1964_BUILDING_(CONSTRUCTION)_REGULATIONS — Page 103

1985 Ed.]

Building (Construction) Regulations

[CAP. 123

B 103

[Subsidiary]

(b) for negative moments, along lines joining the centres of the columns and around the perimeter of the column heads.

(7) The total bending moment in each direction for a panel shall be:

M1 = β2 [21 - 2D]2 WL2/10

and shall be distributed between the column strips and middle strip by the percentage specified in Table XXXVIII.

TABLE XXXVIII

Distribution of bending moments in panels of flat slabs designed by the empirical method

(a) Interior panels-

(i) with drops-

negative moments positive moments

(ii) without drops-

negative moments

positive moments

(b) Exterior panels

(i) with drops-

Distribution of moments expressed as a percentage of M1.

Column strip Middle strip

exterior negative moments SA 50 15

positive moments 20 15

interior negative moments #A 46 16

SMA 45 25

50 383

10 20

15

(ii) without drops-

exterior negative moments 41

positive moments 28 20

interior negative moments 46 =83

10 16

(8) (a) Slabs shall be reinforced in 2 directions and the reinforcement shall be so disposed that each strip is reinforced over its full width.

(b) In each strip not less than 50 per cent of the positive reinforcement shall extend in the lower part of the slab to not less than 0.125L from the line joining the centres of the columns.