Question

For the structure shown below, the vertical deflection at point $A$ is given by

• A. $\frac{P{L}^3}{81EI}$
• B. $\frac{2P{L}^3}{81EI}$
• C. Zero
• D. $\frac{P{L}^3}{72EI}$

Answer 1

The correct option is C Zero

Loading of horizontal top member:

$\delta =\frac{P(3L{)}^3}{3EI}-\frac{\left(2PL\right)(3L{)}^2}{2EI}$
$=\frac{27P{L}^3}{3EI}-\frac{9P{L}^3}{EI}=0$