This set of Structural Analysis Multiple Choice Questions & Answers (MCQs) focuses on “Analysis of Externally Redundant Trusses”.
1. Externally redundant truss can be solved by three equilibrium equations.
a) True
b) False
View Answer
Explanation: Redundant truss is solved by using equilibrium equations along with the displacement equilibrium.
2. Calculate the P value of the member AC for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 1kN
b) 3kN
c) 5.77kN
d) 2.89kN
View Answer
Explanation:
Va=Vb (Due to symmetry)
Va=Vb=5kN
At joint A,
∑V=Fac sin θ=5kN
Fac=\(\frac{5}{sin60}\)=5.77kN.
3. Calculate the P value of the member AC for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 1kN
b) 3kN
c) 5.77kN
d) 2.89kN
View Answer
Explanation:
Va=Vb (Due to symmetry)
Va=Vb=5kN
At joint A,
∑V=Fac sinθ=5kN
Fac=\(\frac{5}{sin60}\)=5.77kN
Fac cosθ=Fab=5.77*cos60=2.89kN.
4. Calculate the P value of the member BC for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 1kN
b) 3kN
c) 5.77kN
d) 2.89kN
View Answer
Explanation:
Va=Vb (Due to symmetry)
Va=Vb=5kN
At joint B,
∑V=Fbc sinθ=5kN
Fbc=\(\frac{5}{sin60}\)=5.77kN.
5. Calculate the k value of the member BC for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 0kN
b) 1kN
c) 2.89kN
d) 3kN
View Answer
Explanation: If the support reaction at support is considered 1kN rightward, the horizontal force at the joint will be balanced by horizontal force in member AB. Thus, member BC becomes a zero-force member.
6. Calculate the k value of the member AC for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 0kN
b) 1kN
c) 2.89kN
d) 3kN
View Answer
Explanation: If the support reaction at support A is considered 1kN leftward, the horizontal force at the joint will be balanced by horizontal force in member AB. Thus, member AC becomes a zero-force member.
7. Calculate the k value of the member AB for the given external redundant truss, considering the horizontal reaction of support B as a redundant force.
a) 0kN
b) 1kN
c) 2.89kN
d) 3kN
View Answer
Explanation: If the support reaction at support is considered 1kN leftward, the horizontal force at the joint will be balanced by horizontal force in member AB. Thus, member AC becomes a zero-force member.
8. Calculate the redundant horizontal forces at support B, for the given truss considering the horizontal reaction of support B as a redundant force.
a) 1kN
b) 5kN
c) 3kN
d) 2.89kN
View Answer
Explanation:
| Member | P values | k values | Length of Member | \(\frac{P k L}{AE}\) | \(\frac{∑k^2 L}{AE}\) |
|---|---|---|---|---|---|
| AB | 2.89 | 1 | 3 | 8.67 | 3 |
| BC | -5.77 | 0 | 3 | 0 | 0 |
| AC | -5.77 | 0 | 3 | 0 | 0 |
Redundant horizontal force at support B=\(\frac{- ∑\frac{P k L}{AE}}{\frac{∑k^2 L}{AE}}\) = -2.89kN
9. Calculate the force in the member AB for the given truss.
a) 0kN
b) 2.89kN
c) 5.78kN
d) 10kN
View Answer
Explanation:
| Member | P values | k values | Length of Member | \(\frac{P k L}{AE}\) | \(\frac{∑k^2 L}{AE}\) |
|---|---|---|---|---|---|
| AB | 2.89 | 1 | 3 | 8.67 | 3 |
| BC | -5.77 | 0 | 3 | 0 | 0 |
| AC | -5.77 | 0 | 3 | 0 | 0 |
Redundant horizontal force at support B=\(\frac{- ∑\frac{P k L}{AE}}{\frac{∑k^2 L}{AE}}\) = 2.89kN(leftward)
Considering, joint B
∑H=0
2.89-2.89+Fab=0
Fab=0 kN.
10. Externally redundant trusses are always internally determinate.
a) True
b) False
View Answer
Explanation: There is no dependency among the external and internal indeterminacy of a truss. If a truss is externally indeterminate, it can be either internally determinate or indeterminate.
Sanfoundry Global Education & Learning Series – Structural Analysis.
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