RCC Structures Design

141. is the pre-stressed force applied to the tendon of a rectangular pre-stressed beam whose area of cross section is and sectional modulus is . The maximum stress in the beam, subjected to a maximum bending moment , is

1. f = (P/A) + (Z/M)
2. f = (A/P) + (M/Z)
3. f = (P/A) + (M/Z)
4. f = (P/A) + (M/6Z)

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142. Lapped splices in tensile reinforcement are generally not used for bars of size larger than

1. 18 mm diameter
2. 24 mm diameter
3. 30 mm diameter
4. 36 mm diameter

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143. Long and short spans of a two way slab are ly and lx and load on the slab acting on strips parallel to lx and ly be wx and wy respectively. According to Rankine Grashoff theory

1. (w_x/w_y) = (l_y/l_x)
2. (w_x/w_y) = (l_y/l_x)²
3. (w_x/w_y) = (l_y/l_x)⁴
4. None of these

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144. Minimum spacing between horizontal parallel reinforcement of different sizes, should not be less than

1. One diameter of thinner bar
2. One diameter of thicker bar
3. Twice the diameter of thinner bar
4. None of these

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145. Minimum spacing between horizontal parallel reinforcement of the same size should not be less than

1. One diameter
2. 2.5 diameters
3. 3 diameters
4. 3.5 diameters

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146. On an absolutely rigid foundation base, the pressure will

1. Be more at the edges of the foundation
2. Be uniform
3. Not be uniform
4. Be zero at the centre of the foundation

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147. On piles, the drop must be at least

1. 80 cm
2. 100 cm
3. 120 cm
4. 140 cm

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148. 'p' is the pre-stressed force applied to tendon of a rectangular pre-stressed beam whose area of cross section is 'A' and sectional modulus is 'Z'. The minimum stress 'f' on the beam subjected to a maximum bending moment 'M' is

1. f = (P/A) - (Z/M)
2. f = (A/P) - (M/Z)
3. f = (P/A) - (M/Z)
4. f = (P/A) - (M/6Z)

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149. Pick up the assumption for the design of a pre-stressed concrete member from the following:

1. A transverse plane section remains a plane after bending
2. During deformation limits, Hook's law is equally applicable to concrete as well as to steel
3. Variation of stress in reinforcement due to changes in external loading is negligible
4. All the above

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150. Pick up the correct statement from the following:

1. Lateral reinforcement in R.C.C. columns is provided to prevent the longitudinal reinforcement from buckling
2. Lateral reinforcement prevents the shearing of concrete on diagonal plane
3. Lateral reinforcement stops breaking away of concrete cover, due to buckling
4. All the above

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