NOTE
When blocks with horizontal cores are used (see Figure 7-4), services can be accommodated inside
the block; in such cases the extra slab thickness is not required.
7.1.3.2.5
Reinforcement
7.1.3.2.5.1
The main reinforcement will be included in the fabricated joist supplied by the
manufacturer; this will be based on the slab drawings and live load required to be supported.
7.1.3.2.5.2
Additional joist reinforcement is required as follows:
(a)
joist on edge - must be able to absorb a negative moment of 20% of the free span moment: a min
of 10 mm HT bar x 1.2 m is required; and
(b)
joist in continuity over internal wall (to prevent cracks on top of the slab) - must be able to absorb
a negative moment of 60% of the free span moment: a min of 12 mm HT bar x 2.0 m is required.
7.1.3.2.5.3
The topping shall receive the fabric reinforcement installed across the joist.
7.1.3.2.5.4
When the slab span is more than 3.6 m, a central stiffener made of solid concrete or
of 80 mm blocks topped with concrete is required. The reinforcement is done with two 10 mm bars in
continuity.
7.1.3.2.5.5
The perimeter beam shall be reinforced with four 12 mm diameter bars.
7.1.3.2.6
Slab openings
(a)
small openings (less than 1.1 m across the joist) - this type of opening is contained inside two
joists and a small integrated beam shall be made and connected at each end to a minimum of two
joists; only one joist is cut. See Figure 7 -5
; and
(b)
large openings (more than 1.1 m wide) - in this case several joists are cut and a complete
reinforced concrete solution must be adopted; see Figure 7-6
.

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PCTTS 599: 20XX
126
Figure 7-5 Joist and block slab with small opening
Figure 7-6
Joist and block slab with large opening

PCTTS 599: 20XX
127
7.1.3.2.7
Balconies
7.1.3.2.7.1
Where a balcony is a cantilevered slab, the top reinforcement must be anchored in the
main floor slab for a minimum distance of 0.8 times the balcony span. In this area, at least 50 % of the
slab thickness must be of solid concrete. This additional concrete will allow for the anchorage of the
top reinforcement of the balcony slab whether the balcony span is in the same direction of the joists or
perpendicular to the joists. Figure 7-7
shows section details of a balcony.
7.1.3.2.7.2
The minimum thickness of the balcony slab shall be as follows:
The total thickness = utile thickness + reinforcement coverage (see Table 4 -7)
Where the utile thickness = 1/10 of span (minimum).
7.1.3.2.7.3
The reinforcement for balconies shall be in accordance with Table 7-2
.
Figure 7-7 Balcony section details

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PCTTS 599: 20XX
128
Table 7-2 - Balcony reinforcement using high tensile steel
Max span
m
Top reinforcement
Long. Reinforcement
Min. total
thickness
mm
Bar dia.
mm
Min. length
m
No of bars
per metre
Bar dia.
mm
No of bars
per metre
1.00
125
10
2.00
7
10
6
1.20
145
10
2.50
9
10
6
1.50
175
12
3.00
9
10
6
NOTE
When a heavy concrete staircase is connected and supported by the balcony, the above table does not
apply.
In such cases, the input of a design professional is required.


- Fall '19