If the permissible compressive and tensile stresses in a singly reinforced beam are 50 kg/cm2 and 1400 kg/cm2 respectively and the modular ratio is 18, the percentage area At of the steel required for an economic section, is__________________?

Related Mcqs:

1. If permissible working stresses in steel and concrete are respectively 1400 kg/cm2 and 80 kg/cm2 and modular ratio is 18, in a beam reinforced in tension side and of width 30 cm and having effective depth 46 cm, the lever arms of the section, is______________?

   A. 37 cm

   B. 38 cm

   C. 39 cm

   D. 40 cm

2. A singly reinforced beam has breadth b, effective depth d, depth of neutral axis n and critical neutral axis n1. 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

3. A short column 20 cm × 20 cm in section is reinforced with 4 bars whose area of cross section is 20 sq. cm. If permissible compressive stresses in concrete and steel are 40 kg/cm2 and 300 kg/cm2, the Safe load on the column, should not exceed_______________?

   A. 4120 kg
   B. 41,200 kg
   C. 412,000 kg
   D. None of these

4. A simply supported beam 6 m long and of effective depth 50 cm, carries a uniformly distributed load 2400 kg/m including its self weight. If the lever arm factor is 0.85 and permissible tensile stress of steel is 1400 kg/cm2, the area of steel required, is___________________?

   A. 14 cm 2
   B. 15 cm2
   C. 16 cm2
   D. 17 cm2

5. A singly reinforced concrete beam of 25 cm width and 70 cm effective depth is provided with 18.75 cm2 steel. If the modular ratio (m) is 15, the depth of the neutral axis, is_________________?

   A. 20 cm
   B. 25 cm
   C. 30 cm
   D. 35 cm

6. In a singly reinforced beam, if the permissible stress in concrete reaches earlier than that in steel, the beam section is called________________?

   A. Under-reinforced section
   B. Over reinforced section
   C. Economic section
   D. Critical section

7. The stresses developed in concrete and steel in reinforced concrete beam 25 cm width and 70 cm effective depth, are 62.5 kg/cm2 and 250 kg/cm 2 respectively. If m = 15, the depth of its neutral axis is_______________?

   A. 20 cm
   B. 25 cm
   C. 30 cm
   D. 35 cm

8. The section of a reinforced beam where most distant concrete fibre in compression and tension in steel attains permissible stresses simultaneously, is called_________________?

   A. Balanced section
   B. Economic section
   C. Critical section
   D. All the above

9. effective depth and depth of the neutral axis respectively of a singly reinforced If d and n are the beam, the lever arm of the beam, is_________________?

   A. d
   B. n
   C. d + n/3
   D. d – n/3

10. If the modular ratio is , steel ratio is and overall depth of a beam is , the depth of the critical neutral axis of the beam, is___________________?

    A. [m/(m – r)] d
    B. [m/(m + r)] d
    C. [(m + r)/ m] d
    D. [(r – m)/m] d