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)

418 Practical design and detailing
177
Fig. 11.4-7 Bending moment diagram (kNm)-Example 11.4-l(d)
storey as given in Example 11.4-1(b) is very similar, this is now left as
an ·exercise for the student. The bending moment diagram is as given in
Fig. 11.4-7.
Example 11.4-l(e)
With reference to the braced frame in Example 11.4-1(a) and Fig. 11.4-3,
explain the use of the sub-frame of Fig. 11.4-1 (h) for finding the column
moments.
SOLUTION
Note that the sub-frame of Fig. 11.4-1(h) can be used to find column
moments only. The loading applied must be that which produces the worst
out-of-balance moment at the beam-column joint, i.e. in this case BC is
to be loaded with the full design load 1.4gk + 1.6qk = 122 kN/m and
CD with the minimum design dead load l.Ogk = 36 kN/m.
Figure 11.4-8 gives the resulting bending moment diagram which
should be checked. Comparison of the column moment values obtained
with those given in Examples 11.4-1(b) and (d) shows that even this
minimum sub-frame gives a good approximation in a satisfyingly rapid
manner.
178
1045 t
+
3m
J
3m
178
• 1-
8
I.
10m
Bm
_j__
Fig. 11.4-8 Bending moment diagram (kNm)-Example 11.4-l(e)