This set of Design of RC Structures Multiple Choice Questions & Answers (MCQs) focuses on “Singly Reinforced Beams – Lever Arm”.
1. Zero lever arm must exist in the case of reinforced beams.
a) True
b) False
View Answer
Explanation: There are separate tension and compression zones therefore zero lever arm does not exist in the case of reinforced beams.
2. What is the distance between line of action of resultant compression and line of action of resultant tension called?
a) Neutral Axis
b) Lever Arm
c) Centroid
d) Centroidal Axis
View Answer
Explanation: The distance through which the compression and tension forces in a beam tend to rotate it is called as Lever Arm.
3. In what case will lever arm be zero?
a) M = 0
b) M = 1
c) M is positive
d) M is negative
View Answer
Explanation: Moment = Force * Lever Arm
Lever Arm = Moment/Force
So, if M = 0 than Lever Arm = 0
4. What do you understand by the following diagram?
a) Intensity of compressive stress varies from maximum at the top to zero at the neutral axis
b) Intensity of compressive stress varies from minimum at the top to maximum at the neutral axis
c) Stress is maximum at all places
d) Nature of stress can’t be determined by the given data
View Answer
Explanation: centre of gravity of the compressive force is at a distance x/3 from the top edge of the section.
Therefore, z = d-x/3
- Intensity of compressive stress varies from maximum at the top to zero at the neutral axis.
5. Find the lever arm for a rectangular beam of effective depth 250mm. Take σcbc = 5N/mm2 and σst = 140N/mm2.
a) 200.5
b) 220.5
c) 217.5
d) 250.5
View Answer
Explanation: σcbc / (σst/m) = xc / (d – xc)
xc = 100mm
z = d – xc/3
z = 217.5
6. The effect of air entrained in concrete is ____
a) Decrease in strength
b) Increase in workability
c) Increase in strength
d) Decrease in workability
View Answer
Explanation: The air Entrained in the concrete increases the workability of concrete.
7. The shape of aggregate which is best for interlocking is ________
a) Angular
b) Rounded
c) Elongated
d) Edgy
View Answer
Explanation: Angular shaped aggregate increases the interlocking in concrete as cement is easily bounded on it.
8. The alternate formula for lever arm is _____
a) a = at/3
b) a = atd
c) a = at/d
d) a = 3at
View Answer
Explanation: Sometimes the lever arm is expressed as the product of a coefficient at and the effective depth.
9. Lever Arm is directly proportional to Moment.
a) True
b) False
View Answer
Explanation: Bending Moment = Force * Lever Arm
So Lever Arm is directly proportional to Moment.
10. The larger the lever arm, the section becomes more ______
a) Brittle
b) Elastic
c) Economic
d) Ductile
View Answer
Explanation: The larger the lever arm, the section becomes more ductile but it would have less moment resistance.
Sanfoundry Global Education & Learning Series – Design of RC Structures
To practice all areas of Design of RC Structures, here is complete set of 1000+ Multiple Choice Questions and Answers.
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