A. bn (fc/2) (d – n/3)
B. Atft (d – n/3)
C. ½ n1 (1 – n1/3) cbd²
D. All the above
Related Mcqs:
- 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 - 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__________________?
A. 0.496 %
B. 0.596 %
C. 0.696 %
D. 0.796 %
- 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 - 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 - In a doubly-reinforced beam if and the effective depth and is depth of critical neutral axis, the following relationship holds good______________?
A. mc/t = n/(d – n)
B. (m + c)/t = n/(d + n)
C. (t + c)/n = (d + n)/n
D. mc/t = (d – n)/t - 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 - 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
- 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 - In a singly reinforced beam, the effective depth is measured from its compression edge to_________________?
A. Tensile edge
B. Tensile reinforcement
C. Neutral axis of the beam
D. Longitudinal central axis - An intermediate T-beam reinforced with two layers of tensile steel with clear cover 13 cm encasted with the floor of a hall 12 metres by 7 metres, is spaced at 3 metres from adjoining beams and if the width of the beam is 20 cm, the breadth of the flange is__________________?
A. 300 cm
B. 233 cm
C. 176 cm
D. 236 cm
