CIVIL ENGINEERING Paper I
[Time Allowed: Three Hours. Maximum Marks: 200
INSTRUCTIONS .
Section
1. Answer any four of the following: IOx4=40
Discuss 111 =2J with reference to
perfect frame, redundant frame and
deficient frame. 6






For the truss shown above evaluate the reactions at A and B. . 4

c


EI ..'Constant_
the slope and deflection at C in the Beam 'AB.aS shown above. Fin.d also the point of maximum .deflection and its magnitude. 10
B-JGT-J-DFA 2 (Contd.)




Fixed Beam

A


•
ii) Overhang Beam
w

•



Propped Cantilever Beam
State the conditions of static equilibrium for the given beams as shown above. -State whether they are statically deter·
minate or

3 (Contd.)



I·


T


Water seeps near' the bottom of a buried GasQline (sp. gr. =0·68) storage tank and rises to a depth of 1 m as shown in the above figure. If the (ree sUiface of Gasoline is at 6 m above the tank bottOffit fihd the gauge pressure at, a point inside the tank's upper· surface and that at the Gasoline:..water interface. What win be the pressure at the bottom of tank in metres of water q

(Contd.)

B-JGT-J-DFA
..
t
•


The front and ..side views of a centrifugal pump 'impeller rotating at 3000 rpm are as shown in the above figure. If the pump delivers 200
'litres of water per second and the bJade exit angle is 35° from. the tangential direction, detennine the power requirement with the flow. The flow entering the impeller blade row is essentially radial as viewed from a frame. The inner and outer radii are respectively 9 cm and 15 em and the width is 'Constant at 3 em as shown.
B-JGT-J-DFA 5 (Contd.)





A -pump is 2·5 m above the water level in a sump as shown. in the above figure and has a of -22 em of Mercury at the suction side. The suction pipe is of 25 em diameter and the delivery pipe'is a shoJ130 cm diameter
..
.pipe ending in a nozzle of 10 em diameter. If ·the nozzle is directed vertically upwards with its .tip at elevation of 4·0 nt above the 'sump . water level, determine
B..JGT..J:-DFA 6 (Cohtd.)
...


the discharge


input to the flow by the pump and


the elevation up to which the jet would reach above the' sump water level.
Assume ideal flow and neglect all losses in the system.
Take Pwater 1000 kg/m . 10 ·

2. A masonry 6 m high has 1·0 m top width and 4·0 m base width. It retains water on its 'vertical face for its total height. Detennine the stresses that develop' at its base and ,the .section for its stability. Assume the density of the masonry be 24 kN/m3 safe bearing capa­·ci[y,of the soil as 150 kN/m2• unit weight of water as 10 kN/m3 and'the coefficient of friction between masonry and the foundation bed as Factor of safety required against is 1·5. 20
Two wheel loads of 100 kN and 50 kN magnitude spaced at 1·0 m apart, move on a simply supported girder of 8 m span from left right with 50 kN -load leading. Find the maximum pO'sitive shear force and the bending
moment at a section 3 m from the left support. Use influence method. 20
B-JOT-J-DFA 7 (Contd.)
r

3.
10 t

m
Find the thrust at B in the two ,hinged-arch as shown in the above figure. Assume that Ix 10 sec (Jx Ix and are respectively the sectional moment of inertia and the slope of the tangent at and 1
0
is a constant. Neglect' all effects except­bending. 20
.
A horizontal jet of water emerging from an 85 mm nozzle with a unifonn speed, 3·0 mls
...
strikes a vane, and is turned through an f). Neglecting gravity viscous effectsy obtain expressions for the components of anchoring force in tenns of 6,. that are required to hold the vane stationary. Using the expressions so obtained, obtain the anchoring force compo­nents for 90° and 1800 clearly indicating how the magnitude and direction of these forces change with the angle of diversion. The forces need not be computed for these cases. 10
.B-JGT-J-DFA 8 (Contd.)

...

A 2·5 m diameter 'tank of height 2·5 m is closed at, the top and contains a liquid of specific gravity 0·75, up to a height of 2·0 m. If the space above the liquid is under a pressure of (suction)t calculate force acting on the bottom of the tank when it is accelerated vertically upwards at 0·5 times g and the acceleration required for main­taining zero absolute pressure at the tank Take atmospheric pressure as 100 kN/m2 and water density as 1000 kg/m3• 10
4. Determine· the speed and torque required to drive an agitator of 675 rom diameter rotating in
air if similar agitator of diameter 225 mm rotating at 23 rev I s in water requires a torque of 1·1 N-m. Given Pair =1·23 kg/m3, Pwater IOOOkg/m3, J.lair =1·86 X 10-5 }1watcr 1·01 X 10-3Pa-s.Obtain your'resultafteraniving at the relevant group of dimensionless tenns and the corresponding similarity law, considering that the power required is a function of the speed, diameter of agitator, the fluid and viscosity of the fluid in which the agitator rotates. 20
Water flows in a rectangular channel of width 10 m. If the Manning's coefficient n =0:025 obtain a relationship between bed slope and the of flow as a function of Froude number
r
Detennine therefrom the bed slope of the channel required to maintain critical conditions corresponding to a depth of 1m. 8
B-JGT-J-DFA 9 (Contd.)
Water flows in a channel of. unifonn width at a rate of 0·534 m2/s (per metre width). The depth at a particular section in this channel is 70 em beyond this section. the bed is raised by . 15 em. Determine the possible depths of flow at the elevated part of the channel. Identify the actual depth out of the
,possible values. Justify your -answer through proper reasoning. 12
Section-B
5. Attempt any four of the following .

Design a suitable ·fillet weld to connect a tie bar 60 mm x 8 mm to'a 12 nuit thick gusset plate. The pennissible stresses in the tie bar and fillet weld are 150 MPa and 108 MPa respectively. 10


A 5.01 long simply supported' beam carries a superimposed load of 20 kN1m. Design the mid span section of the beam if its effective depth is-kept at 500 mm, using Limit


·State the weight (self) of the beam. Use M 15 and Fe 415 grade steel. 10

Enumerate various types of losses in Pretensioning and.Post':'tensioning.
B-JGT-J·DFA 10 (Contd.)
A dry sandy soil is placed inside a
. 10emx 10emx 10 em cube in its loosest possible state to occupy the entire volume. Its is 1550 g. Then, the soil is . compactedby vibration to occupy the cube in its densest possible state, when it settled by2em. A deposi t of the same soil has a water content of 120/Q and a moist
.defisity of 1·9 glce. Compute the density index (relative density) of the soil in its 'natural state. 5

1m 1m
1m o•
1m

Compute the vertical stress on a horizontal plane at depth of 2 m below the point 0 in the above figure. The area is loaded uniformly to an intensity of 300 10
B·JGT-J-DFA 11 (Contd.)


·.....
0
.A 5m high retaining wall with ..a smooth and vertical back 'retains a. soil having a unit weight of 19·18 kN/m3, undrained cohesion of 16·75 kN/m2 and angle of internal friction of 0• Compute the depth of ttIe tension cracks. What is the resultant thrust on the back of the wall before the formation of tension cracks
after the fonnation ·of tension cracks? 10
6. Distinguish between type' and Through type of Steel Truss bridges.' Illustrate with simple sketches. 6
A simply supported steel beam of 7·0 m span is unifonnly loaded with 40 kN/m. The sections available are MB· 300, MB . 350 and MB 400 and for a· limiting . deflection of of span, the span!depth ratio is 17·9.
. Design the beam, taking Oy for steel as 250 MPa. Z values for M 300, MB 350 and MB 400 are 573·6 cm3, 778·9 cm3 and 1022·9 cm3 respecti,vely. 14
A reinforced concrete short column of 480 mm diameter is ,reinforced with 6 nos. 20 rom dia. HYSD hars of grade Fe 415 and 8 mm dia. Helix with 75 mm pitch. Calculate the maximum load carrying capacity of the column, if concrete used is M 25. Consider' nominal cover of 40 mm to helix. 20
B-JGT-J-DFA 12 (Contd.)
7.

.

Design an. isolated fqoting for an R. C. column of 300 mm x 300 t:nffi size carrying an axial load of 320 kN. The safe bearing capacity of soil is 150 kN/m2. Take M 20 concrete and Fe 415 grade steel. working stress method. Allowable shear stress data are given below: 20
PI
0·25 0·22
·0·50 0·30
0·75 1·00 1·25 . . .., 0·35 0·39 0.·42
1·50 0·45

Results of two drained triaxial tests on a saturated clay are as follows:
•
Compute the cohesion and effective angle of internal friction.
" Sample 1 Sample 2
Cell pressure 80 160
Deviator stress at failure 141·5 . 223·5

B-JGT-J-DFA 13 (Contd.)

What are the corrections that need to be applied to the standard penetration ,resistance
value obtained in a fine. sandy soil-situated
.below the water Why are the correc­tions necessary 5
A 2 m-wide strip footing is placed 1 m below the ground surface of a clay having the following properties:
'ell =80 kN/m2;
=300
The unil weight of the soil .above the water table is 16 kN/m3 and that below the water table is 20 kN/m3:
Calculate the net safe bearing capacity of the footing, adopting a:factor of safety of. 2 for the conditions of the water 6table being. at the foundation level and water table being at the ground level, assuming that
the load is applied at once so that the pore water cannot escape.
the load applied gradually, giving -enough time for the dissipation of the pore water pressure.
Given,
For .Nc Nq 1·0; Ny
tP Nq =22·5; Ny 19·7 10

14 (Contd,)
8. An excavation' has to be made in a 10 m deep . clay stratum underlain by sand. In a trial bore hole made close" to the excavation; the ground
,water was found to rise to an elevation of 3 m below the ground level. What is the safe depth of excavation without its bottom becoming unstabl.e· due to the uplift of the ground water? If the excavation has 19 .be safely made up to a depth of 7 what is the depth to which the water table has to be lowered in the vicinity of the excavation? Specific gravity of the :clay particles is 2·7. Take void ratio of the clay as 0.7. 5

A Clay deposit is 12 m thick 'and draining both faces. The coefficient of consolidation of the clay was found to be 8·64 x 10-4 m2/day. The ultimate settlement of the clay was estimated to be 1·2 m. How long would it take for settlements of 400 mm arid 800 mm to occur? How much settJement would occur in 10 years and 50 years? 20


A 3·3 m x 2·2" m group consists of 9 m long


• piles. It carries a load of 1500 kN. The' . penetrate asand layer (bulk. unit weight 16 1 m thick, and rest in a nonnaUy consolidated clay having a saturated unit
•
B-JGT-J-DFA 15 (Contd.)
of 19 kN/m. specific gravity of 2·7 . and liquid limit. of 50. Clay extends to a depth
I
of 12 m below the top of the sand layer.
I Ground water is at a depth of 1 m below the I
ground surface. Bulk unit weight of sand is
I 16 kNIm3. Compute the settlement in the
if the pile cap rests on the top of sand.
.1 stress distribution to estimate the average increase of stress in Ole clay layer. 15
I
I.

B-JGT-J-DFA 16 .