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)

(k:,~:J
100
100kN 100kN 100kN
~ ~ ~ ~
Summary of design procedure 395
0
D E F
Md
c
10oj A
(kNm) o --~~~~~~~~~~~~~---
~ 300
c 200
B 100
~e o
!'!.§ 100
~-· 200
~~ 300
0
centroidal axis
Fig.10.5-1
centroidal distance from soffit a 1 = 394 mm
(In practice, sections may be chosen from tables, such as those in
Appendix B of Reference 1.)
Step2
From eqn (10.4-10),
Use
p . = [famin(Zt + Z2) + Mr]A
cmm
z, + z2
= (0 + 266 X 10 6 ) X 160 000 = 946 kN
22x10 6 +23x10 6
Pc = 105%Pcmin(say) = 1000 kN(say)
Step3
The permissible zone for the line of pressure is given by eqns (10.4-5) to
(10.4-8). Substituting in numerical values it will be found that eqns
(10.4-5) and (10.4-8) are the two critical ones. The reader should verify
that the limiting values for eP at sections A, B, C, D, E and F are as
plotted in Fig. 10.5-1. (If in doubt see Example 9.2-4 for method of
calculation.)
Step4
Try a concordant profile; say, one following the imposed-load bending