JNTU B.Tech III THEORY OF STRUCTURES Previous Question Paper (April - 2018 - R15)

Which shell is more efficient in resisting pressure – the cylindrical or the spherical shell? Why?

Distinguish between circumferential stress and longitudinal stress in a cylindrical shell when subjected to an internal pressure.

How does the shear span influence the mode of shear failure?

Under what circumstances are doubly reinforced beams resorted to?

The provision of a minimum stirrup reinforcement is mandatory in all reinforced concrete beams. Why?

Define ‘development length’. What is its significance?

What is the function of providing distribution steel in a slab?

What are the types of two-way slabs?

What is meant by slenderness ratio of a compression member?

What is the purpose of shear key and its action?

Explain the difference in the behaviour of thin and thick cylindrical shells.

Show that in the case of a thin cylindrical shell subjected to an internal fluid pressure, the tendency to burst lengthwise is twice as great as in a transverse section.

Derive a formula for the hoop stress in a thin spherical shell subjected to an internal pressure.

Write the relations for the hoop stress in a thick spherical shell.

What are the assumptions in the theory of design of doubly reinforced beam regarding the role of compression steel?

Determine the ultimate moment capacity of a doubly reinforced beam with b=350 mm, dꞌ=60 mm, d=550 mm, Asc=1690 mm², Ast=4310 mm², fck=30 MPa and fy=415 MPa.

Explain the necessity for specifying the maximum and minimum tension steel in reinforced beams.

Explain the terms ‘balanced’, ‘over reinforced’ and ‘under reinforced’ sections in bending. Explain which of these should be recommended in design. How is this ensured in design of beams according to IS 456?

Reinforced concrete slabs are generally safe in shear and do not require shear reinforcement. Why?

An RCC beam 250 mm × 500 mm has a clear span of 5.5m. The beam has 2-20mm diameter bars going into the support. Factored shear force is 140 kN. Check for the development length if concrete mix and steel to be used in construction are of grades M25 and Fe415 respectively.

An RCC beam 250 mm × 400 mm has a clear span of 4m and carrying uniformly distributed load of 16 kN/m. The beam has 4-22mm diameter bars. Factored shear force is 140 kN. Design the shear reinforcement. Use Concrete of M20 grade and plain mild steel bars.

What is a ‘theoretical bar cut-off point’? Why does the IS code disallow curtailment of flexural tension reinforcement at this point?

Explain the concept underlying the Rankine-Grashoff theory as applied to uniformly loaded and simply supported rectangular two-way slabs.

Design a reinforced concrete spiral column of 390mm diameter subjected to an axial factored load of 1750 kN. The column is braced against the side sway and has unsupported length of 3.3 m. The concrete mix and steel to be used in construction are of grades M25 and Fe415 respectively.

What are the assumptions underlying the Code moment coefficients for the two-way ‘restrained’ slabs?

Explain briefly the IS code method of designing the two way slab.

Explain the conditions for stability of retaining walls.

Mention various types of foundations and their suitability.

List the design steps for Isolated rectangular footing.

Using Janssen’s theory, derive an expression for horizontal pressure at any depth ‘h’ below the top in a silo. Also derive the expression for total vertical load of the grain transferred to the walls.