1. Structural Mechanics 4 Shear Force, Bending Moment and Deflection of Beams
20 kN RA RB
3.00m
2.00m

2. Sum of moments about RA = 0
20 x (2.00) - RB x ( ) = 0
RB x (5.00) = 20 x (2.00)
RB = 20 x (2.00) / (5.00)
RB = 8.00 kN

3. Sum of moments about RB = 0
RA x ( ) x (3.00) = 0
RA x (5.00) = 20 x (3.00)
RA = 20 x (3.00) / (5.00)
RA = kN

4. So likely that calculations are correct!
CHECK VERTICAL FORCES
UPWARD REACTION = RB + RA = = 20 kN
DOWNWARD FORCE = 20 kN
So likely that calculations are correct!

5. SHEAR FORCE DIAGRAM 8kN 12kN 20 kN 12kN -8kN
Space diagram SHEAR FORCE DIAGRAM
20 kN
12kN
8kN
12kN
-8kN

6. BENDING MOMENT DIAGRAM
Space diagram
20 kN
12kN
8kN
24kNm
0kNm
12kN X 2m = 24 kNm
8kN X 3m = 24 kNm

7. 12kN 8kN 20 kN Deflection Max deflection at Max BM + 12kN SFD 24kNm
+ 12kN
SFD
BMD
24kNm
0kNm