Analysis the rigid jointed plane frame

Degree of Static Indeterminancy.

Ds = R-E = 4-3 = 1

Assuming Ds = Number of redundant force R

Portion	Origin	Limit	Mxx	M1
DC	D	0-2	0	0
BC	C	0-4	-10X²/2 = -5X²	+X
BA	B	0-5	-20X – 1042 = -20X-80	4

Actual displacement at redundant = 0

[ D ] = [ ΔL1 ] + δ11 * R1

0 = - 2920 / EI + 101.33 / EI * R1

R1 = 2920 / 101.33 = 28.21 KN