Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
According to IS 456 terminology, which statement correctly identifies a column or strut?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 456 defines a column or strut in terms of effective length and lateral dimension rather than merely by its vertical orientation. Its effective length must exceed three times its least lateral dimension. A very short compression member below this limit falls within the pedestal concept rather than the ordinary column definition. The definition also does not require the applied load to be perfectly concentric. Therefore Option B is correct.
వివరణ:
Question 2
ప్రశ్న 2
For a rectangular reinforced concrete compression member with effective lengths lex and ley and corresponding lateral dimensions D and b, when may the member be classified as a short column?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Column slenderness has to be checked about both relevant axes. IS 456 treats the compression member as short only when both effective-length ratios are less than 12. Satisfying the limit about only one axis is not sufficient. If either relevant ratio reaches the slender range, slender-column effects have to be considered in that direction. Therefore Option D is correct.
వివరణ:
Question 3
ప్రశ్న 3
Which statement correctly describes a reinforced concrete pedestal under IS 456?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
A pedestal is distinguished from an ordinary column primarily by its very small effective length relative to its lateral dimension. IS 456 describes a pedestal as a compression member whose effective length does not exceed three times its least lateral dimension. The definition is not based on whether the member is reinforced or unreinforced. It also has nothing to do with the slenderness ratio exceeding 12. Therefore Option A is correct.
వివరణ:
Question 4
ప్రశ్న 4
When a more exact structural analysis is not available, how may the effective length of a reinforced concrete column in a framed structure be assessed under IS 456?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Effective length represents the influence of restraint and possible lateral displacement on column buckling behavior. It is therefore not necessarily identical to the unsupported or clear storey length. IS 456 refers to Annex E for assessment of effective length when a more exact analysis is not available. The relevant end rotational restraint and whether sway is prevented are important in this assessment. Therefore Option C is correct.
వివరణ:
Question 5
ప్రశ్న 5
A 300 mm × 450 mm rectangular column has an effective length of 3.60 m about the axis for which the corresponding lateral dimension is 450 mm and 3.30 m about the axis for which the corresponding lateral dimension is 300 mm. How should it be classified?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The first slenderness ratio is 3600/450 = 8. The second ratio is 3300/300 = 11. Both values are less than the limiting value of 12 used for classification as a short compression member. The absolute length of the member by itself does not determine whether it is short or slender. Therefore Option B is correct.
వివరణ:
Question 6
ప్రశ్న 6
A 300 mm × 450 mm column has one effective-length ratio equal to 9 and the other equal to 13. Which classification is appropriate?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Both directional slenderness checks must satisfy the short-column criterion. In this case one ratio is 9, which is within the short-column range. The other ratio is 13 and therefore exceeds the limit of 12. The member consequently requires treatment as a slender compression member in the direction associated with the larger ratio. Therefore Option D is correct.
వివరణ:
Question 7
ప్రశ్న 7
What expression gives the minimum eccentricity to be considered for an RCC column in a particular direction, where l is the unsupported length and D is the relevant lateral dimension?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Perfect concentric loading is not assumed for practical reinforced concrete column design. IS 456 introduces a minimum eccentricity to account for unavoidable imperfections and construction tolerances. The prescribed expression is l/500 + D/30 in the direction under consideration. The resulting value is also subject to an absolute minimum of 20 mm. Therefore Option B is correct.
వివరణ:
Question 8
ప్రశ్న 8
A column has an unsupported length of 3.60 m and a lateral dimension of 450 mm in the direction being checked. What minimum eccentricity should be considered in that direction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The calculated eccentricity is l/500 + D/30. Substitution gives 3600/500 + 450/30 = 7.2 + 15 = 22.2 mm. This value is greater than the absolute minimum requirement of 20 mm. Hence the calculated 22.2 mm controls the design check in this direction. Therefore Option C is correct.
వివరణ:
Question 9
ప్రశ్న 9
A 300 mm square short column has an unsupported length of 3.0 m. Its minimum eccentricity in a direction is governed by the 20 mm absolute minimum. Can the simplified short axially loaded column equation of IS 456 Clause 39.3 be used directly in that direction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The simplified axial-capacity expression is not permitted solely because a member is geometrically short. Its minimum eccentricity must also not exceed 0.05 times the relevant lateral dimension. For a 300 mm dimension, this limiting eccentricity is 0.05 × 300 = 15 mm. The applicable minimum eccentricity of 20 mm exceeds 15 mm. Therefore the simplified Clause 39.3 expression cannot be used directly in this direction and Option C is correct.
వివరణ:
Question 10
ప్రశ్న 10
A short column has an unsupported length of 3.60 m and a relevant lateral dimension of 450 mm. The minimum eccentricity is 22.2 mm. Which statement is correct regarding use of the simplified axial-capacity equation in that direction?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Clause 39.3 permits the simplified short-axial-column expression when the prescribed minimum eccentricity does not exceed 0.05 times the relevant lateral dimension. Here that limit is 0.05 × 450 = 22.5 mm. The calculated minimum eccentricity is 22.2 mm, which is slightly smaller than the limit. Therefore this eccentricity condition is satisfied in the direction being considered. Hence Option A is correct.
వివరణ:
Question 11
ప్రశ్న 11
For a short axially loaded tied RCC column satisfying the minimum-eccentricity condition of Clause 39.3, which expression gives its design axial strength?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 456 provides a simplified Limit State expression for qualifying short axially loaded compression members. The concrete contribution is taken as 0.4fckAc. The longitudinal steel contribution is taken as 0.67fyAsc. Here Ac is the area of concrete excluding the longitudinal reinforcement area, while Asc is the longitudinal steel area. Therefore Option C is correct.
వివరణ:
Question 12
ప్రశ్న 12
A 400 mm × 400 mm tied short column uses M25 concrete and four 20 mm diameter Fe415 longitudinal bars. Assuming the Clause 39.3 eccentricity condition is satisfied, what is its design axial load capacity approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The steel area is 4 × π(20²)/4 = about 1256.6 mm². The concrete area is 160000 - 1256.6 = about 158743.4 mm². The concrete contribution is 0.4 × 25 × 158743.4 = about 1587.4 kN, while the steel contribution is 0.67 × 415 × 1256.6 = about 349.4 kN. Their sum is approximately 1936.8 kN, so Option B is correct.
వివరణ:
Question 13
ప్రశ్న 13
A 350 mm × 350 mm tied short column contains eight 20 mm diameter Fe500 longitudinal bars and is made with M30 concrete. Assuming the Clause 39.3 conditions are satisfied, what is its design axial capacity approximately?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Eight 20 mm bars provide Asc = 8 × π(20²)/4 = about 2513.3 mm². The gross section is 350 × 350 = 122500 mm², so Ac is approximately 119986.7 mm². The concrete contribution is 0.4 × 30 × 119986.7 = about 1439.8 kN. The steel contribution is 0.67 × 500 × 2513.3 = about 842.0 kN, giving a total of approximately 2281.8 kN. Therefore Option C is correct.
వివరణ:
Question 14
ప్రశ్న 14
A 400 mm × 400 mm tied short column of M25 concrete and Fe415 steel is required to carry a factored axial load of 2200 kN. Assuming the Clause 39.3 equation is applicable, what longitudinal steel area is required approximately from the strength equation?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
For the column, Ag = 160000 mm² and Ac = Ag - Asc. Substituting in Pu = 0.4fckAc + 0.67fyAsc gives 2200000 = 10(160000 - Asc) + 278.05Asc. Solving yields Asc of approximately 2238 mm². This is also greater than the ordinary 0.8 percent minimum steel area of 1280 mm². Therefore approximately 2240 mm² is required and Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
In applying Pu = 0.4fckAc + 0.67fyAsc to a reinforced concrete column, how should Ac be interpreted?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The simplified equation separates the contributions of concrete and longitudinal reinforcement. Because the steel contribution is included independently as 0.67fyAsc, the same physical area must not also be counted as concrete. Accordingly, Ac represents the area of concrete in the section. It is obtained by subtracting the longitudinal steel area from the gross sectional area. Therefore Option C is correct.
వివరణ:
Question 16
ప్రశ్న 16
What maximum compressive strain in concrete is assumed by IS 456 for pure axial compression in Limit State design?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The Limit State assumptions for compression members specify a particular strain for concrete under axial compression. The maximum compressive strain is taken as 0.002 for the pure axial-compression condition. This value differs from the familiar 0.0035 extreme-fibre strain associated with flexural compression situations. The distinction is important when interpreting column strength assumptions. Therefore Option B is correct.
వివరణ:
Question 17
ప్రశ్న 17
A rectangular column is 350 mm × 450 mm. What is the ordinary minimum longitudinal reinforcement area based on the gross cross-sectional area?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 456 generally requires longitudinal reinforcement in a column to be at least 0.8 percent of the gross cross-sectional area. The gross area is 350 × 450 = 157500 mm². Taking 0.8 percent gives 0.008 × 157500 = 1260 mm². This is a detailing minimum and a larger steel area may be required by strength design. Therefore Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
For the same 350 mm × 450 mm column, what is the code upper limit of longitudinal reinforcement based on 6 percent of the gross area?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The gross area of the column is 157500 mm². Six percent of this area is 0.06 × 157500 = 9450 mm². IS 456 gives 6 percent as the general upper limit for longitudinal reinforcement in a column. In practice, lower percentages are often preferred because very heavy reinforcement causes placement and compaction difficulties, and congestion at laps also requires attention. Therefore Option C is correct.
వివరణ:
Question 19
ప్రశ్న 19
Which statement correctly gives the minimum number of longitudinal bars in ordinary RCC columns?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The code prescribes minimum bar counts to ensure a suitable reinforcement arrangement around a column section. A rectangular column requires at least four longitudinal bars. A circular column requires at least six longitudinal bars. These are minimum numbers and more bars may be necessary for strength, spacing, or detailing reasons. Therefore Option C is correct.
వివరణ:
Question 20
ప్రశ్న 20
What is the minimum permitted diameter of longitudinal reinforcement bars in an ordinary RCC column under IS 456?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
IS 456 places a specific minimum diameter on longitudinal reinforcement in columns. The longitudinal bars are not to be less than 12 mm in diameter. This requirement is separate from the minimum total longitudinal reinforcement percentage. A design must therefore satisfy both the required steel area and the individual-bar diameter provision. Therefore Option C is correct.
వివరణ:
Question 21
ప్రశ్న 21
What is the maximum spacing of longitudinal reinforcement measured along the periphery of an RCC column?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Longitudinal bars must be suitably distributed around the perimeter rather than being concentrated only at widely separated locations. IS 456 limits the spacing of longitudinal bars measured along the periphery of a column to 300 mm. Additional longitudinal bars may therefore become necessary in large column sections even when the total steel area is already adequate. This is primarily a detailing and reinforcement-distribution requirement. Therefore Option C is correct.
వివరణ:
Question 22
ప్రశ్న 22
Which expression correctly states the ordinary maximum pitch of lateral ties in an RCC compression member?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The pitch of lateral ties has to satisfy three separate upper limits. These are the least lateral dimension of the compression member, sixteen times the smallest diameter of the longitudinal bar being tied, and 300 mm. Since all three limits must be satisfied, the smallest numerical value governs. The provision ensures sufficiently frequent lateral support against buckling of the longitudinal bars. Therefore Option B is correct.
వివరణ:
Question 23
ప్రశ్న 23
A 300 mm × 450 mm tied column uses 16 mm diameter longitudinal bars. What is the maximum ordinary pitch of the lateral ties?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The three pitch limits are the least lateral dimension, sixteen times the smallest longitudinal-bar diameter, and 300 mm. They evaluate to 300 mm, 16 × 16 = 256 mm, and 300 mm respectively. The least of these values is 256 mm. Hence the lateral-tie pitch must not exceed 256 mm under this ordinary provision. Therefore Option B is correct.
వివరణ:
Question 24
ప్రశ్న 24
Which rule governs the minimum diameter of ordinary polygonal links or lateral ties in an RCC column?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
The tie diameter is related to the size of the longitudinal reinforcement that it laterally restrains. IS 456 requires the diameter of polygonal links or lateral ties to be at least one-fourth of the diameter of the largest longitudinal bar. An absolute minimum of 6 mm also applies. The larger value obtained from these two requirements controls. Therefore Option B is correct.
వివరణ:
Question 25
ప్రశ్న 25
A tied RCC column uses longitudinal bars whose largest diameter is 32 mm. What minimum lateral-tie diameter follows from the ordinary IS 456 rule?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
One-fourth of the largest longitudinal-bar diameter is 32/4 = 8 mm. The absolute minimum tie diameter is 6 mm. The tie must satisfy both requirements, so the larger value governs. Consequently a minimum diameter of 8 mm is required for the ties in this case. Therefore Option B is correct.
వివరణ:
Question 26
ప్రశ్న 26
What is the fundamental structural purpose of lateral ties in a tied reinforced concrete column?
Select an option first. || ముందుగా ఒక సమాధానాన్ని ఎంచుకోండి.
Explanation:
Longitudinal bars in a compression member are themselves susceptible to lateral instability between restraint points. Lateral ties provide effective restraint against this buckling tendency. They also help maintain the intended position and integrity of the longitudinal reinforcement cage during construction and loading. Their role is therefore complementary to, rather than a replacement for, longitudinal reinforcement. Therefore Option C is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
-
Question 1 ప్రశ్న 1Answer: B. A compression member whose effective length exceeds three times its least lateral dimension సమాధానం: B.
-
Question 2 ప్రశ్న 2Answer: D. When both lex/D and ley/b are less than 12 సమాధానం: D.
-
Question 3 ప్రశ్న 3Answer: A. It is a compression member whose effective length does not exceed three times its least lateral dimension సమాధానం: A.
-
Question 4 ప్రశ్న 4Answer: C. It may be assessed using the effective-length provisions of Annex E according to end restraint and sway conditions సమాధానం: C.
-
Question 5 ప్రశ్న 5Answer: B. Short because the two slenderness ratios are 8 and 11 సమాధానం: B.
-
Question 6 ప్రశ్న 6Answer: D. Slender because one of the two relevant slenderness ratios exceeds the short-column limit సమాధానం: D.
-
Question 7 ప్రశ్న 7Answer: B. l/500 + D/30, subject to a minimum of 20 mm సమాధానం: B.
-
Question 8 ప్రశ్న 8Answer: C. 22.2 mm సమాధానం: C.
-
Question 9 ప్రశ్న 9Answer: C. No, because 20 mm exceeds 0.05 × 300 = 15 mm సమాధానం: C.
-
Question 10 ప్రశ్న 10Answer: A. It may be used because 22.2 mm does not exceed 0.05 × 450 = 22.5 mm సమాధానం: A.
-
Question 11 ప్రశ్న 11Answer: C. Pu = 0.4 fck Ac + 0.67 fy Asc సమాధానం: C.
-
Question 12 ప్రశ్న 12Answer: B. 1,937 kN సమాధానం: B.
-
Question 13 ప్రశ్న 13Answer: C. 2,282 kN సమాధానం: C.
-
Question 14 ప్రశ్న 14Answer: C. 2240 mm² సమాధానం: C.
-
Question 15 ప్రశ్న 15Answer: C. As the concrete area equal to the gross section minus the longitudinal reinforcement area సమాధానం: C.
-
Question 16 ప్రశ్న 16Answer: B. 0.002 సమాధానం: B.
-
Question 17 ప్రశ్న 17Answer: B. 1260 mm² సమాధానం: B.
-
Question 18 ప్రశ్న 18Answer: C. 9450 mm² సమాధానం: C.
-
Question 19 ప్రశ్న 19Answer: C. Four bars in a rectangular column and six bars in a circular column సమాధానం: C.
-
Question 20 ప్రశ్న 20Answer: C. 12 mm సమాధానం: C.
-
Question 21 ప్రశ్న 21Answer: C. 300 mm సమాధానం: C.
-
Question 22 ప్రశ్న 22Answer: B. The least of the least lateral dimension, 16 times the smallest longitudinal-bar diameter and 300 mm సమాధానం: B.
-
Question 23 ప్రశ్న 23Answer: B. 256 mm సమాధానం: B.
-
Question 24 ప్రశ్న 24Answer: B. Not less than one-fourth of the largest longitudinal-bar diameter and not less than 6 mm సమాధానం: B.
-
Question 25 ప్రశ్న 25Answer: B. 8 mm సమాధానం: B.
-
Question 26 ప్రశ్న 26Answer: C. To provide effective lateral support to longitudinal bars against buckling and maintain the reinforcement cage సమాధానం: C.