A simply supported rectangular beam is uniformly loaded and is prestressed the tendons provided for prestressing should be
Answers
Answer:
SOLUTION
As per the load balancing concept in pre-stresses concrete beam, the profile of tendon must be the same as that of the bending moment diagram (BMD) of beam due to external load only.
For ex, if a simply supported beam is subjected to a concentrated load at mid span, then BMD of that beam will be triangular with maximum BM at mid span and hence, shape of cable will be ‘V’ shape or triangular with maximum eccentricity at mid span (See figure I).
∴ If loading on simply supported pre-stressed concrete beam is uniformly distributed, then BMD of this beam will be parabolic with zero moment at supports and maximum bending moment at mid span, hence; the profile of cable will be parabola with zero eccentricity at ends and maximum eccentricity at mid span (See figure II).
Answer is Parabolic, with convexity downward.
