(^316) A Textbook of Engineering Mechanics
Example 14.20. A truss hinged at A and supported on rollers at D is loaded as shown in
Fig. 14.49.
Fig. 14.49.
Find by any method the forces in all the members of the truss and mention the nature of forces.
*Solution. Since the truss is supported on rollers at the right end D, therefore reaction at this
support will be inclined at 45°, with the vertical (because the support is inclined at 45° with the
horizontal). Now find out the reactions as done in example 12.17. We know that horizontal component
of reaction at D.
RDH = RDV = 5.4 kN
and RAH = 5.4 kN and RAV = 1.6 kN
First of all, draw the space diagram and name the members and forces according to Bow’s
notations as shown in Fig. 14.50 (a).
Fig. 14.50.
Now draw the vector diagram as shown in Fig. 14.50 (b). Measuring the various sides of the
vector diagram, the results are tabulated here :
S.No. Member Magnitude of force in kN Nature of force
1 AB (2-7) 6.6 Compression
2 BC (2-8) 6.6 Compression
3 CD (2-10) 6.75 Compression
4 DE (4-10) 1.35 Compression
5 EF (5-9) 1.35 Compression
6 FA (6-7) 2.0 Tension
7 BF (7-8) 0 —
8 CF (8-9) 4.25 Tension
9 CE (9-10) 2.0 Tension
- We have already solved this example analytically in the last chapter.