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Question 1
ప్రశ్న 1
Which pairing correctly identifies the current IS 3370 Part 4 design-table sections used specifically for rectangular and circular reinforced concrete tanks?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 3370 Part 4 is divided into separate design-table sections. Section 2 deals specifically with rectangular tanks. Section 3 deals specifically with circular tanks. The separation reflects the different structural behaviour and analysis requirements of plate-type rectangular walls and cylindrical walls. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
Which statement best describes the behaviour of a rectangular RCC tank wall when its dimensions and edge restraints cause significant interaction with adjacent walls and the base?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Rectangular tank walls are interconnected plates rather than isolated strips in many practical configurations. Their vertical and horizontal spans and their restraints at adjoining walls, floor and roof affect the moment distribution. IS 3370 Part 4 Section 2 recognizes two-way plate action and also notes that in-plane axial compression or tension may develop. A one-way vertical cantilever approximation is appropriate only where the assumed geometry and restraint conditions justify it. Therefore Option B is correct.
వివరణ:
Question 3
ప్రశ్న 3
When using the IS 3370 Part 4 Section 2 coefficient tables for a rectangular tank, which information must be matched to the appropriate table?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The rectangular-tank design tables are organized according to loading configuration and end-restraint condition. Separate cases are provided for triangular and uniform loading. The tables also distinguish free or hinged top conditions and hinged or fixed base conditions. Appropriate tank dimensional ratios are required for selecting the relevant coefficient set. Therefore Option C is correct.
వివరణ:
Question 4
ప్రశ్న 4
According to the general assumptions in IS 3370 Part 4 Section 2, which design-table resource may be used for tanks having square plan dimensions where the applicable plate assumptions are satisfied?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 3370 Part 4 Section 2 specifically notes a useful simplification for square-plan tanks. The moment coefficients given in Part 4 Section 1 for plates may be used where the corresponding assumptions are applicable. This reflects the plate behaviour of walls in a square tank configuration. The circular-tank ring-tension tables are based on fundamentally different cylindrical behaviour. Therefore Option A is correct.
వివరణ:
Question 5
ప్రశ్న 5
A rectangular tank contains water to a depth of 4.0 m. Taking the unit weight of water as 10 kN/m³, what hydrostatic pressure acts at the bottom of the wall?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hydrostatic pressure at depth h is given by p = gamma h. The specified water unit weight is 10 kN/m³ and the depth is 4.0 m. Thus the bottom pressure is 10 × 4 = 40 kN/m². The pressure varies linearly from zero at the free water surface to this value at the bottom. Therefore Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
For the 4.0 m water depth in the previous question, what total hydrostatic thrust acts on a one-metre-wide vertical wall strip, and where does it act above the base?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The hydrostatic pressure diagram is triangular over the wall height. Its resultant is one-half of the base pressure multiplied by the water depth and unit width. Thus the thrust is 0.5 × 40 × 4 = 80 kN/m. The centroid of the triangle is located at H/3 above the base, which is approximately 1.33 m. Therefore Option B is correct.
వివరణ:
Question 7
ప్రశ్న 7
For an explicitly idealized long rectangular tank wall that is free at the top and fully fixed at the base, neglect horizontal plate action and treat a one-metre strip as a vertical cantilever retaining 4.0 m of water of unit weight 10 kN/m³. What is the base bending moment due to water pressure?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The stated idealization deliberately reduces the wall to a vertical cantilever strip. The resultant hydrostatic thrust is 80 kN/m and acts at 4/3 m above the base. The base moment is therefore 80 × 4/3 = 106.67 kN·m/m. Equivalently, the cantilever moment under triangular hydrostatic loading is gamma H cubed divided by 6. Therefore Option C is correct.
వివరణ:
Question 8
ప్రశ్న 8
For a rectangular tank wall, suppose the applicable analysis has supplied a dimensionless moment coefficient Mc = 0.045. The bottom pressure q is 40 kN/m² and loaded height H is 4.0 m. Using M = Mc q H² in consistent kN-m units, what moment per metre width is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The coefficient method converts the pressure and loaded height into the corresponding plate moment. The term qH² is 40 × 4² = 640 kN·m per metre width. Multiplying by the supplied coefficient gives 0.045 × 640 = 28.8 kN·m/m. Because the coefficient has already been supplied, no inaccessible design table is required to solve the question. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
An M30 rectangular tank wall strip 1000 mm wide has effective depth d = 200 mm and must resist a factored bending moment of 28.8 kN·m/m using Fe500 steel. Using the ordinary singly reinforced Limit State flexural equations, what strength reinforcement Ast is required approximately before the separate IS 3370 minimum-reinforcement and crack-control checks?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The strength calculation uses force equilibrium xu = 0.87fyAst divided by 0.36fckb. Moment capacity is then obtained from Mu = 0.87fyAst(d - 0.42xu). Substitution of b = 1000 mm, d = 200 mm, fck = 30 N/mm², fy = 500 N/mm² and Mu = 28.8 kN·m gives Ast of approximately 341 mm²/m. This is only the flexural-strength requirement and liquid-retaining minimum reinforcement or crack control may require more steel. Therefore Option B is correct.
వివరణ:
Question 10
ప్రశ్న 10
Why should the 341 mm²/m strength reinforcement calculated in the previous question not automatically be adopted as the final reinforcement of the tank wall?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Liquid-retaining construction is particularly sensitive to cracking and leakage. An area of steel that is sufficient only for ultimate flexural resistance may not provide acceptable serviceability performance. IS 3370 therefore includes dedicated requirements for minimum distributed reinforcement and crack control. The final reinforcement must satisfy both strength and the more demanding applicable serviceability provisions. Therefore Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
For a thin circular tank wall free to expand radially at the level considered and carrying an internal pressure p, what is the basic circumferential membrane tension per unit wall height for inside diameter D?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Consider equilibrium of one half of a thin cylindrical wall cut by a diametral vertical plane. The internal pressure acting on the projected diameter is resisted by circumferential tension at the two cut edges. This gives 2T = pD per unit height. Hence the membrane ring tension is T = pD/2. Therefore Option B is correct.
వివరణ:
Question 12
ప్రశ్న 12
At a particular depth in a circular water tank, the internal pressure is 30 kN/m² and the effective diameter used for membrane equilibrium is 8.0 m. What free-ring circumferential tension develops per metre height?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The free-ring membrane relation is T = pD/2. Substituting p = 30 kN/m² and D = 8.0 m gives T = 30 × 8/2. The resulting circumferential tensile force is 120 kN per metre height. Base and roof restraint can modify the actual ring tension and introduce bending near restrained regions. Therefore Option C is correct.
వివరణ:
Question 13
ప్రశ్న 13
For a particular verified circular-tank coefficient point, take Ftc = 0.60, liquid unit weight w = 10 kN/m³, loaded height H = 4.0 m and diameter D = 8.0 m. Using the IS 3370 coefficient relation Ft = Ftc wHD/2 for triangular liquid loading, what ring tension is obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The circular-tank coefficient relation incorporates the effect of restraint through Ftc. First, wHD/2 equals 10 × 4 × 8/2 = 160 kN/m. Multiplying this value by the supplied coefficient 0.60 gives Ft = 96 kN/m. The result differs from an unrestricted local membrane calculation because the coefficient represents the stated structural restraint condition. Therefore Option C is correct.
వివరణ:
Question 14
ప్రశ్న 14
Under IS 3370 Part 4 Section 3, which diameter D is used in the circular-wall coefficient equations?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The circular-tank coefficient equations define the diameter to be used rather than leaving it ambiguous. Where an impermeable lining is used, D is taken as the inside diameter. Otherwise, the code specifies the inside diameter plus the wall thickness. This definition affects ring-tension and related coefficient calculations. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
For a fixed-base circular tank under triangular liquid loading, suppose a verified moment coefficient at the section under consideration is Mc = -0.020. With w = 10 kN/m³ and H = 4.0 m, what wall moment follows from M = Mc wH³?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The coefficient relation for triangular loading is M = Mc wH³. The quantity wH³ equals 10 × 4³ = 640 kN·m/m. Multiplication by -0.020 gives -12.8 kN·m/m. The negative sign represents the sign convention associated with the supplied coefficient and therefore identifies the corresponding curvature or tension face. Therefore Option B is correct.
వివరణ:
Question 16
ప్రశ్న 16
What is the principal structural difference between idealized fixed-base and hinged-base conditions for a circular tank wall?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The terms fixed and hinged refer primarily to the rotational restraint assumed at the wall base. Fixity restrains rotation and therefore causes vertical wall bending moments to develop near the junction. A hinged idealization permits rotation and changes the vertical moment and ring-tension distribution. Circumferential tension does not disappear simply because the base is modeled as hinged. Therefore Option B is correct.
వివరణ:
Question 17
ప్రశ్న 17
For estimating hoop tension and vertical bending moments in a circular wall, what general assumption does IS 3370 Part 4 Section 3 permit at the wall top when no special roof continuity analysis is being made?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 3370 permits the top of a circular wall to be assumed free for estimating hoop tension and vertical bending moments. This means that radial and rotational restraint at the top is neglected in that basic wall analysis. The code notes that the assumption is conservative and generally makes little difference except near the top where the actions are already small. If a roof slab is connected to the wall, the joint requires separate consideration of continuity. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
A circular tank roof slab is connected structurally to the wall. Which approach is consistent with the IS 3370 guidance at the wall-roof junction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The free-top assumption is principally an aid for wall analysis and does not eliminate the physical wall-roof connection. IS 3370 states that continuity analysis should be carried out for a roof slab connected to the wall, allowing for wall-top rotation due to liquid pressure. Where such analysis is not performed, the stated simplified hinged assumption may be adopted at the junction. Nominal reinforcement is then required to control negative-moment cracking at that region. Therefore Option B is correct.
వివరణ:
Question 19
ప్రశ్న 19
When the base of a circular tank wall is monolithic with the floor slab, what restraint does IS 3370 recognize at the wall base?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A monolithic floor and cylindrical wall interact structurally at their junction. IS 3370 describes the floor slab as acting like a diaphragm at the base of the wall. This restrains radial displacement of the wall base to a negligible value. The degree of rotational restraint, however, still depends on the foundation and slab behaviour. Therefore Option B is correct.
వివరణ:
Question 20
ప్రశ్న 20
For a ground-supported circular tank resting on rock or hard soil with corrected SPT N-value greater than 30 or refusal, which base rotational idealization is permitted by IS 3370 Part 4 Section 3?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hard founding material provides substantial resistance to rotation of the wall-floor junction. IS 3370 states that where the foundation is rock or hard soil with corrected SPT N-value greater than 30 or refusal, wall-base rotation will be very small. The bottom may consequently be assumed fixed for the circular-wall analysis. This assumption differs from that recommended for soft foundation conditions. Therefore Option C is correct.
వివరణ:
Question 21
ప్రశ్న 21
For a circular tank on soft foundation soil with corrected SPT N-value less than 15, the fixed-base moment at a particular section away from the bottom edge is -20 kN·m/m and the corresponding hinged-base moment is -8 kN·m/m. Using the IS 3370 soft-soil interpolation rule, what design moment is obtained at that section?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For soft soil, the code permits the wall moment away from the bottom edge to be taken as the hinged result plus one-third of the algebraic difference between fixed and hinged results. The difference is -20 - (-8) = -12 kN·m/m. One-third of this difference is -4 kN·m/m. Adding it to the hinged value gives -8 - 4 = -12 kN·m/m. Therefore Option B is correct.
వివరణ:
Question 22
ప్రశ్న 22
For the same soft-foundation circular tank, if the fixed-base bottom-edge moment is -20 kN·m/m and the hinged-base bottom-edge moment is -8 kN·m/m, what bottom-edge moment is permitted by the stated IS 3370 soft-soil rule?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The bottom edge has a separate rule for the soft-soil case. IS 3370 permits the bottom-edge moment and shear to be taken as the average of the fixed and hinged end-restraint values. The average moment is [-20 + (-8)]/2 = -14 kN·m/m. This differs from the one-third interpolation used at other wall sections for the soft-soil condition. Therefore Option C is correct.
వివరణ:
Question 23
ప్రశ్న 23
For a ground-supported circular tank on foundation conditions intermediate between the hard-soil and soft-soil cases, take a fixed-base moment of -20 kN·m/m and a hinged-base moment of -8 kN·m/m. Which pair correctly gives the IS 3370 design moment away from the bottom edge and at the bottom edge respectively?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For foundation conditions between the explicitly hard and soft cases, the circular-wall base is treated as partially fixed. Away from the bottom edge, the design moment may be taken as the average of the fixed and hinged values, giving (-20 - 8)/2 = -14 kN·m/m. At the bottom edge, the fixed result is reduced by one-third of the difference in magnitude between fixed and hinged conditions. Thus the bottom-edge magnitude becomes 20 - (20 - 8)/3 = 16 kN·m/m, retaining the negative sign, so Option C is correct.
వివరణ:
Question 24
ప్రశ్న 24
Which reinforcement arrangement principally resists the membrane action in the main cylindrical region of an internally loaded circular RCC water tank?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Internal liquid pressure tends to expand a circular wall radially. This expansion produces circumferential or hoop tension around the cylindrical shell. Reinforcement running horizontally around the circumference is therefore the principal steel resisting this membrane tension. Vertical reinforcement remains necessary for bending, temperature, shrinkage, minimum reinforcement and other structural effects. Therefore Option B is correct.
వివరణ:
Question 25
ప్రశ్న 25
Why is circumferential reinforcement alone not sufficient for a fixed-base circular RCC tank wall?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Hoop reinforcement principally resists circumferential membrane tension caused by internal pressure. A fixed or partially fixed base restrains wall rotation and creates vertical bending moments near the wall-floor junction. Those moments produce vertical flexural tension that must be resisted by appropriately located vertical reinforcement. Crack-control and minimum-reinforcement requirements also require reinforcement in more than one direction. Therefore Option A is correct.
వివరణ:
Question 26
ప్రశ్న 26
Which statement most accurately compares the structural design of rectangular and circular RCC water-tank walls?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The geometry of a circular wall allows internal pressure to be resisted efficiently through circumferential membrane tension over much of the wall. Rectangular walls cannot develop the same continuous axisymmetric ring action and therefore depend substantially on plate bending and continuity with adjoining walls and slabs. Base and roof restraint can introduce additional bending in either tank form. Both types must also satisfy the specialized crack-control and liquid-tightness requirements applicable to liquid-retaining structures. Therefore Option B is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. Section 2 for rectangular tanks and Section 3 for circular tanks సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: B. It may develop two-way plate bending together with in-plane axial forces సమాధానం: B.
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Question 3 ప్రశ్న 3Answer: C. Loading distribution together with top and base restraint conditions and the relevant geometric ratios సమాధానం: C.
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Question 4 ప్రశ్న 4Answer: A. IS 3370 Part 4 Section 1 plate coefficients సమాధానం: A.
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Question 5 ప్రశ్న 5Answer: B. 40 kN/m² సమాధానం: B.
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Question 6 ప్రశ్న 6Answer: B. 80 kN/m at 1.33 m సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: C. 106.7 kN·m/m సమాధానం: C.
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Question 8 ప్రశ్న 8Answer: C. 28.8 kN·m/m సమాధానం: C.
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Question 9 ప్రశ్న 9Answer: B. 341 mm²/m సమాధానం: B.
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Question 10 ప్రశ్న 10Answer: B. Because IS 3370 serviceability, minimum-distributed-reinforcement and crack-control requirements must also be satisfied సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: B. T = pD/2 సమాధానం: B.
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Question 12 ప్రశ్న 12Answer: C. 120 kN/m సమాధానం: C.
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Question 13 ప్రశ్న 13Answer: C. 96 kN/m సమాధానం: C.
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Question 14 ప్రశ్న 14Answer: C. Inside diameter when an impermeable lining is used; otherwise inside diameter plus wall thickness సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: B. -12.8 kN·m/m సమాధానం: B.
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Question 16 ప్రశ్న 16Answer: B. A fixed base provides rotational restraint and therefore develops vertical bending moment near the base, whereas an ideal hinged base permits rotation and has different moment and ring-tension distributions సమాధానం: B.
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Question 17 ప్రశ్న 17Answer: B. The top may be assumed free from radial and rotational restraint సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: B. Carry out continuity analysis allowing for wall-top rotation, or use the stated hinged-junction simplification with appropriate nominal reinforcement where such analysis is absent సమాధానం: B.
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Question 19 ప్రశ్న 19Answer: B. The floor acts as a diaphragm and reduces radial displacement of the wall base to a negligible value సమాధానం: B.
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Question 20 ప్రశ్న 20Answer: C. Fixed at the bottom సమాధానం: C.
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Question 21 ప్రశ్న 21Answer: B. -12 kN·m/m సమాధానం: B.
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Question 22 ప్రశ్న 22Answer: C. -14 kN·m/m సమాధానం: C.
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Question 23 ప్రశ్న 23Answer: C. -14 kN·m/m and -16 kN·m/m సమాధానం: C.
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Question 24 ప్రశ్న 24Answer: B. Circumferential or horizontal ring reinforcement సమాధానం: B.
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Question 25 ప్రశ్న 25Answer: A. Because fixed-base restraint produces vertical bending moments that require vertical reinforcement in addition to hoop reinforcement సమాధానం: A.
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Question 26 ప్రశ్న 26Answer: B. Circular tanks can exploit circumferential membrane action, while rectangular tanks rely much more on plate bending and continuity between walls; both still require restraint and crack-control effects to be considered సమాధానం: B.