For the doubly reinforced beam section shown below (with tension on the bottom), find the values and

plot the moment-curvature relationship at the following points:

a) Just prior to cracking.

b) When the tension steel has yielded based on strain at the centroid of the bar (The yield moment,

My).

c) When the tension steel has reached 1.5 times yield strain.

d) At ultimate when concrete crushes (The nominal moment, Mn).

e) When the beam is subjected to an applied moment that is 75% of the nominal moment (from part

d).