F. K. Kong MA, MSc, PhD, CEng, FICE, FIStructE, R. H. Evans CBE, DSc, D ès Sc, DTech, PhD, CEng, FICE, FIMechE, FIStructE (auth.)-Reinforced and Prestressed Concrete-Springer US (1987)

430 Practical design and detailing
From eqns (6.6-3(a), (b)),
the required lap length = (321/J) [ 0.[7 1 J
From Section 4.10,
= (321/J) [As,req( = _116. 7)]
As,prov(- 196)
= 191/J = 190 mm
minimum lap length = 300 mm > 191/J
Tie lap length = 300 mm
Step 10 Reinforcement details
The reinforcement details are shown in Fig. 11.5-3, which conforms to
the Standard Method of Detailing of Structural Concrete [1), as
explained in Example 3.6-3. Thus the label104TJ0-1-150Bl tells us that
there are 104 deformed bars (/y = 460 N/mm 2 ) of size 10, that these bars
have the 'bar mark 1', and that the bar spacing is 150 mm; B 1 tells us that
these bars are at the bottom outer layer. (Similarly, 82 denotes bottom
upper layer; T1 denotes top outer layer and T2 top lower layer.) The bar
marks indicate the probable sequence of fixing; thus bars 'mark 1' are
fixed first, then 'mark 2', then 'mark 3' and so on. Note the following
comments regarding BS SilO's detailing requirements:
(a) Main bars at midspan (mark 1)
Curtailment: As explained in Section 8.8, in a continuous slab the
main tension bars at midspan should extend to within 0.21 of the
supports, and at least 40% should extend into the support.
In Fig. 11.5-3, the bars 'mark 1' are staggered, 50% being
curtailed at 925 + 175 = 1100 mm (= 0.21) from the supports.
Bar spacing: As explained in Section 8.8, the clear spacing should
not exceed 3d (462 mm) or 750 mm whichever is the less.
(b) Secondary bars (marks 2, 3, 4 and 6)
Bar spacing: As explained in Section 8.8, the clear spacing should
not exceed 3d (462 mm) or 750 mm whichever is the less.
Minimum area: All secondary bars exceed the minimum area
requirement of 0.13%bh (see Section 8.8).
Minimum lap length: As explained in Section 4.10, the minimum
lap length should not be less than 151/J or 300 mm whichever is the
less.
(c) Main bars at supports (mark 5)
Curtailment: As explained in Section 8.8, the main bars at supports
should extend a distance of at least 0.151 or 451/J, from the face of
support whichever is greater, and at least 50% should extend 0.31.
In Fig. 11.5-3, all bars 'mark 5' extend a distance of at least
850 mm from the face of the support; this exceeds 0.151 or
451/J. The bars are staggered, 50% being extended 850 + 850 =
1700 mm (>0.31) from the face of the support.
(d) Transverse reinforcement across main beam (mark 5)