Design and Construction of Concrete Structures

1

Total No. of Pages: 2

Register Number: 6991

Name of the Candidate:

P.G.DIPLOMA EXAMINATION - 2012

(DESIGN AND CONSTRUCTION OF CONCRETE STRUCTURES)

(paper –II)

120. THEORY OF CONCRETE STRUCTURES

May) Maximum: 100 Marks (Time: 3 Hours

Answer ALL questions(5 × 20= 100)

UNIT-I

/ a)What are concrete elements? Explain the terms strength, serviceability, ductility criteria of concrete structures.
b)Discuss FTP and IS code provisions for ductility and flexure of concrete structures.
(OR)
/ a)Explain the effect of segregation and bleeding of concrete.
b)Mention the factors on which the strength of concrete depends and explain them in detail.
UNIT-II
/ A reinforced concrete 220mm wide and 410mm effective depth is subjected to a shear force of 125kN at the supports. The tensile reinforcement at the support is 0.5%. Determine the spacing of 12mm diameter and 2 legged stirrups to resist the shearing stress at supports for M20 grade concrete.Use Fe415 bars. Also determine the minimum shear reinforcement at the mid span of the beam.
(OR)
/ a)Explain briefly “Working stress Method” of designing concrete structures under flexure, shear and torsion.
b)Explain Ultimate load theory.
UNIT-III
/ a)Define the following:
(i)Characteristic strength of materials
(ii)Characteristic loads
(iii)Partial safety factors
(iv)Cracking and deflection
b)Why limit state design is considered more rational than working stress design?
(OR)
/ a)Explain limit state of strength and serviceability criteria.
b)Determine the moment of resistance of a singly reinforced concrete beam section of 225mm width and 425mm effective depth, reinforced with 8 mild steel bars of 16mm diameter. Use M20 grade concrete.Adopt IS code limit state design.
UNIT-IV
/ a)Write and explain the provision for moment redistribution as per IS code.
b)A three span continuous beam of uniform section is subjected to uniformly distributed load of 30kN/m throughout the span. Each span =3.8m.The two extreme ends are simply supported. Determine the collapse moment of the beam using Cambridge method.
(OR)
/ a)Briefly explain Baker’s method of analysis of indeterminate structures in detail.
b)Differentiate determinate and indeterminate structures and also explain moment curvature relationship.
UNIT-V
/ a)Draw yield line patterns for slabs of various shapes and different supports. Explain the methods of analysis of slabs briefly.
b)Describe Hillerborg’s strip method.
(OR)
/ Design a circular slab 6m diameter fixed all around the edges subjected to live load of 5kN/m2. Take load factors are 1.5 and 2.2 for dead load and live load respectively. Use M25 concrete rebars of grade Fe500.

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