Question

What will be the rotation under the left load for the beam shown below:

• A. $\frac{125}{EI}$
• B. $\frac{175}{EI}$
• C. $\frac{225}{EI}$
• D. $\frac{250}{EI}$

Answer 1

The correct option is C $\frac{225}{EI}$


Reaction in conjugate beam =
$-\frac{1}{2}[(2\times \frac{1}{2}\times \frac{150}{EI}\times 3)+(\frac{150}{EI}\times 3)]=-\frac{450}{EI}$
Slope at mid point of beam = shear force in conjugate beam under the load.
$=-\frac{450}{EI}+(\frac{1}{2}\times \frac{150}{EI}\times 3)=-\frac{225}{EI}$
NOTE : - If shear in conjugate beam is positive, then rotation is anticlockwise.