Engineering Mechanics

(^304) „„„„„ A Textbook of Engineering Mechanics
Example 14.10. Figure 14.25 shows a cantilever truss having a span of 4.5 metres. It is
hinged at two joints to a wall and is loaded as shown.
Fig. 14.25.
Find the reactions and forces in the members of the truss.
Solution. First of all, draw the space diagram and name all the members and forces accord-
ing to Bow’s notations as shown in Fig. 14.26 (a).
Fig. 14.26.
Now draw the vector diagram as shown in Fig. 14.26 (b) starting from the joint D. Measuring
various sides of the vector diagram the results are tabulated here :
S.No. Member Magnitude of force in kN Nature of force
1 AB (1-5) 4750 Tension
2 BC (2-7) 3160 Tension
3 CD (3-9) 1580 Tension
4 DE (4-9) 1500 Compression
5 CE (8-9) 0 —
6 EF (4-8) 1500 Compression
7 CF (7-8) 1580 Compression
8 BF (6-7) 500 Tension
9 FG (4-6) 3080 Compression
10 BG (5-6) 1800 Compression
Reaction
Upper RA (1-5) = 4750 kN
Lower RG (4-5) = 4600 kN