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)

330 Reinforced concrete slabs and yield-Line analysis
of slab. The slab measures 8 by 6 m; by considering a reasonable collapse
mode, such as that shown in the figure, calculate the value of the uniformly
distributed load q that would just cause collapse. Check your answer
against the general algebraic solution of Example 8.4-2.
Ans. 13.91 kN/m 2 .
8.4* Figure (a) shows a uniform rectangular slab simply supported along
the edges BC, CD and DA and fully fixed along AB; it carries a uniformly
distributed load of intensity q. The slab is reinforced at the bottom face
with two uniform layers of reinforcement, giving a moment of resistance
M per metre width for bending about an axis parallel to AB and 0.5M per
metre width for bending about an axis parallel to AD. It is also reinforced
(a)
(b)
Problem8.4
at the top face to give a moment of resistance of 0. 15M per metre width for
hogging bending about an axis parallel to AB.
By considering the yield-line pattern in Fig. (b), estimate the collapse
value of q according to yield-line theory, if M = 40 kNm per metre width
of slab.
Ans.
24.48 kN/m 2 (y = 2.85 m; x = 2.21 m).
8.5* Figure (a) shows a slab simply supported along the edges AB, BC
and CD and unsupported along AD; it carries a uniformly distributed load
of intensity q. The slab is reinforced with two uniform layers of
• Cambridge University Engineering Tripos: Part II (past examination question).