1985 Ed.]
Building (Construction) Regulations
|CAP. 123
(2) The maximum stress specified in regulation 120(5) may be increased from 185 to 230 MPa.
(3) In slender beams to which regulation 116(2) applies the stress in any compression steel shall not exceed the permissible stress specified in Table XLI for compression in main reinforcement multiplied by the appropriate coefficient specified in Table XXVIII.
(4) For the purposes of this regulation the modular ratio shall be taken as 15.
159. The provisions of regulation 118 shall apply to columns of special and designed mixes subject to the maximum permissible stresses specified in Table XXXIX.
160. (1) It shall be assumed for all normal cases that the stiffness of members will be satisfactory:
Provided that--
(a) where either the stress in the reinforcement exceeds 140 MPa or the stress in the concrete exceeds 10 MPa the ratio of span to overall depth does not exceed 90 per cent of the value given in Table XXXII;
(b) where both the stress in the reinforcement exceeds 140 MPa and the stress in the concrete exceeds 10 MPa the ratio of span to overall depth does not exceed 85 per cent of the values given in Table XXXII.
(2) In the case of members designed by the load factor method, the limiting stresses for the purposes of paragraph (1)(a) and (b) shall be the stresses at working loads.
161. (1) Subject to the following provisions of this regulation, reinforced concrete members may be designed to have a load factor of not less than 1.8 against crushing of the concrete and against yielding of the steel.
(2) For the purposes of paragraph (1) the resistance to crushing of the concrete in the member shall, for beams and slabs, be assumed to be-
(a) not more than of the specified resistance to crushing of the concrete for the works test at 28 days-
(i) for ordinary concretes in accordance with Table IV; (ii) for Quality A concretes in accordance with Table V; and
(iii) for special concrete mixes in accordance with Table VI; and
(b) not more than of the specified resistance to crushing of the concrete for the works test at 28 days for designed concrete mixes in accordance with Table VI.
B 107
[Subsidiary]
L.N. 294/76.
Stresses in columns of special and designed mixes.
Stiffness of members with higher steel and concrete stresses. L.N. 294/76.
Load factor method of design.