B 66
[Subsidiary]
Joints in columns.
L.N. 294/76.
Filler floor beams. L.N. 294/76.
CAP. 123] Building (Construction) Regulations
[1985 Ed.
(b) For solid round steel columns in cases where the loading on the cap or under the base is uniformly distributed over the whole area including the column shaft, the minimum thickness, in mm, of a square cap or base shall be:
9W
X
D
16p D-d
where t is the thickness of the plate in mm;
W is the total axial load in kN;
p is the permissible flexural stress in extreme fibres of slab bases in MPa;
D is the length of the side of cap or base in mm;
and
d is the diameter, in mm, of the column or, where the column has a reduced end, of the reduced end.
(c) For other cases calculations shall be made, based on the allowable stress of 185 MPa.
105. (1) All column joints shall be designed and constructed to transmit safely all the forces to which they are subjected.
(2) (a) Column joints in which the resultant unit stress is wholly compressive and which depend on contact for the transmission of load shall be sufficiently spliced to retain the members in place.
(b) Each splice plate shall extend above the joint to a distance at least equal to the maximum breadth of the column flange or 150 mm, whichever is the greater dimension, and shall extend below the joint to a similar distance.
(c) Where the whole of the end of a superimposed column is not in effective contact with the column beneath, a seating plate of adequate thickness, which shall extend the full depth and width of the lower column, shall be interposed between the ends of the columns.
106. (1) The strength of filler floor beams solidly encased in a concrete floor slab shall be calculated by either of the following methods--
(a) on the basis of the combined moment of inertia of the steel and the surrounding concrete (calculated as in reinforced concrete neglecting the strength of concrete in tension), in which case the flexural stress in extreme fibres shall not exceed 150 MPa.
(b) on the basis of the section modulus of the fillers alone, in which case the flexural stress on extreme fibres may be taken as (160+0.67fcu) MPa, where fcu is the number of mm,