CEE502
Homework8
1) A concrete beam having a width of 12 inches and a total depth of 24 inches is continuous over
two 48-ft spans with hinge or roller supports at three points. It is post-tensioned with tendons
providing effective prestress P.after losses of 230,000 lbs. The tendon profile in each span is
parabolic, with Oeccentricity at the exterior supports, -8 inch eccentricity at the interior support
and+ 8 inch eccentricity at the center of each span.
Using the method of equivalent loads:
a) Find the primary moments resulting from prestressing
b) Find the support reactions and secondary moments resulting from prestressing
c) Draw the combined moment diagram resulting from prestressing and locate the
pressure line along the span
Find the distributions of concrete flexural stress at midspan and at the interior support resulting
from:
d) Effective prestress plus total dead load of 500 plf.
e) Effective prestress plus total dead load plus a superimposed live load of 300 plf.
2) Solve Problem 1 using the method of superposition (compatible deformation).
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