1985 Ed.]
Building (Construction) Regulations
[CAP. 123
B 77
(Subsidiary]
Provided that-
(a) the magnitude of the shear stress so calculated shall not exceed 4 times the maximum permissible shear stress for the concrete alone; and
(b) the local bond stress in the main reinforcement calculated in accordance with regulation 141(2)(a) does not exceed the maximum permissible local bond stress specified in regulation 116.
(2) Tensile reinforcement which is inclined and carried through a depth of beam equal to the arm of the resistance moment may also act as shear reinforcement provided it is anchored sufficiently.
126. (1) A stirrup in reinforced concrete shall pass round, or otherwise be adequately secured to, the appropriate tensile reinforcement and each end of that stirrup shall be properly anchored.
(2) Where at any cross-section the shear stress, as calculated from the equation given in regulation 140(1) does not exceed the permissible shear stress for the concrete, nominal stirrups shall be provided at a spacing not exceeding the arm of the resistance moment, or 450 mm, whichever is the smaller. Such nominal stirrups shall be not less than 6 mm in diameter for beams not more than 450 mm in depth and not less than 10 mm in diameter for beams more than 450 mm in depth:
Provided that in any event the cross-sectional area of such stirrups shall be not less than 0.15 per cent of the horizontal cross-sectional area of the beam.
127. In a reinforced concrete solid slab spanning in one direction-
(a) distributing reinforcement shall be provided at right-angles to the main tensile reinforcement of that slab; and
(b) the area of reinforcement in each direction shall be not less than 0.15 per cent of the gross cross-sectional area of the concrete at right-angles to the direction of the reinforcement.
128. (1) Where compression reinforcement is required in a beam, it shall be effectively anchored against buckling by stirrups at points not further apart, measured from centre to centre, than 12 times the diameter of that compression reinforcement or 300 mm, whichever is the smaller.
(2) Where the area of the compression reinforcement in a beam exceeds 4 per cent of the cross-sectional area of the beam, any steel in excess of that percentage shall be ignored in calculating the resistance moment of the beam.
Stirrups.
L.X. 394/76.
Reinforcement in solid slabs.
Compression reinforcement. L.X. 394/76.