1985 Ed.]
Building (Construction) Regulations
[CAP. 123
B 61
[Subsidiary]
Provided that in no case shall the maximum flexural stress in extreme fibres of the cased section exceed either-
(i) 14 times the maximum permissible stress on the uncased section of that beam or girder; or
(ii) that specified in Table XXIII.
whichever is the lesser stress.
TABLE XXIII
Maximum flexural stresses in extreme fibres of the cased section of a beam or girder
1MPa 1. Steel complying with the appropriate provisions of BS 4360: 1972- (a) beams or girders other than plate/girders150 (b) plate girders145 2. High yield stress structural steel complying with the appropriate provisions of BS 4360: 1972-- (a) beams and girders, other than plate girders- (i) material not more than 25 mm thick310 (ii) material more than 25 mm thick190 (b) plate girders- (i) material not more than 25 mm thick200 (ii) material more than 25 mm thick185L.N. 394/76.
98. (1) The permissible ratio of effective column or strut length (l) to least radius of gyration (k) shall not exceed the following values:
(a) for any member carrying loads resulting from dead and imposed loads
Stresses in columns and struts.
180
(b) for any member carrying loads resulting from wind forces only, provided the deformation of such member does not adversely affect the stress in any part of the structure carrying loads resulting from dead and imposed loads...
250
(c) for any member normally acting as a tie in a roof truss but subject to possible reversal of stress due to the action of wind suction
350
(2) Subject to the provisions of paragraph (3) and of regulations 99 and 100 the axial stress on column and struts of steel shall not exceed the maximum permissible axial stress specified in Table XXIV for the ratio l/k specified in that Table.