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Question 1
ప్రశ్న 1
A rectangular slab panel is supported on all four sides and has effective spans of 4.0 m in the short direction and 6.0 m in the long direction. Which structural action is generally appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The aspect ratio is ly/lx = 6.0/4.0 = 1.5. For a rectangular slab supported on four sides, an aspect ratio not exceeding 2 permits significant bending in both orthogonal directions. Such a panel is therefore treated as a two-way slab for ordinary design. Reinforcement is consequently required to resist flexural moments in both span directions. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
A four-side-supported rectangular slab has a longer effective span of 7.2 m and a shorter effective span of 3.2 m. Under the ordinary IS 456 aspect-ratio rule, how should it be treated?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The aspect ratio is 7.2/3.2 = 2.25. IS 456 Annex D states that when ly/lx is greater than 2, the slab is to be designed as spanning one way. Four-side support alone does not force a panel to behave as a design two-way slab when this ratio is exceeded. The dominant flexural action is then associated with the shorter span. Therefore Option C is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which statement best describes load sharing in an ordinary two-way slab subjected to uniformly distributed load?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A two-way slab carries load through flexural action in two orthogonal directions. The relative bending moments are influenced by the span ratio and by the degree of edge continuity or restraint. IS 456 coefficient methods represent this behavior through different moment coefficients rather than by a fixed equal split of load. Hence an assumed universal 50:50 division is not a general design rule. Therefore Option D is correct.
వివరణ:
Question 4
ప్రశ్న 4
For the Annex D coefficient method, which expression is used for the design moment per unit width in the short-span direction of a two-way slab?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
In Annex D, lx denotes the shorter span and ly denotes the longer span. The short-direction moment per unit width is expressed as Mx = αx w lx². The long-direction moment is similarly written as My = αy w lx², so the shorter-span length squared is used in both coefficient expressions. The coefficients account for the span ratio and relevant support condition. Therefore Option A is correct.
వివరణ:
Question 5
ప్రశ్న 5
Which pairing correctly distinguishes the two principal Annex D coefficient approaches for a slab supported on four sides?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Annex D separates restrained slabs from simply supported slabs that can lift at their corners. The restrained-slab provisions use Table 26 and distinguish different combinations of continuous and discontinuous edges. Table 27 is used when a simply supported slab lacks adequate provision to resist corner torsion and prevent the corners from lifting. The two tables therefore represent materially different boundary conditions and should not be interchanged casually. Therefore Option C is correct.
వివరణ:
Question 6
ప్రశ్న 6
An interior restrained two-way slab panel has ly/lx = 1.5. According to Table 26, which pair gives the short-span coefficients for negative moment at a continuous edge and positive moment at mid-span respectively?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For an interior panel, Table 26 provides separate short-span coefficients for support and mid-span moments. At ly/lx = 1.5, the short-span negative-moment coefficient is 0.053. The corresponding short-span positive-moment coefficient is 0.041. The values 0.032 and 0.024 are the long-span coefficients for the interior-panel case. Therefore Option B is correct.
వివరణ:
Question 7
ప్రశ్న 7
An interior restrained panel has lx = 4.0 m, ly/lx = 1.5 and a total factored design load w = 12 kN/m². Using Table 26, what are the positive mid-span moments Mx and My approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For an interior panel at ly/lx = 1.5, the positive coefficients are αx = 0.041 and αy = 0.024. The common load-span term is w lx² = 12 × 4² = 192 kN·m per metre width. Thus Mx = 0.041 × 192 = 7.872 kN·m/m. Similarly, My = 0.024 × 192 = 4.608 kN·m/m. Therefore Option D is correct.
వివరణ:
Question 8
ప్రశ్న 8
For the same interior restrained panel with lx = 4.0 m, ly/lx = 1.5 and w = 12 kN/m², what is the short-span negative design moment at a continuous edge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For the stated interior panel, the Table 26 short-span negative coefficient at ly/lx = 1.5 is 0.053. The load-span term is 12 × 4² = 192 kN·m per metre width. Multiplying gives Mx,negative = 0.053 × 192 = 10.176 kN·m/m. Rounded suitably, this is 10.18 kN·m/m. Therefore Option A is correct.
వివరణ:
Question 9
ప్రశ్న 9
A restrained two-way slab panel has all four edges discontinuous but has adequate corner torsion restraint against lifting. For ly/lx = 1.5, which Table 26 positive-moment coefficients apply?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Table 26 includes a specific case for a panel with four discontinuous edges when the restrained-slab corner provisions are applicable. At ly/lx = 1.5, its positive short-span coefficient is 0.089. The corresponding long-span coefficient for this case is 0.056. These values differ from the Table 27 coefficients because the corner behavior is different. Therefore Option C is correct.
వివరణ:
Question 10
ప్రశ్న 10
For the restrained four-discontinuous-edge panel in the previous question, take lx = 4.0 m and w = 12 kN/m². What positive design moments are obtained?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The relevant Table 26 coefficients are αx = 0.089 and αy = 0.056. The term w lx² is 12 × 4² = 192 kN·m per metre width. Hence Mx = 0.089 × 192 = 17.088 kN·m/m. The long-direction moment is My = 0.056 × 192 = 10.752 kN·m/m. Therefore Option B is correct.
వివరణ:
Question 11
ప్రశ్న 11
A slab is simply supported on all four sides and has no adequate provision to resist torsion at the corners or prevent corner lifting. If ly/lx = 1.5, which Table 27 coefficients apply?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Table 27 applies to the simply supported condition described in the question. For ly/lx = 1.5, the short-span coefficient αx is 0.104. The corresponding long-span coefficient αy is 0.046. These are not the same as the restrained four-discontinuous-edge values from Table 26 because corner torsional restraint changes the slab behavior. Therefore Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
For the simply supported unrestrained panel in the previous question, take lx = 4.0 m and w = 12 kN/m². What are the design moments Mx and My approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For ly/lx = 1.5, Table 27 gives αx = 0.104 and αy = 0.046. The common factor w lx² is 192 kN·m per metre width. The short-direction moment is therefore 0.104 × 192 = 19.968 kN·m/m. The long-direction moment is 0.046 × 192 = 8.832 kN·m/m. Therefore Option D is correct.
వివరణ:
Question 13
ప్రశ్న 13
Two panels have the same spans and factored load, with ly/lx = 1.5 and all four edges geometrically discontinuous. One has adequate corner torsion restraint against lifting and the other does not. Which statement is correct when the Annex D coefficient methods are used?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Boundary conditions influence two-way slab moments even when the panel dimensions and loads are unchanged. With adequate corner torsion restraint, the four-discontinuous-edge restrained case can be treated using Table 26. Without adequate torsion restraint and corner hold-down, the simply supported case is treated using Table 27. At ly/lx = 1.5, αx is 0.089 in the restrained Table 26 case but 0.104 in the unrestrained Table 27 case. Therefore Option B is correct.
వివరణ:
Question 14
ప్రశ్న 14
Under the restrained-slab provisions of Annex D, how is a panel divided into middle and edge strips in each direction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Annex D divides a restrained slab into a middle strip and two edge strips in each direction. The middle strip occupies three-quarters of the relevant panel width. Each edge strip occupies one-eighth of that width. The two edge strips together therefore account for the remaining one-quarter. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
How are the maximum moments obtained from the restrained-slab coefficient method applied to the strips?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The restrained-slab Annex D procedure assigns the calculated maximum moments to the middle strips. The code specifically states that no redistribution of these maximum moments is to be made within this strip procedure. Edge strips are instead subject to their stated minimum reinforcement and torsion requirements. Arbitrarily transferring moment away from the middle strip would therefore depart from the coefficient method. Therefore Option A is correct.
వివరణ:
Question 16
ప్రశ్న 16
At a restrained slab corner where both meeting edges are simply supported or discontinuous, what corner torsion reinforcement is required by Annex D?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Full corner torsion reinforcement is required where both edges meeting at the corner are simply supported under the restrained-slab provisions. It consists of reinforcement at both the top and bottom faces. At each face, bars are placed parallel to both sides, producing four reinforcement layers in total. The area in each layer is three-quarters of the area required for the maximum mid-span moment, and the bars extend at least one-fifth of the shorter span from the edges. Therefore Option D is correct.
వివరణ:
Question 17
ప్రశ్న 17
A restrained two-way slab has a shorter span lx = 4.0 m. At a corner requiring full torsion reinforcement, what minimum distance should the corner torsion bars extend from each relevant edge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Full corner torsion reinforcement must extend from the edges by at least one-fifth of the shorter span. Here the shorter span is 4.0 m. One-fifth of 4.0 m is 0.80 m. The extension requirement is related to lx rather than the longer span. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
If the reinforcement area required for the maximum mid-span moment of a restrained slab is 600 mm²/m, what area should be provided in each of the four layers of full corner torsion reinforcement?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For full corner torsion reinforcement, each of the four layers is three-quarters of the area required for the maximum mid-span moment. The stated mid-span reinforcement area is 600 mm²/m. Three-quarters of 600 is 450 mm²/m. This amount is provided in each individual top-or-bottom directional layer at the corner. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
At a slab corner bounded by two edges of which only one is continuous, what corner torsion reinforcement is required under Annex D?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Annex D reduces the torsion reinforcement when only one of the two edges meeting at a corner is continuous. The required amount is one-half of the full torsion reinforcement specified for a corner where both meeting edges are discontinuous. Thus, if a full layer would be 0.75 times the maximum mid-span steel area, the half-torsion layer is 0.375 times that area. The same corner-zone concept is retained but with the reduced steel quantity. Therefore Option A is correct.
వివరణ:
Question 20
ప్రశ్న 20
At a corner bounded by edges over both of which the slab is continuous, what does Annex D require for corner torsion reinforcement?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
When both edges meeting at a corner are continuous, Annex D does not require the special corner torsion reinforcement described for discontinuous corners. Continuity provides a different restraint condition from a corner bounded by two simply supported edges. This rule should not be confused with ordinary flexural reinforcement over continuous supports, which may still be necessary. The statement concerns the special corner torsion reinforcement only. Therefore Option D is correct.
వివరణ:
Question 21
ప్రశ్న 21
For a restrained slab middle strip, which statement correctly describes the extension of positive mid-span tension reinforcement toward an edge?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Annex D gives specific curtailment limits for positive mid-span reinforcement in restrained slab middle strips. The reinforcement is placed in the lower part of the slab because the mid-span bending is positive. It is extended to within 0.25l of a continuous edge. At a discontinuous edge, it extends closer to the support, namely to within 0.15l. Therefore Option B is correct.
వివరణ:
Question 22
ప్రశ్న 22
Which detailing rule applies to tension reinforcement over a continuous edge of the middle strip of a restrained two-way slab?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Continuity produces negative bending near a continuous edge, so tension reinforcement is needed in the upper part of the slab. Annex D requires the support tension reinforcement to extend at least 0.15l from the support. It further requires at least 50 percent of that reinforcement to extend to a distance of 0.3l. This detailing provides reinforcement through the region in which the negative moment persists. Therefore Option C is correct.
వివరణ:
Question 23
ప్రశ్న 23
At a discontinuous edge of a restrained slab, negative moment may arise because of partial fixity. What general reinforcement provision does Annex D state will usually be sufficient?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A nominal negative moment can develop at a nominally discontinuous edge because actual rotational restraint may not be exactly zero. Annex D recognizes this possible partial fixity. As a general provision, top tension reinforcement equal to 50 percent of that provided at mid-span is stated to be sufficient. This reinforcement extends 0.1l into the span from the edge. Therefore Option A is correct.
వివరణ:
Question 24
ప్రశ్న 24
For a simply supported two-way slab designed using the Annex D simply supported provisions, how should the mid-span tension reinforcement be extended toward the supports?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The simply supported slab provisions include a specific rule for anchoring and curtailing the mid-span tension reinforcement. At least half of that reinforcement is to extend to the supports. The remaining half is permitted to terminate earlier. Its termination point should be within 0.1 of the appropriate span from the support, using lx or ly according to the bar direction. Therefore Option D is correct.
వివరణ:
Question 25
ప్రశ్న 25
A 160 mm thick M25 two-way slab with Fe500 reinforcement is designed for the restrained four-discontinuous-edge case with lx = 4.0 m, ly/lx = 1.5 and w = 12 kN/m². Assume d = 140 mm for both directional strength checks. Using the moments Mx = 17.088 kN·m/m and My = 10.752 kN·m/m, which approximate design steel areas govern after checking the 0.12 percent minimum slab reinforcement?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For a one-metre strip, the singly reinforced Limit State equations with M25 concrete, Fe500 steel and d = 140 mm give about 293 mm²/m for Mx = 17.088 kN·m/m. The same calculation for My = 10.752 kN·m/m gives about 181 mm²/m. Minimum reinforcement with high-strength deformed bars is 0.12 percent of the gross slab area, which for 1000 × 160 mm is 192 mm²/m. Thus the calculated short-direction requirement of about 293 mm²/m governs there, while the long-direction requirement is raised to the minimum of 192 mm²/m. Therefore Option B is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
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Question 1 ప్రశ్న 1Answer: B. Two-way slab action because ly/lx = 1.5, which does not exceed 2 సమాధానం: B.
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Question 2 ప్రశ్న 2Answer: C. As a one-way slab because ly/lx is greater than 2 సమాధానం: C.
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Question 3 ప్రశ్న 3Answer: D. Moments develop in both directions, and their magnitudes depend on panel geometry and support conditions rather than a universal 50:50 split సమాధానం: D.
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Question 4 ప్రశ్న 4Answer: A. Mx = αx w lx² సమాధానం: A.
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Question 5 ప్రశ్న 5Answer: C. Table 26 is used for restrained panels with corner lifting prevented and appropriate edge conditions, while Table 27 applies to simply supported slabs without adequate corner torsion restraint to prevent lifting సమాధానం: C.
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Question 6 ప్రశ్న 6Answer: B. 0.053 and 0.041 సమాధానం: B.
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Question 7 ప్రశ్న 7Answer: D. Mx = 7.87 kN·m/m and My = 4.61 kN·m/m సమాధానం: D.
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Question 8 ప్రశ్న 8Answer: A. 10.18 kN·m/m సమాధానం: A.
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Question 9 ప్రశ్న 9Answer: C. αx = 0.089 and αy = 0.056 సమాధానం: C.
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Question 10 ప్రశ్న 10Answer: B. Mx = 17.09 kN·m/m and My = 10.75 kN·m/m సమాధానం: B.
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Question 11 ప్రశ్న 11Answer: A. αx = 0.104 and αy = 0.046 సమాధానం: A.
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Question 12 ప్రశ్న 12Answer: D. Mx = 19.97 kN·m/m and My = 8.83 kN·m/m సమాధానం: D.
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Question 13 ప్రశ్న 13Answer: B. The unrestrained simply supported panel uses Table 27 and can have a larger short-span positive coefficient than the torsion-restrained Table 26 panel సమాధానం: B.
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Question 14 ప్రశ్న 14Answer: C. Middle strip three-quarters of the width and each edge strip one-eighth సమాధానం: C.
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Question 15 ప్రశ్న 15Answer: A. They apply to the middle strips, and no redistribution of those maximum moments is to be made సమాధానం: A.
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Question 16 ప్రశ్న 16Answer: D. Top and bottom reinforcement in both directions, with each of four layers having three-quarters of the area required for the maximum mid-span moment and extending at least lx/5 from the edges సమాధానం: D.
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Question 17 ప్రశ్న 17Answer: B. 0.80 m సమాధానం: B.
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Question 18 ప్రశ్న 18Answer: C. 450 mm²/m సమాధానం: C.
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Question 19 ప్రశ్న 19Answer: A. Half of the full corner torsion reinforcement specified for a corner with both meeting edges discontinuous సమాధానం: A.
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Question 20 ప్రశ్న 20Answer: D. No corner torsion reinforcement is required by this Annex D rule సమాధానం: D.
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Question 21 ప్రశ్న 21Answer: B. It should extend in the lower part of the slab to within 0.25l of a continuous edge or 0.15l of a discontinuous edge సమాధానం: B.
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Question 22 ప్రశ్న 22Answer: C. The upper tension reinforcement should extend at least 0.15l from the support, with at least 50 percent extending to 0.3l సమాధానం: C.
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Question 23 ప్రశ్న 23Answer: A. Top tension reinforcement equal to 50 percent of the mid-span reinforcement, extending 0.1l into the span సమాధానం: A.
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Question 24 ప్రశ్న 24Answer: D. At least 50 percent should extend to the supports, and the remaining 50 percent should extend to within 0.1lx or 0.1ly of the support as appropriate సమాధానం: D.
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Question 25 ప్రశ్న 25Answer: B. 293 mm²/m in the short direction and 192 mm²/m in the long direction సమాధానం: B.