B 108
[Subsidiary]
Slender beams and long columns designed by the load factor method.
Simplified formulae for rectangular beam and solid slab sections in load factor method.
CAP. 123] Building (Construction) Regulations [1985 Ed.
(3) For the purposes of paragraph (1) the resistance to crushing of the concrete in the member shall, for columns, be assumed to be—
(a) not more than 0.68 times 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 0.76 times the specified resistance to crushing of the concrete for the works test at 28 days for designed concrete mixes in accordance with Table VI.
(4) For the purposes of paragraph (1)—
(a) the maximum stress in the concrete at failure shall be taken as not more than of its resistance to crushing as assumed in paragraph (2) or (3) and considered as constant over the depth of the compression zone, which depth in the case of beams and slabs shall not be taken as greater than effective depth of the member;
(b) the yield point of the reinforcement shall be taken as not greater than 1.8 times the appropriate maximum permissible stress specified in Table XXIX and regulation 158.
(5) Paragraph (1) shall apply only where the stresses in the members at working loads are not such as to cause excessive cracking or excessive deflexions.
162. (1) For a beam to which regulation 116(2) applies designed by the load factor method, the maximum permissible load shall be the maximum load calculated as for a normal beam and multiplied by the coefficient specified in Table XXVIII for the appropriate slenderness ratio.
(2) For a column to which regulation 118(2) applies designed by the load factor method, the maximum permissible load, or combination of direct load and bending moment, shall not exceed the maximum load, or combination of direct load and bending moment calculated as for a short column and multiplied by the coefficient specified in Table XXX for the appropriate ratio of effective column length to least lateral dimension.
163. For beams and solid slabs of rectangular cross-section without compressive reinforcement and for qualities of concrete and steel within the range permitted by these regulations, the requirements of regulation 161 may be deemed to be satisfied if the resistance moment (Mr) (corresponding to the working loads) is assumed to be the lesser of the 2 values calculated from the following 2 equations:
B 108
[Subsidiary]
Slender beams and long
columns designed by the load factor method.
Simplified formulae for
rectangular beam and solid slab sections in load factor method.
CAP. 123]
Building (Construction) Regulations
[1985 Ed.
(3) For the purposes of paragraph (1) the resistance to crush- ing of the concrete in the member shall, for columns, be assumed to be-
(a) not more than 0.68 times the specified resistance to crush-
ing 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 0.76 times the specified resistance to crush- ing of the concrete for the works test at 28 days for designed concrete mixes in accordance with Table VI.
(4) For the purposes of paragraph (1)—
(a) the maximum stress in the concrete at failure shall be taken as not more than of its resistance to crushing as assumed in paragraph (2) or (3) and considered as constant over the depth of the compression zone, which depth in the case of beams and slabs shall not be taken as greater than effective depth of the member;
the
(b) the yield point of the reinforcement shall be taken as not greater/than 1.8 times the appropriate maximum permis- sible stress specified in Table XXIX and regulation 158.
(5) Paragraph (1) shall apply only where the stresses in the members at working loads are not such as to cause excessive cracking or excessive deflexions.
162. (1) For a beam to which regulation 116(2) applies designed by the load/factor method, the maximum permissible load shall be the maximum load calculated as for a normal beam and multiplied by the coefficient specified in Table XXVIII for the appropriate slenderness ratio.
(2) For a column to which regulation 118(2) applies designed by the load factor method, the maximum permissible load, or combination of direct load and bending moment, shall not exceed the maximum load, or combination of direct load and bending moment calculated as for a short column and multiplied by the coefficiebt specified in Table XXX for the appropriate ratio of effective column length to least lateral dimension.
163. For beams and solid slabs of rectangular cross-section without compressive reinforcement and for qualities of concrete and steel within the range permitted by these regulations, the require- ments of regulation 161 may be deemed to be satisfied if the resistance moment (M,) (corresponding to the working loads) is assumed to be the lesser of the 2 values calculated from the following 2 equations:
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