Civil Engineering Reference
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Bridge construction. (PhotoDisc, Inc./Getty Images.)
applied to the beam. These deflections can be computed and superimposed on the ones
caused by the tendons. Figure 19.11(d) shows the
L
deflection of a uniformly loaded
simple beam obtained by taking moments at the
L
when the conjugate beam is loaded
with the
M
/
EI
diagram.
Example 19.4 shows the initial and long-term deflection calculations for a rectangular
pretensioned beam.
EXAMPLE 19.4
The pretensioned rectangular beam shown in Figure 19.12 has straight cables with initial stresses of
175 ksi and final stresses after losses of 140 ksi. Determine the deflection at the beam
L
immedi-
ately after the cables are cut.
E
4
10
6
psi. Assume concrete is uncracked.
Figure 19.12
