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)

442 Practical design and detailing
actual span/depth ratio = 90001500 = 18.0
< 26.6
Step 8 Cracking
Table 11.5-3 Bar spacing and corner distance
span/depth ratio OK
Spacing ab (Fig. 5.4-1) Spacing ac (Fig. 5.4-1)
Moment
redistr. Actual Allowed Actual Allowed
Tension (Fig. (Fig (Table (Fig. (Table
bars 11.5-6) 11.5-12) 5.4-1) 11.5-12) 5.4-1)
Support B: -17% 34mm 135mm See Comments at end
top
Span AB: 0 34mm 160mm 60mm 80mm
bottom
Span BC: -19% 92mm 132mm 60mm 66mm
bottom
Crack widths OK
Step 9 Robustness (BS 8110: Clauses 3.1.4.3, 3.12.3.4, and 3.12.3.6)
Internal longitudinal ties (BS 8110:Clause 3.12.3.4.1).
F 1 = 20 + 4 times No. of storeys = 36 kN/m
From Step 2 of the solution to Example 11.5-1,
gk = 32.115.5 = 5.84 kN/m 2 of floor
qk = 16.5/5.5 = 3.00 kN/m 2 of floor
Check:
Hence
[gk7~5 qk](~)Ft
= [5.84 7~5 3.00][~](36)
= 76.4 kN/m > 36 kN/m
tie force = (76.4 kN/m)(5.5 m) = 420 kN
. . . . I . _ (420)(10 3 ) _
1049
2
mmtmum contmuous mterna tie - *(0.87)( 460) - mm
Bottom 2T32 (1608 mm 2 continuous through support B)
*rm could have been taken as 1.0. See BS 8110: Clause 3.12.3.2.