ANALYSIS OF BEAMS BY

STIFFNESS METHOD

1

General Stiffness Matrix

Free body diagram

3 1

General Stiffness Matrix

- -

-

3 4 5 2

2

5 2 1 6

1 2 3 4 5 6

1 2 3 4 5 6

8 = EI/8 (4D1 + 2D2 +0) …………………… (I)

0 = EI/8 (2D1 + 8D2 +2D3) …………………… (2)

-8 = EI/8 (0 + 2D2 +4D3) …………………… (2)

By solving the equations

D1 = 16/EI

D2 = 0

D3 = -16/EI

Q1 = 25.5 k

Q2 = 21 k

Q3 = 25.5 k