1. a) Distinguish between balanced, over-reinforced and under-reinforced sections in (5) limit state design. Which of these should be recommended in design?
b) Find the moment of resistance of a singly reinforced concrete beam of 200 mm (10) width and 400 mm effective depth, reinforced with 4 bars of 16 mm diameter of Fe415 steel. Take M20 concrete. Redesign the beam if necessary.
2. a) With neat sketch explain the stress block parameters used in the design of singly (5) reinforced concrete beam as per limit state method.
b) Design the shear reinforcement for a beam with b= 350 mm, d= 550 mm, Vu= (10) 125 kN, fck= 25 N/mm2, fy= 415 N/mm2. Percentage of steel is 1.67 percent.
3.a) A simply supported beam, 300 mm wide and 600 mm effective depth carries a (10) uniformly distributed load of 74 kN/m including its own weight over an effective span of 6 m. The reinforcement consists of 5 bars of 25 mm diameter. Out of these, two bars can be safely bent up at 1 m distance from the support. Design shear reinforcement for the beam.
b) Define development length and derive an expression for development length. (5)
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4 a) What are the situations that demand double reinforcement in beams? Compare (5) the stress strain distributions in singly reinforced and doubly reinforced beams.
b) Determine the moment of resistance of beam having width b of 350 mm, depth of (10) 900 mm with a cover of 50 mm. Beam is reinforced with 5 tension reinforcements of 20 mm HYSD bars (Fe 415) and 2 compression reinforcements of 20 mm Fe 415 steel. Grade of concrete is M15.
5.Design a simply supported RCC slab for a roof of a hall 4 m × 10 m (inside (15) dimensions) with 230 mm walls all around. Assume a live load of 4 kN/m2 and finish 1 kN/m2. Use M 25 concrete and Fe 415 steel.
6.a) Differentiate between one way slab and two way slab. (5)
b) A T-beam has the following data: width of flange= 750 mm, Breadth of beam= (10) 250 mm, Effective depth= 500 mm, Thickness of flange= 90 mm. Determine the limiting moment of resistance of the beam. Use M20 concrete and Fe415 steel.
7.
a) Design a reinforced concrete slab 6.3 × 4.5 m simply supported on all the four (15) sides. It has to carry a characteristic live load of 10 kN/m2 in addition to its dead weight. Assume M25 concrete and Fe 415 steel; also assume mild exposure conditions.
b) Explain the procedure for estimation of flexural crack width in reinforced (5) concrete members as per IS456.
8.
a) Design and detail a dog-legged stair for a building in which the vertical distance (15) between the floors is 3.6 m. The stair hall measures 2.5 m × 5 m. The live load may be taken as 2500 N/m2. Assume that stair is supported at outer edges. Use M20 concrete and Fe415 steel.
b) Sketch typical reinforcement detail in tread-riser type stairs. (5)
9.
a) Design a circular short column to carry an axial load of 1000 kN using helical (12) reinforcement. Use M20 concrete and Fe 415 steel.
b)How does one (a) check for deflections of two way slabs, and (b) control crack (8) width in two way slabs?
1 a) Why are over reinforced sections not used in practice? ( 5)
b) A concrete beam has 300 mm breadth and 500 mm effective depth; effective cover 50 mm, reinforced with 3 nos. 20 mm diameter steel bars at tension side. M20 concrete and Fe 415 grade steel are used. Determine the moment of resistance.
2 a) What is the purpose of providing development length? (5)
b) Design the shear reinforcement for a beam section of width 200 mm and effective depth 500 mm. The factored shear force is 100 kN and it is reinforced with 3 Nos 16 mm diameter bars on the tension side at the critical section. Use M20 concrete and Fe 415 steel.
3 a) Explain characteristic strength of concrete and steel. (5)
b) Explain with figure the stress strain relationship of mild steel. (5)
c) Explain anchorage of reinforcing bars.
4 a) What are T and L beams? (5)
b) Design a rectangular beam section of width 200 mm to resist a bending moment of 30 kNm. Use M20 concrete and Fe 415 steel.
5 a) Differentiate between one way and two way slabs. (5)
b) Design a one way slab with 3.5 m clear span supported on 230 mm thick walls on all four sides. The edges are simply supported. The live load on the slab is 2 kN/m2 . Use M 20 concrete and Fe 415 steel
6 a) When do you require a doubly reinforced beam? (5)
b) Why do we provide reinforcement in two directions in a one way slab? (5)
c) Draw a typical detailing of a continuous slab. (5)
7 Design a slab 3 m x 4 m clear in size supported on 300 mm thick walls on all four sides, and corners held down. The live load on slab 3 kN/m2 . Use M20 concrete and Fe415 steel. Draw all the detailing required for the slab.
8 a) Design a square column to carry a factored axial load of 1500 kN. Use M20 concrete and Fe415 steel. Draw a longitudinal section and a cross section showing the reinforcement
b) What are the purposes of lateral ties in a column?
9 a) Differentiate between long and short columns. (5)
b) Explain limit state of serviceability. (5)
c) Draw a typical detailing for tread riser type stair to show all the reinforcement and mark all reinforcement with assumed values