and the nature and slope of the surrounding ground, and, in the case of rock, the presence of dissolution features, the jointing of the rock and the spacing, dip, thickness and degree of weathering of the joints and any other relevant characteristics.
(4) The allowable capacity of foundations for bearing, bond or friction resisting the combined effects of dead, imposed and wind loads may be increased by not more than 25% where such increase is solely due to wind loads.