1964_BUILDING_(CONSTRUCTION)_REGULATIONS — Page 104

B 104

[Subsidiary]

CAP. 123 Building (Construction) Regulations

[1985 Ed.

(c) Not more than 50 per cent of the positive reinforcement may be bent up at a distance of not less than 0.25L from the centre line of the panel.

(d) Not less than 50 per cent of the negative reinforcement shall extend not less than 0.3L beyond the line joining the centres of the columns.

(e) Negative reinforcement in the top of the slab shall not stop or be bent down at a distance of less than 0.2L from the line joining the centres of the columns as shown in Diagram 9.

(9) (a) Internal columns shall be designed to resist 50 per cent of the maximum negative moment in the column strip.

(b) External columns shall be designed to resist 90 per cent of the maximum negative moment in the column strip.

(c) These moments shall be apportioned between the upper and lower columns in proportion to their stiffnesses.

(d) When external columns carry portions of the floors and walls as a cantilevered load the specified column moments may be reduced by the moment due to dead load only on the cantilever.

DIAGRAM 9

Details of Reinforcement

0.3 L Min.

COLUMNS

0.3 L Min.

NOT LESS THAN 50% OF TOTAL NEGATIVE REINFORCEMENT

0.2L Min.

0.2 L Min.

BENT-UP BARS

0.25L Max.

0.125 L Max

NOT LESS THAN 50% OF TOTAL POSITIVE REINFORCEMENT

Maximum permissible stresses in special and designed mixes.

157. (1) Subject to the provisions of regulations 118 and 120 the compressive, shear and bond stresses in reinforced concrete constructed of special or designed mixes shall not exceed the maximum permissible stresses specified in Tables XXXIX and XL for the appropriate mix.