Question

Considering the symmetry of a rigid frame as shown below the magnitude of the bending moment (in kNm) at C (using moment distribution method) is -

• A. 170
• B. 172
• C. 178
• D. 176

Answer 1

The correct option is D 176


axis of symmetry is passing through a column,
Hence it can be treated as

Member	Stiffness	DF
BA BC	$\frac{4EI}{6}$ $\frac{4E\left(4I\right)}{8}$	$\frac{1}{4}$ $\frac{3}{4}$

FEM
$M_{FBC}=-\frac{24\times 64}{12}=-128$

$M_{FBC}=128$


$\Rightarrow BMatC=176kNm$