B 28
[Subsidiary]
L.N. 294/76.
L.N. 294/76.
L.N. 294/76.
CAP. 123]
Building Construction) Regulations
[1985 Ed.
width of that foundation, the allowable bearing pressure shall not exceed the submerged bearing capacity or such lesser value as may be required under paragraph (1);
(b) where the foundation is less than 1 metre in width, the allowable bearing pressure shall not exceed the safe bearing capacity multiplied by the actual width of the foundation measured as a decimal fraction of a metre or such lesser value as may be required under paragraph (1);
(c) the allowable bearing pressure may be increased by 5 per cent for each 0.3 m of depth below the lowest ground surface adjacent to the foundation:
Provided that it shall not exceed 2 times the safe bearing capacity specified in Table IX or such lesser value as may be required under paragraph (1).
(6) The allowable bearing pressure used in the design of foundations for resisting the combined effect of dead and imposed loads may be increased by not more than 25 per cent where such increase is solely due to wind loads.
1
TABLE IX
Safe bearing capacities of ground under foundations
Type of ground Safe bearing capacity kPa 1 Rock (granite and volcanics)––– (a) massive crystalline rock in hard sound condition (core recovery greater than 85%) 5,000 (b) medium hard rock (core recovery greater than 50%) 3,000 (c) soft rock (core recovery of 50% and less) 1,000 (d) closely jointed and heavily shattered rock To be assessed after inspection and testing. Cohesive soils (for individual footings only)-- (a) stiff clay (cannot be moulded in the fingers) 250 (b) medium clay (can be moulded by strong pressure in the fingers). 150 (c) soft clay (easily moulded in the fingers by firm pressure) 50 3 Intermediate soils (decomposed granite and decomposed volcanics)- (a) compact 300 (b) loose (dry) 200 (c) loose (wet) 100 Dry Submerged L.N. 95/78. Non-cohesive soils-- (a) compact gravel and sand-gravel mixtures 400 (b) loose gravel and sand-gravel mixtures and compact coarse sand 200 300 150 (c) loose coarse sand and compact fine sand 200 (d) loose fine sand 100 100 50