Structural Analysis Multiple Choice Questions on “Beams & Frames Static Indeterminacy”.
1. The number of equilibrium equations for the following space frame is ________
a) 1
b) 3
c) 6
d) 4
Answer: c
Clarification: There are six equilibrium equations available for space frames are as follows ∑Fx=0, ∑Fy=0, ∑Fz=0, ∑Mx=0, ∑My=0, and ∑Mz = 0.
2. Which of the following is statically determinate structure?
a) Fixed beam
b) Continuous beam
c) Two hinged arch
d) Double overhanging
Answer: d
Clarification: Double overhanging can be analysed by available three equilibrium equations i.e. ∑Fx=0, ∑Fy=0, and ∑M = 0.
3. External Static Indeterminacy of the following beam is _______
a) 2
b) 4
c) 3
d) 0
Answer: c
Clarification: This is case of vertical loading only. Static indeterminacy = (2+2+1)–2 = 3.
4. External Static Indeterminacy for the following frame is _____
a) 0
b) 3
c) 4
d) 6
Answer: b
Clarification: Frames are always of General loading case. Static indeterminacy = (3+3)–3=3.
5. External Static Indeterminacy for the following space frame is ________
a) 18
b) 9
c) 6
d) 10
Answer: a
Clarification: This is space frame. Thus, fixed end will have six reactions and available equilibrium equations are also 6. Therefore, External Static Indeterminacy = (6+6+6+6)-6 = 18.
6. Internal Static Indeterminacy for the following space frame is _____
a) 18
b) 9
c) 6
d) 10
Answer: c
Clarification: Internal static indeterminacy of space frame = 6 * no of boxes the structure has. Therefore, Internal static indeterminacy = 6*1 = 6.
7. Force release for the following space frame is _____
a) 3
b) 2
c) 6
d) 0
Answer: c
Clarification: Force release for space frame is given by 3(m-1), where m is the no of member joining at hinged end. Therefore, Force release = 3(3-1) = 3*2 = 6.
8. Static Indterminacy for the following space frame is _____
a) 18
b) 9
c) 6
d) 0
Answer: a
Clarification: Static Equilibrium = External Static Indeterminacy + Internal static indeterminacy – Internal static indeterminacy. Therefore Static Equilibrium = 18 + 6 – 6 = 18.
9. Static Indeterminacy for rigid jointed plane frame is given by __________
a) (m + r) – 2j
b) (m + r) – 3j
c) (3m + r) -3j
d) (6m + r) – 6j
Answer: c
Clarification: Static Indeterminacy for rigid jointed plane frame is given by (3m + r) -3j. Where m, r and j stands for number of members, reactions and number of joints respectively.
10. Stresses will develop due to change in temperature in statically determinate structure.
a) True
b) False
Answer: b
Clarification: Stresses will develop due to change in temperature, sinking of support and lack of fit in statically indeterminate structure only.