Question

A steel frame is shown in the given figure.


If joint O of the frame is rigid, the rotational stiffness of the frame at point O is given by

• A. $\frac{10EI}{L}$
• B. $\frac{8EI}{L}$
• C. $\frac{6EI}{L}$
• D. $\frac{11EI}{L}$

Answer 1

The correct option is D $\frac{11EI}{L}$

Rotational stiffness is the ratio of moment and rotation at O. In other words rotational stiffness is the moment required for unit rotation at O.

$M=\frac{4EI}{L}+\frac{3EI}{L}+\frac{4EI}{L}=\frac{11EI}{L}$