1985 Ed.]
Building (Construction) Regulations
[CAP. 123
B 75
[Subsidiary]
(4) At each lap in each longitudinal reinforcement, the spliced reinforcements shall overlap longitudinally through a distance of not less than--
(a) (i) 24 times the diameter of the smaller reinforcement for compressive reinforcement; and
(ii) 30 times the diameter of the smaller reinforcement for tensile reinforcement; or
(b) a sufficient distance to develop the force in the reinforcement by bond, as calculated in accordance with regulation 141,
whichever is the greater dimension.
122. (1) (a) A reinforced concrete column shall have transverse or helical reinforcement so disposed as to provide all necessary restraint against the buckling of each of the longitudinal reinforcements. Every bar in a column near the face should be properly linked.
(b) The transverse or helical reinforcement shall be secured to the longitudinal reinforcements, and the ends of such transverse or helical reinforcement shall be properly anchored.
(2) The diameter of transverse reinforcement shall be not less than 6 mm or 1/4 of the diameter of the longitudinal reinforcement, whichever is the greater dimension.
(3) The pitch of the transverse reinforcement shall not exceed
(a) the least lateral dimension of the column;
(b) 12 times the diameter of the smallest longitudinal reinforcement in that column; or
(c) 300 mm,
whichever is the least dimension.
(4) (a) Helical reinforcement shall be of regular formation with the turns of the helix spaced evenly.
(b) Where an increased load on the column on account of the helical reinforcement is allowed for under regulation 143(1)(b), the pitch of the helical turns shall be--
(i) not more than 75 mm or 1/6 of the core-diameter of the column, whichever is the lesser dimension; and
(ii) not less than 25 mm or 3 times the diameter of the helical reinforcement, whichever is the greater dimension.
(c) Where an increased load on the column on account of the helical reinforcement is not allowed for, the requirements of paragraphs (2) and (3) shall be complied with.
Transverse or helical reinforcement for columns.
LN 294/76.
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