DESIGN PREVIOUS QUESTION PSPER-1

III B.Tech I Semester(R05) Supplementary Examinations, May/June 2010

BASIC REINFORCED CONCRETE DESIGN AND DRAWING

(Civil Engineering)

1. Design a simply supported rectangular beam to carry 35kN/m superimposed load over a span of 5m

on 400mm wide supports. Use M20 grade concrete and FE 415 grade steel. Check the design for all

necessary conditions. Draw to a suitable scale

(a) Longitudinal section showing the reinforcement details.

(b) The cross section of the beam at salient points, showing reinforcement details.

2. Design a continuous RC slab for a hall 6.5m and 13.5m long. The slab is supported on RCC beams

each 250mm wide which are monolithic. The ends of the slab are supported on walls. 350mm wide.

Design the slab for a live load of 2.5 kN/m2. Assume the weight of roof ¯nishing equal to 1.5 kN/m2.

Use M15 concrete and Fe 415 steel.

(a) Draw the reinforcement of the slab in plan view

(b) Draw cross section of the slab including beams with reinforcement details.

3. A rectangular beam 25cm by 50 cm deep is reinforced with 3-12 mm bars in compression zone and

4-25mm bars in tension zone, each at an e®ective cover of 40mm. Determine the forces in compression,

force of tension, cracking moment and moment of resistance assume

(a) M20 concrete and Fe 415 grade steel

(b) M25 concrete and Sail MA410 grade steel.

4. (a) Discuss the main factors that a®ect permeability of concrete.

(b) Explain the signi¯cance and role of aggregates in dictating the fresh and hardened     properties of concrete.

5. Draw axial force moment interaction curve for a rectangular column with 4% steel distributed equally

on two faces. Assume a minimum of 12 bars placed at an e®ective cover of 0.2D.

6. (a) What are the situations in which combined footings are preferred to isolated footings?

(b) Why it is necessary to ensure, by proper proportioning of footing that the bearing pressures

underlying all footings in a building are more or less same order of the magnitude.

7. A 15cm thick roof slab is reinforced with 12mm bars @ 120mm center in each of the two directions.

If clear size of the room is 4.5m £ 5.5m and edges are simply supported and free to lift, determine

the maximum superimposed load that can be placed on the slab safely. How much more load can be

supported if the corners are held down

.

8. (a) Explain structure of a hydrated cement in diferent stages of hydration.

(b) Explain the process of gel formation and capillarity action during hydration