‘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

A $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{Z}}}{{\text{M}}}$$
B $${\text{f}} = \frac{{\text{A}}}{{\text{P}}} - \frac{{\text{M}}}{{\text{Z}}}$$
C $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{M}}}{{\text{Z}}}$$
D $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{M}}}{{6{\text{Z}}}}$$

Correct Answer: $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{M}}}{{\text{Z}}}$$

Bissoy MCQ
#Civil Engineering #RCC Structures Design

Related Questions

‘P’ is the pre-stressed force applied to the tendon of a rectangular pre-stressed beam whose area of cross section is ‘A’ and sectional modulus is ‘Z’. The maximum stress ‘f’ in the beam, subjected to a maximum bending moment ‘M’, is
A $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{Z}}}{{\text{M}}}$$
B $${\text{f}} = \frac{{\text{A}}}{{\text{P}}} - \frac{{\text{M}}}{{\text{Z}}}$$
C $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{M}}}{{\text{Z}}}$$
D $${\text{f}} = \frac{{\text{P}}}{{\text{A}}} - \frac{{\text{M}}}{{6{\text{Z}}}}$$
If the tendon is placed at an eccentricity e below the centroidal axis of the longitudinal axis of a rectangular beam (sectional modulus Z and stressed load P in tendon) the stress at the extreme top edge
A Is increased by $$\frac{{{\text{PZ}}}}{{\text{e}}}$$
B Is increased by $$\frac{{{\text{Pe}}}}{{\text{Z}}}$$
C Is decreased by $$\frac{{{\text{Pe}}}}{{\text{Z}}}$$
D Remains unchanged
A shaft of diameter D is subjected to a twisting moment (T) and a bending moment (M). If the maximum bending stress is equal to maximum shear stress developed, then M is equal to
A $$\frac{{\text{T}}}{2}$$
B T
C 2T
D 4T
If ‘A’ is the sectional area of a pre-stressed rectangular beam provided with a tendon pre-stressed by a force ‘P’ through its centroidal longitudinal axis, the compressive stress in concrete, is
A $$\frac{{\text{P}}}{{\text{A}}}$$
B $$\frac{{\text{A}}}{{\text{P}}}$$
C $$\frac{{\text{P}}}{{2{\text{A}}}}$$
D $$\frac{{2{\text{A}}}}{{\text{P}}}$$
A shaft is subjected to bending moment M and a torque T simultaneously. The ratio of the maximum bending stress to maximum shear stress developed in the shaft, is
A $$\frac{{\text{M}}}{{\text{T}}}$$
B $$\frac{{\text{T}}}{{\text{M}}}$$
C $$\frac{{2{\text{M}}}}{{\text{T}}}$$
D $$\frac{{2{\text{T}}}}{{\text{M}}}$$
The bending moment ‘M’ and a torque ‘T’ is applied on a solid circular shaft. If the maximum bending stress equals to maximum shear stress developed, then ‘M’ is equal to
A $$\frac{{\text{T}}}{2}$$
B 1T
C 2T
D 4T
The ratio of maximum shear stress developed in a rectangular beam and a circular beam of the same cross-sectional area is
A $$\frac{2}{3}$$
B $$\frac{3}{4}$$
C 1
D $$\frac{9}{8}$$
The bending moment at a section tends to bend or deflect the beam and the internal stresses resist its bending. The resistance offered by the internal stresses, to the bending, is called
A Compressive stress
B Shear stress
C Bending stress
D Elastic modulus
When a beam of rectangular cross-section of width b and depth d, is subjected to a shear force F, the maximum shear stress induced will be
A $$\frac{{\text{F}}}{{{\text{bh}}}}$$
B $$\frac{{{\text{3F}}}}{{{\text{2bh}}}}$$
C $$\frac{{{\text{2F}}}}{{{\text{bh}}}}$$
D $$\frac{{{\text{4F}}}}{{{\text{bh}}}}$$
Two beams, one of circular cross-section and the other of square cross-section, have equal areas of cross-sections. When these beams are subjected to bending,
A Both beams are equally economical
B Square beam is more economical
C Circular beam is more economical
D None of these

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