Chapter 14 : Analysis of Perfect Frames (Graphical Method) 321
- Fig. 14.57 shows a truss pin-joint at one end, and freely supported at the other. It carries
loads as shown in the figure. Determine forces in all the members of the truss and state their nature.
Ans. AB = 2.0 kN (Compression)
BC = 0.9 kN (Compression)
CD = 2.1 kN (Compression)
AF = 0.7 kN (Compression)
BF = 1.2 kN (Tension)
CF = 2.3 kN (Compression)
FE = 1.3 kN (Tension)
CE = 0
ED = 1.3 kN (Tension)QUESTIONS
- Discuss the procedure for drawing the vector diagram of a frame.
- How will you find out (i) magnitude of a force, and (ii) nature of a force from the vector
diagram? - What is a cantilever truss? How will you find out its reactions?
- Explain why it is not essential to obtain the reactions of a cantilever truss before drawing
the vector diagram? - Describe the procedure for drawing the vector diagram of a truss subjected to horizontal
loads.
OBJECTIVE QUESTIONS
- The space diagram of a framed structure must have all the
(a) loads (b) reactions (c) both (a) and (b) - The Bow’s notations is used only in case of
(a) simply supported structure
(b) cantilever structure
(c) structures with one end hinged and the other supported on rollers.
(d) all of the above. - If in a vector diagram, any two points coincide, then the force in the member represented
by the two letters is zero.
(a) True (b) False - In a graphical method, for analysing the perfect frames, it is possible to check the previous
work in any subsequent step.
(a) Yes (b) No
ANSWERS
- (c) 2. (d) 3. (a) 4. (a)
Fig. 14.57.1kN2kN1kNABCD
F E90° 90° 30°4m 4m 4mTop