Question 1

If is the load on a circular slab of radius , the maximum radial moment at the centre of the slab, is

Accepted Answer

The maximum radial moment at the center of a circular slab, given a uniform load W, is calculated as 3WR²/16. This is derived from the formulas used in structural engineering for analyzing circular slabs under uniform loads.

Question 2

If A is the area of the foundation of a retaining wall carrying a load W and retaining earth of weight w per unit volume, the minimum depth (h) of the foundation from the free surface of the earth, is

Accepted Answer

C

Question 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

Accepted Answer

C

Question 4

The modular ratio m of a concrete whose permissible compressive stress is C, may be obtained from the equation.

Accepted Answer

The modular ratio m is given by the formula m = 2800/3C, which is derived from the relationship between the modulus of elasticity of steel and concrete, considering the permissible compressive stress C of the concrete.

Question 5

If is the sectional area of a pre-stressed rectangular beam provided with a tendon pre-stressed by a force through its centroidal longitudinal axis, the compressive stress in concrete, is

Accepted Answer

The compressive stress in concrete due to a pre-stressing force (P) applied through the centroidal longitudinal axis of a rectangular beam is given by the formula σ = P/A, where σ is the stress, P is the pre-stressing force, and A is the sectional area of the beam.

Question 6

A pre-stressed rectangular beam which carries two concentrated loads W at L/3 from either end, is provided with a bent tendon with tension P such that central one-third portion of the tendon remains parallel to the longitudinal axis, the maximum dip his

Accepted Answer

The maximum dip of the tendon in a pre-stressed beam with the given loading condition is determined by balancing the moments. The correct formula for the maximum dip is WL/3P, which ensures that the tendon profile provides the necessary counteracting moment to balance the applied loads.

Question 7

If q is the punching shear resistance per unit area a, is the side of a square footing for a column of side b, carrying a weight W including the weight of the footing, the depth (D) of the footing from punching shear consideration, is

Accepted Answer

Punching shear resistance is a measure of the ability of a material to withstand a punching shear force. The formula for the depth (D) of a footing from punching shear consideration, given the parameters in the question, is derived from the basic principles of equilibrium and stress distribution. The correct formula accounts for the difference in area between the square footing and the column (a² - b²), the weight W, and the punching shear resistance per unit area (q), leading to the formula D = W (a² - b²)/4a²bq. This formula correctly balances the dimensions and units to provide the depth needed to resist the punching shear force.

Question 8

For initial estimate for a beam design, the width is assumed

Accepted Answer

The answer of For initial estimate for a beam design,...

Question 9

If the length of a combined footing for two columns l metres apart is L and the projection on the left side of the exterior column is x, then the projection y on the right side of the exterior column, in order to have a uniformly distributed load, is (where is the distance of centre of gravity of column loads).

Accepted Answer

For a combined footing to have a uniformly distributed load, the center of gravity of the system must align with the geometric center of the footing. The projection y on the right side can be found by considering the symmetry and balance of the system. The correct formula is y = L/2 - (l - ), which accounts for the distance from the center of the footing to the exterior column, adjusted by the distance of the center of gravity of the column loads from the midpoint between the columns.

Question 10

Total pressure on the vertical face of a retaining wall of height h acts parallel to free surface and from the base at a distance of

Accepted Answer

The total pressure on the vertical face of a retaining wall acts at a distance of h/3 from the base, according to the principles of fluid pressure on surfaces.

Question 11

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

Accepted Answer

The stress at the extreme top edge is decreased by Pe/Z due to the eccentric placement of the tendon, which creates a moment that counteracts the stress at the top edge.

Question 12

Design of a two way slab simply supported on edges and having no provision to prevent the corners from lifting, is made by

Accepted Answer

Rankine Grashoff formula is used for the design of a two way slab simply supported on edges and having no provision to prevent the corners from lifting.

Question 13

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

Accepted Answer

All the options listed are assumptions commonly made in the design of pre-stressed concrete members. These assumptions simplify the analysis and design process by providing a basis for calculating stresses and deformations in the material. Option A assumes that plane sections before bending remain plane after bending, which is a fundamental assumption in bending theory. Option B assumes that both concrete and steel follow Hooke's law within certain deformation limits, allowing for a linear relationship between stress and strain. Option C assumes that the variation of stress in the reinforcement due to changes in external loading is negligible, simplifying the analysis of pre-stressed members under varying loads.

Question 14

An R.C.C. column is treated as short column if its slenderness ratio is less than

Accepted Answer

The answer of An R.C.C. column is treated as short...

Question 15

The zone in which transverse bending is likely to occur may be obtained by drawing a line from the

Accepted Answer

The zone in which transverse bending is likely to occur may be obtained by drawing a line from the 45° angle. This is a common practice in engineering to identify areas susceptible to bending stresses.

Question 16

If the length of an intermediate span of a continuous slab is 5m, the length of the end span is kept

Accepted Answer

For a continuous slab, the length of the end span is typically kept at 0.7 to 0.8 times the length of the intermediate span to ensure a more uniform moment distribution and to reduce the negative moment at the support. For an intermediate span of 5m, 0.9 times the length would be 4.5m, making option A the correct choice.

Question 17

If L is the effective span of a R.C.C. beam which is subjected to maximum shear qmax at the ends, the distance from either end over which stirrups for the shear, are provided, is

Accepted Answer

The distance from the ends over which stirrups are provided is calculated using the formula (L/2) (1 - 5/qmax) to ensure adequate shear reinforcement where shear forces are significant.

Question 18

The angle of internal friction of soil mass is the angle whose

Accepted Answer

The angle of internal friction of a soil mass is defined by the tangent of the angle, which is equal to the ratio of the maximum resistance to sliding on any internal inclined plane to the normal pressure acting on the plane. This is a fundamental property in soil mechanics related to shear strength.

Question 19

If T and R are the tread and rise of a stair which carries a load w per square metre on slope, the corresponding load per square metre of the horizontal area, is

Accepted Answer

The correct formula to convert the load per square metre on the slope to the load per square metre of the horizontal area is by considering the hypotenuse of the triangle formed by the tread and the rise. The formula is $w \times \frac{\sqrt{R^2 + T^2}}{T}$, which simplifies to option B: $w \times \frac{R^2 + T^2}{T}$ when considering the area conversion.

Question 20

If the maximum dip of a parabolic tendon carrying tension P is h and the effective length of the pre-stressed beam is L, the upward uniform pressure will be

Accepted Answer

The upward uniform pressure (w) exerted by a parabolic tendon in a prestressed beam can be calculated using the formula w = 8Ph/L², where P is the tension in the tendon, h is the maximum dip, and L is the effective length of the beam. Therefore, the correct formula is represented by option B) 8hp/l².

Quiz 2: Civil Engineering Design and Analysis