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)

= 1255 mm 2 Bottom 3T25 (1473 mm 2 )
438 Practical design and detailing
_ M _ (203)(10 6 ) _
K- fcubd 2 - (40)(350)(5002) - 0·058
< 0.156
From Table 4.7-2 (or eqns 4.7-6 and 4.6-3),
Z
d=0.93
From eqn (4.7-9),
X
d=0.16
_ M _ (203)(10 6 )
As - 0.87/yz - (0.87)(460)(0.93)(500)
= 1091 mm 2 3T25 U-bars (1473 mm 2 )
From Table 4.10-2,
ultimate anchorage bond length = 324J = 800 mm
Using eqns (6.6-3(a), (b)),
required anchorage length = u~~~ ]<800)
= 593 mm
Span BC (Fig. 11.5-9(d)). From Section 4.8,
effective flange width = 350 + (0.2)(0.7 of 7000)
= 1330 mm
From bending moment envelope (Fig. 11.5-6),
M = 236 kNm
M (236)(10 6 )
fcubd 2 = (40)(1330)(500Z) = 0·018
From Table 4.7-2,
< K' of Table 4.7-1
~ = 0.94 j = 0.13 (i.e. 0.9x < hr)
From eqn (4.8-3),
M (236)(10 6 )
As = 0.87/yz = (0.87)(460)(0.94)(500)
End support C (Fig. 11.5-9 (e)). Design for 40% of the initial fixed-end
moment-see Comments on Step 5 at the end.