# sathyabama university

```Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act,1956)
Course &amp; Branch :B.E - P-CIVIL
Max. Marks:80
Title of the Paper :Reinforced Concrete Structures - II
Sub. Code :620PT501(2007-08-09-10)
Time : 3 Hours
Date :03/05/2012
Session :FN
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1.
PART - A
(10 x 2 = 20)
How bending action of a circular slab differs from that of
rectangular slabs?
2.
State any two limitations of direct design method of flat slab.
3.
List the modes of failure of a retaining wall.
4.
What is the significance of base key in retaining wall? How it is
provided?
5.
What are the different types of joints in water tanks?
6.
Why the columns of elevated tanks braced?
7.
Distinguish between bunkers and silos.
8.
What are the assumptions made in Janssen’s theory of silos?
9.
What are the different types of stairs?
PART – B
(5 x 12 = 60)
11. A circular room has 5m diameter from inside. Design a circular
roof slab for the room to carry a superimposed load of 3800
N/m2. Assume that the slab is simply supported at the edges. Use
M15 mix and HYSD bars.
(or)
12. Design an interior panel of a flat slab having equal panels of 6m
x 6m. The panels have drops of 3m x 3m size. The depth of the
drop is 250mm and that of slab is 200mm. The internal columns
are 500 mm diameter and the column head is 1000 mm in
diameter. The storey height above and below the slab is 4m. The
partition walls
13. Design the stem, heel, toe and key of a retaining wall to retain the
earth 4m high. The top surface is horizontal behind the wall but
subjected to a surcharge of 17kN/m2. The soil behind the wall is a
well drained medium dense sand with following properties:
(a) unit weight  = 17kN/m3
(b) Angle of internal friction 
= 30o The material under the
wall base is same as above with SBC of 150kN/m2. The
coefficient of friction between base and the soil is 0.55. Design
the wall using M20 grade concrete and Fe415 steel.
(or)
14. Design a Counterfort retaining wall to retain 7m high
embankment above ground level. The foundation is to be taken
1m deep where the SBC of the soil is 180kN/m2. The top of the
earth retained is horizontal, and soil weighs 18 kN/m3 with angle
of internal friction  = 30o. Coefficient of friction between
concrete and soil may be taken as 0.5. Check the stability of the
wall and find the pressure distribution only.
15. An open rectangular tank 4m x 6m x 3m deep rests on firm
ground. Design the tank. Use M20 concrete and Fe 415 steel.
(or)
16. Design a wall of a rectangular water tank for a direct force of 60
kN/m and bending moment of 40kNm/m, if tension is on liquid
face. The materials are M20 grade concrete and HYSD
17. Design the side walls and hopper bottom of a 3m x 3m square
bunker of capacity 3 Tonnes to store coal using M20 concrete
and Fe415 steel. Given unit weight of coal = 9 kN/m3, angle of
repose of coal = 30o.
(or)
18. Compare and comment on the horizontal pressures developed at
5m intervals in a cement silo of internal diameter 10 m and
height 30 m using Janssen and Airy’s theories. Take density of
cement = 15.2 kN/m3, Coefficient of friction between concrete
and cement  '  0.554 , Coefficient of friction between wall &amp;
material   0.316 , Angle of
repose of cement   17.5o , Ratio of
horizontal to vertical pressure k  0.54 .
19. Design a dog-legged stair for a building in which the vertical
distance between floors is 3.6 m. The stair hall measures 2.5m x
5m. The live load may be taken as 2500 N/m2. Use M15 concrete
and Fe 415 steel.
(or)
20. Figure shows a general arrangement of a staircase of a building.
The risers are 150 mm and the treads are 250mm. Design the
staircase for a live load of 3000 N/m2. The width of the stair is
1.5 m and the width of the wall is 400 mm. Take c   cbc  5N / mm2
and t   st  140N / mm2 and m = 18. Adopt unit weight of concrete as
2400 N/m3.
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