Structural Analysis Multiple Choice Questions on “Live Load Reduction”.
1. If influence area contributing to a particular load increases, then what happens to the possibility of having full design load on each square meter of area?
a) Increases
b) Decreases
c) Doesn’t affect
d) Depends on case
Answer: b
Clarification: As area increases, likelihood of having max. Load decreases due to known forces.
2. Building codes usually permit reduction in live load when small areas are concerned.
State whether this statement is true or false
a) True
b) False
Answer: b
Clarification: Possibility of having maximum live load decreases as area increases. So, reduction in live load is permitted in cases of large area, not small area.
3. Reduction factors given in Section 4.8 of ASCE 7-02 & in Section 1607.9.1 of IBC-2003 are:-
a) Different
b) Same
c) Vary in some cases
d) There is no reduction factor in Section 4.8 of ASCE 7-02
Answer: b
Clarification: Both have same reduction factor which is L = Lo(0.25 + (15/((KLL*AT)0.5))).
4. What is the minimum limit of influence area (in sq. ft) till which live loads can be reduced?
a) 100
b) 200
c) 300
d) 400
Answer: d
Clarification: From the equation of reduction factor, it can be shown that the lower limit is 400sq.ft.
5. In the case of a structural member supporting more than one floor with load exceeding 100psf., what is the maximum permitted reduction %?
a) 10
b) 15
c) 20
d) 25
Answer: c
Clarification: In buildings supporting more than one floor, studies have shown that rarely it is loaded (a floor) with more than 80% of its design load.
6. Loads used to obtain column design forces and to obtain beam design forces are:-
a) Necessarily same
b) Necessarily different
c) Most likely same
d) Most likely different
Answer: d
Clarification: This happens because the reduction factor are most likely to be different.
7. When column supports the top floor of a building, then live load reduction is:-
a) Permitted
b) Not permitted
c) Depends upon type of beam
d) Depends upon amount of load
Answer: b
Clarification: When column support a floor, it should be thought of as supporting a single floor only.
8. Live load element factor KLL remains constant for all types of structure.
State whether this statement is true or false.
a) True
b) False
Answer: b
Clarification: Live load element factor KLL depends upon type of structure in question.