1964_BUILDING_(CONSTRUCTION)_REGULATIONS — Page 27

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1985 Ed.]

Building (Construction) Regulations

[CAP. 123

B 27

[Subsidiary]

31. (1) In the design of foundations, consideration shall be Settlement. given to-

(a) the probable differential settlement of the building; and (b) the probable total settlement of the building.

(2) Where appreciable variations in ground conditions occur on a site on which a new building or an extension to an existing building is proposed to be erected special consideration shall be given to probable differential settlement and, if the Building Authority so requires, calculations of the estimated settlements shall be provided.

300

(3) The estimated differential settlement shall in no case induce an estimated angular distortion in excess of 366 in any part of the proposed structure unless the Building Authority is satisfied that in the special circumstances of the case an estimated angular distortion in excess of 30 is acceptable.

32. (1) The safe bearing capacity of the ground shall have a factor of safety of not less than 3 on the ultimate bearing capacity.

(2) Unless adequate tests are carried out to justify higher values the safe bearing capacity adopted shall not exceed that specified in Table IX for the appropriate type of ground.

33. (1) The pressure on the ground under any foundation shall not exceed the allowable bearing pressure which shall be the safe bearing capacity or such lesser value as may be necessary for the control of settlement or for the safety of adjacent cuttings or slopes, to the satisfaction of the Building Authority.

(2) Where it is proposed to exceed the values in Table IX, the allowable bearing pressure for rock-

(a) shall be determined with due regard to all the circum-

stances, including the depth of foundations, the jointing of the rock and the spacing, dip. thickness and degree of weathering of the joints; and

(b) shall not exceed the permissible bearing pressure of the

material of the foundation.

(3) For decomposed granite and decomposed volcanics where approved tests show that the safe bearing capacity exceeds the values specified in Table IX, the allowable bearing pressure for shallow foundations shall not exceed 2 times the value specified in Table IX or such lesser value as may be required under paragraph (1).

(4) For cohesive soils where approved tests show that the safe bearing capacity exceeds the values specified in Table IX, the allowable bearing pressure shall not exceed 1 times the value specified in the Table IX or such lesser value as may be required under paragraph (1).

(5) For non-cohesive soils-

(a) whenever there is a risk of the ground water level rising to a depth below the base of the foundation of less than the

Safe bearing capacity.

Allowable bearing pressure.