If the depth of actual neutral axis of a doubly reinforced beam

A singly reinforced beam has breadth b, effective depth d, depth of neutral axis n and critical neutral axis n?. If fc and ft are permissible compressive and tensile stresses, the moment to resistance of the beam, is

A

bn (fc/2) (d - n/3)

B

Atft (d - n/3)

C

½ n₁ (1 - n₁/3) cbd²

D

All the above

A singly reinforced beam has breadth b, effective depth d, depth of neutral axis n and critical neutral axis n₁. If f_c and f_t are permissible compressive and tensile stresses, the moment to resistance of the beam, is

A

$${\text{bn}}\frac{{{{\text{f}}_{\text{c}}}}}{2}\left( {{\text{d}} - \frac{{\text{n}}}{3}} \right)$$

B

$${\text{At}}{{\text{f}}_{\text{t}}}\left( {{\text{d}} - \frac{{\text{n}}}{3}} \right)$$

C

$$\frac{1}{2}{{\text{n}}_1}\left( {1 - \frac{{{{\text{n}}_1}}}{3}} \right){\text{cb}}{{\text{d}}^2}$$

D

All the above

If the depth of actual neutral axis in a beam is more than the depth of critical neutral axis, then the beam is called

A

Balanced beam

B

Under reinforced beam

C

Over reinforced beam

D

None of the above

When the depth of the actual neutral axis in a beam is greater than the depth of the critical neutral axis, then the beam is called:

A

under-reinforced section

B

balanced beam section

C

critical section

D

over-reinforced section

In a doubly-reinforced beam if ‘c’ and ‘t’ are stresses in concrete and tension reinforcement, ‘d’ is the effective depth and ‘n’ is depth of critical neutral axis, the following relationship holds good

A

$$\frac{{{\text{mc}}}}{{\text{t}}} = \frac{{\text{n}}}{{{\text{d}} - {\text{n}}}}$$

B

$$\frac{{{\text{m}} + {\text{c}}}}{{\text{t}}} = \frac{{\text{n}}}{{{\text{d}} + {\text{n}}}}$$

C

$$\frac{{{\text{t}} + {\text{c}}}}{{\text{m}}} = \frac{{{\text{d}} + {\text{n}}}}{{\text{n}}}$$

D

$$\frac{{\text{m}}}{{{\text{t}} + {\text{c}}}} = \frac{{\text{n}}}{{{\text{d}} - {\text{n}}}}$$

In case of an under-reinforced beam, the depth of actual neutral axis is __________ that of the critical neutral axis.

A

Same as

B

Less than

C

Greater than

D

None of these

Identify the option which holds true in the case of the depth of the neutral axis of a doubly reinforced beam.

A

If it is less than the depth of critical neutral axis, the concrete attains its maximum stress earlier

B

If it is greater than the depth of critical neutral axis, the concrete attains its maximum stress earlier

C

If it is greater than the depth of critical neutral axis, the steel in the tensile zone attains its maximum stress earlier

D

If it is less than the depth of critical neutral axis; the concrete and steel attain their maximum stresses simultaneously

Consider the following statements regarding stress in beam : 1. If a member is subjected to equal and opposite couples acting in the same longitudinal planes, the member is said to be in pure bending. 2. The internal stresses developed in the beam are known as flexural stresses. 3. There is an intermediate surface known as neutral surface, at which the stress is zero. 4. An axis obtained by intersection of the neutral surface and a cross-section is known as neutral axis. Which of the above statements are correct ?

A

2 and 3 only

B

1 and 4 only

C

3 and 4 only

D

1, 2, 3 and 4

Consider the following statements with regards to the shear force diagram for the beam ABCD: 1. The beam ABCD is an overhanging beam having supports at A and D only. 2. The beam carries a point load of 20 kN at C. 3. The beam carries a concentrated load of 10 kN at the end B. 4. The beam is an overhanging beam having supports at C and D only. 5. The beam carries a uniformly distributed load of 70 kN over the left hand portion AC only. Which of the above statements are correct?

A

1, 2 and 3 only

B

1, 3 and 5 only

C

2, 3 and 4 only

D

2, 4 and 5 only

If d and n are the effective depth and depth of the neutral axis respectively of a singly reinforced beam, the lever arm of the beam, is

A

d

B

n

C

$${\text{d}} + \frac{{\text{n}}}{3}$$

D

$${\text{d}} - \frac{{\text{n}}}{3}$$

If the depth of actual neutral axis of a doubly reinforced beam

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