Indian Foresl Service ExaminaEo,-' ·2013
IA-JGPT-M-DJFo-A I
CIVIL ENGINEERING Paper-I
ITime Allowed: Three Hours IIMaximum Marks 200 I
OUESTION PAPER SPECIFIC INSTRUCTIONS
Please read each of the following instructions carefully before attempting questions.
There are EIGHT questions in all, out of which FIVE are to be attempted.
Question no. 1 and 5 are compulsory. Out of the remaining SIX quest.iQns, THREE are to be attempted selecting at least ONE question from each of the two Sections A and B. Attempts of questions shall be counted in chronological order. Unless struck off, attempt of a question shall
be counted even if attempted partly. Any page or portion of the page left blank in the answer book must
be clearly struck off.

All questions carry equal marks. The number of marks carried by a question part is indicated against it.
Answers must be written in ENGLISH only.
Unless other-wise mentioned, symbols and notations have their usual standard meanings.
Assume suitable data, if necessary and indicate the same clearly.
Neat sketches may be drawn, wherever required.
SECTION-A
Q. l(a)Compute the bending moment and torsional moment diagram of the cantilever circular bow girder in the
shape of quadrant of a circle of radius 2m and carrying concentrated load (normal to plane of the structure)
of 20 kN at the free end. 8
Q. l(b)Write down the stiffness matrix of a truss member in a plane truss in member oriented axis.
What will be its form for structure oriented coordinate axis? Take L Length of the member,
A =Area of cross-section, E =Young's modulus, a angle between member axis and structure oriented axis. 8
Q.l(c)Find the time period of oscillations for a block of mass hangs as shown in Fig.1 and 2. 4+4
<img src='./qimages/1209-1c.jpg'>

Q. 1(d)On a soft glacial clay layer 2 m thick with 45% liquid limit, the pressure intensity was increased from
400 kPa to 800 kPa. If the original void ratio was 0.67, calculate the settlement due to this pressure increment.

Q.1(e)Determine the thickness of boundary layer at the trailing edge of smooth plate of 5.0m length and 2.0 m width.
The plate is moving with a velocity of 5.0 m/sec in a stationary air. The kinematic viscosity of air is 1.5 x 10-5 m2/s.
Also determine drag force on one side of a plate if density of air is 0.125 slug/m3. 4+4

Q.2(a)A cantilever beam of span 3m is subjected to a vertical load of 1.0kN at the free end. The cross-section of the
beam consists of equal angles 100 mm x 100 mm x 12 mm with one of its legs placed vertically. Find the magnitude
and direction of the resultant deflection.
Given Iuu=329.3cm4,Ivv =84.7cm4,E=2 x 105 N/mm2; centroidal distance =29.2 mm. 15

Q.2(b) A system of wheel loads 40kN, 60kN, 60kN and 20kN separated by distances 2m, 2m and 1m respectively
crosses a simply supported girder of 20m span from left to right. Determine the absolute maximum bending
moment in the girder. 15
Q.2(c)Determine the vertical displacement of the joint C of the frame as shown in Fig. Area of cross-section
of each member is 850 mm2 and E 200 kN/mm2. 10

<img src='./qimages/1209-2c.jpg'>


Q. 3(a)Analyse the portal frame as shown in Fig. by slope deflection method. Draw the bending moment diagram. 20
<img src='./qimages/1209-3a.jpg'>

Q. Determine the bar forces in the member CB, BE and EF of the truss as shown.
<img src='./qimages/1209-3b.jpg'>

Q.3(c)Draw the influence line diagram for reaction at A and shear force at X for the continuous beam as shown.
(Detailed calculation is not required)
<img src='./qimages/1209-3c.jpg'>

Q. A prestressed Concrete Beam 200 mm wide and 300 mm deep is prestressed with wires (Area 320 mm2)
located at a constant eccentricity of 50 mm, carrying an initial stress of 1000 N/mm2.
The span of the beam is 10m. Calculate the percentage of loss of stress in wires when the beam is under post tensioning.
Assume the following data
Es= 210kN/mm2; EC= 35 kN/mm2
Relaxation of steel stress of the initial stress
Shrinkage of concrete 200x10-6
Creep coefficient 1.6, Slip at anchorage 1 mm
Friction coefficient 0.0015 per m. 10

Q. 4(b)Two triaxial tests are performed over a c-pie soil. In the first test, the cell pressure is 100 kPa and failure
occurs at an additional axial stress of 450 kPa. In the second test, the cell pressure is 200 kPa and an additional
axial stress of 725 kPa causes failure. Determine important soil parameters. 10
Q. 4(c)What are the desirable characteristics of Grouting in soils? Illustrate some of the grouting methods
adopted in practice. 5
Q. venturimeter is fitted in a 40 cms. diameter horizontal pipeline which has a throat diameter of 15 cms.
The pressure intensity at the inlet is 1.4 kg/cm2 and at the throat it is 40 cms. of mercury of vacuum pressure.
Determine the flow of water. Assume of differential head loss between inlet and throat.
Find also the value of coeff. of discharge of venturimeter. 15



Q.5(a)The principal rafter of a steel roof truss consists of two unequal angles of 125mm x 75mm x 10mm
placed back to back on opposite sides of a 10 mm gusset plate with 75 mm legs turned out.
The length of the rafter is 1500 mm. The purlin reactions is 20 kN and acts normal to the rafter at a distance
of 600 mm from one of the nodal points. The rafter axial compressive force in the rafter is 200 kN.
Check the adequacy of the section. Given the f 250 N/mm2.The following are the properties of
the section
i.e 2 125mm x75mm x10mm
Area 3804 mm2;
6.006x 106 mm4
Cxx 42.4 mm
Dead load (self 292.3N/m
rxx 39.7mm
ryy= 30.7mm
(Refer to the Table-1 for Allowable Stress in axial compression) 8
Table-l
fy(yield stress) 250N/mm2

Slenderness Ratio (lamda) 30 35 40 45 50 55
fc-Compressive stress 145 142 139 135.5 132 127

Q. 5(b)Define Mechanism. Sketch the common mechanism of failure in structures. (No explanation is needed.) 8
Q. 5(c)Determine the safe bearing capacity for a footing located at 1.5m below ground level.
The soil is silty sand and has the following properties
C=5 pie= gaama= 18kN/m3, F.S. 3
The water table may rise to the ground level. If the footing width is 2m, find the load carrying capacity per metre.
Take Nc=24 Nq=14 N sigma =16 for pie=28° 8

Q.5.(d)A semi circular channel carries uniform flow of 10.0 m3/sec and it runs full. Consider
Chezy's coeff. c 60, bed slope 1/3600. Determine the diameter of the channel.
Also determine the cost of lining for 1.0 km long channel considering cost of lining at the rate of Rs.800/sq.m. 8
Q. 5(e)An orifice meter having orifice diameter of 10cms is fitted in a 200 mm dia pipe which is laid horizontally.
The manometer reads 30 cms of height of mercury. Determine the discharge of oil flow of sp.gr. 0.8. Consider
coeff.of discharge =0.60. 8

Q.6(a)Determine the bed width and depth of flow of most efficient trapezoidal channel to carry
the discharge of 4.5 m3/sec at a velocity of 1.2 m/sec. The side slopes are H).
If Chezy's coeff. C 55, determine bed slope. 10

Q.6(b) A 40x20 cms venturimeter is fitted in a vertical pipe of 40 cms diameter which carries
oil of sp.gr. 0.9. The difference of elevation of inlet and throat is 40 cms.
The U tube manometer reads 30.0 ems of mercury deflection.
Determine:
The discharge in a pipe.
(ii)Difference of pressure between inlet and throat.
C sigma of venturimeter 0.98 and the flow is vertically upward. 15

Q.6(c)Fig.1 shows the section proposed for the top chord member of a Bridge truss. The
effective length of the member is 4.75m and it has to carry a maximum compressive load
of 1000 kN. Investigate the safety of the member. Assume fy 250 N/mm2 .

<img src='./qimages/1209-6c.jpg'>

Fig. 1
Properties of the section adopted -978mm2
Cxx= 27.3mm;Cyy 12.4 mm
Ixx 6.19 x 105 mm4;
Iyy 1.85 x 105 mm4.


Ref Table-l Safe compressive stresses for steel of fy 250 N/mm2
Table-l

Slenderness Ratio 35 40 45 50 55
Safe axial compressive stress 142 139 135.5 132 127

Discuss the stress-strain curve of steel and its application under Plastic Analysis.

Q. Prove that the shape factor for a triangular beam section as shown in Fig.2 is 2.352.

<img src='./qimages/1209-7a.jpg'>

Q.7(b)A group of 9 piles, 5m long and 200 mm in diameter, is arranged in a square form with spacing
of 500 mm centre to centre. It carries a total load of 500 kN. The piles are embedded in normally loaded clay
with Y sat= 20 kN/m3, LL e 1.05. Hard
stratum is available at a depth of 7m. Calculate the settlement of the pile group. 10

Q.7(c)(i)Sketch the shear-stress distribution for the following sections (under pure shear)
A.T-beam B.I-section. 2.5

Discuss the importance of Diagonal tension in R.C.Beams. 2.5
Explain the various components of Plate Girder.2.5
Explain the serviceability requirements in the design of R.C. slabs. 2.5
Q. 8(a)Determine the value of at collapse of a three span continuous beam shown in Fig.
The plastic moment capacity of the beam is constant for all spans. 20
<img src='./qimages/1209-8a.jpg'>

Q.8(b)In a 6.0 m wide rectangular channel the flow takes place at a velocity of 1.5 m/sec with a depth of 0.75 m.
Determine:
(i)Critical depth.
(ii)Whether the flow is super critical or sub critical?
The alternate depth of this depth of 0.75 m.

Q. A 1.0m diameter well is sunk to a depth of 15m in a bed of soil with permeability of
0.1 cm/minute. The ground water table is 2m below surface. The depth of water in the well is not to fall
below 1.0m while the drawdown at a radius of 1.0 km is to be limited to a maximum of 0.5m.
Calculate the yield of the well assuming there is no pumping and the water table is horizontal.