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Second Semester M.E. (Civil) (Structural Engg.) Degree Examination, Jan./Feb. 2014 (2K8 Scheme) SE 204/EQ 207(a) / CT 206 (b) : ADVANCED REINFORCED CONCRETE THEORY AND DESIGN (Common to Str/EQ/CT) (Structural Engineering and PSC – Also as Elective Paper to Earthquake Engg.) Time : 3 Hours

Max. Marks : 100

Note : 1) Answer any five full questions from Part A and two questions from Part B using Limit State Method. 2) Use of IS : 456-2000 and SP-16 Design Aids permitted. 3) Draw sketches and reinforcement detailing wherever necessary. PART – A Each full question carries 10 marks. 1. What are the different stages of behaviour of RC beam under progressively increasing bending moment from zero to failure ? Briefly explain each of them.

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2. Determine the limiting percentage of steel for an RC beam when M25 concrete and Fe 500 steel are adopted. Also determine the ultimate moment of resistance of a beam of rectangular cross section of width 250 mm and effective depth 450 mm when provided with 1.25 times tension steel required for the above limiting section. Adopt strain compatibility method if necessary. Effective cover to steel 50 mm. 10 3. What is “Pattern Loading” ? Explain the basis for different loading conditions stipulated in IS 456 for pattern loading ?

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4. Discuss the mechanism of shear transfer at crack location in a RC beam.

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5. a) Differentiate between equilibrium and compatibility torsion with an example each.

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b) Based on plastic theory show that the torsional strength at cracking of a rectangular concrete section is given by Tcr = τ tmax b2 (D – b/3) / 2, with usual notations.

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P.T.O.

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6. An interior panel measuring 7m × 6m in a flat slab has a drop of thickness 200 mm and slab of thickness 130 mm. Check for the adequacy of the thicknesses based on bending moment criterion if the total working load on slab is 9 kN/m2. 10 7. a) With respect to a short column supporting orthogonal beams of different depths at a junction, explain the following terms :

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i) Unsupported length ii) Minimum eccentricity iii) Lateral dimension. b) What are the functions performed by transverse steel in a column ? 8. Show the ductile detailing of a column in a beam column assembly.

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PART – B Each full question carries 25 marks. 9. A three span continuous beam ABCD has AB = CD = 6.0 m. and BC = 8.0 m. with extreme ends simply supported. The beam is subjected to service loads of super imposed dead and live loads of 15 kN/m. and 20 kN/m. respectively. The cross section of beam is 230 mm × 550 mm ( = D). a) Determine the maximum possible support moment and span moment in the beam.

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b) Redistributing the support moment by 10%, evaluate the maximum negative and positive bending moments in the beam.

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c) Design the support section for bending and shear using M25 concrete and Fe415 steel.

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10. a) The beam-slab system shown in Fig. 1 is subjected to superimposed dead and live load amounting to 12 kN/m2 (service load). Design in X direction all the panels of the slab using stipulated grade of concrete and Fe 415 steel. The structure is exposed to moderate conditions. 13

Fig. 1 Q. 10 (a) b) A short square column of side 450 mm is provided with longitudinal steel of 2% of c/s area at an effective cover of 50 mm. If fck and fy are 30 MPa and 500 MPa respectively, evaluate whether the section is safe or not when subjected to factored direct load of 750 kN acting at equal eccentricities of 40 mm about both major and minor axes of the cross section. 12 11. A fixed beam of effective span 6 m, width 300 mm and overall depth 600 mm is subjected to factored udl of 45 kN/m throughout the span. In addition, a factored twisting moment of 30 kNm / m is transferred from the supporting slab on to the beam. Design the beam using M25 grade concrete and Fe 415 grade steel. Effective cover to reinforcement is 50 mm. 25 _______________