JNTU
JNTU B.Tech III Year THEORY OF STRUCTURES Previous Question Paper (December - 2018 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
State the principle of superposition.
Answer
The principle of superposition states that for a linear elastic structure, the total displacement or stress at any point due to a system of loads is equal to the algebraic sum of the displacements or stresses caused by each load acting independently.
A hollow steel tube with internal diameter of 75mm is used to carry a tensile load of 350kN. If the stress is limited to 150MN/m2, determine the external diameter.
Answer
Given: P = 350 kN = 350,000 N, σ = 150 N/mm2, d = 75 mm. The area of a hollow tube is A = (π/4) * (D2 - d2). Since σ = P/A, then A = P/σ = 350,000 / 150 = 2333.33 mm2. Substituting: 2333.33 = (π/4) * (D2 - 752). Solving for D: D2 - 5625 = 2333.33 * 4 / π = 2971.3, so D2 = 8596.3. Thus, D = 92.72 mm.
Define modular ratio and state its formula.
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What is limiting depth of neutral axis and state the material properties on which it is dependent?
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Determine the development length required for 8mm diameter – Fe 415 Steel. Adopt M15 grade of concrete.
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If the theoretical steel needed is ‘As’ and if excess steel has been provided. What alterations can be done to the development length for the bars in tension?
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Explain classification of columns based on slenderness ratio.
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Distinguish between one way slab and two way slab.
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List out the conditions for checking the stability of a retaining wall.
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List out the assumptions of coulomb’s wedge theory for active earth pressure.
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PART - B
Derive the expressions for calculating radial pressure and hoop stress at any specified point in the section of a thick spherical shell.
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A steel tube of 300mm external diameter is to be shrunk onto another tube of 100mm internal diameter. The common diameter at the junction of two tubes is to be 180mm after shrinking-on. The original difference of diameters of the two tubes at the common junction is 0.1mm. Calculate the hoop stress in each tube after shrinking-on and also the radial pressure of the common surface. E = 2×105N/mm2.
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Design a doubly reinforced rectangular beam of 6.0 m effective span to carry a uniformly distributed load of 20kN/m and a live load of 30kN/m. Use Fe 415 steel and M20 grade of concrete.
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A rectangular beam 230 mm wide and 500 mm deep is reinforced with 3 bars of 25 mm diameter. Discuss the suitability of the beam to resist a maximum bending moment of 200kN-m?
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Write short notes on:
- Bond strength
- Bond failure Mechanisms
- Factors influencing bond strength
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A simply supported beam, 300 mm wide and 450mm effective depth carries a maximum shear force of 500kN. The beam is reinforced with 5 bars of 16 mm diameter and 2 legged 8 mm diameter vertical stirrups. Check the adequacy of the shear reinforcement. Use Fe415 steel and M 20 grade of concrete.
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Name three different types of reinforced concrete beams and their specific applications.
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Draw a cross-section of a singly reinforced rectangular beam and show the stress strain diagrams.
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Name four parameters which determine the effective widths of T and L beams.
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Design a one way slab, with a clear span of 4.5 m, simply supported on 230 mm thick masonry wall, and subjected to a live load of 3.5 kN/m2 using Fe 500 steel and concrete of grade M 20. Assume the slab is subjected to mild exposure.
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Design a circular tank with a flexible base for a capacity of 4,20,000 liters. The depth of water is to be 4.5m including a free board of 200mm. Also sketch the reinforcement details.
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Design the reinforcement in a column of size 450mm × 600mm, subjected to an axial load of 2500kN under service and dead loads. The column has an unsupported length of 3.5m and is braced against sideway in both the directions. Use M20 concrete and Fe 415 steel.
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