ies conventional civil engineering 2010

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Sl. No. 520~l I A-GUG-K-DFB'I

CIVIL ENGINEERING Paper II

. .

(Conventional)

Time Allowed: Three flours

· remauung seve1 any FQ

Out of the

rries 40 marks.

The n.un.fbi{~o -rnarks carried by each . subdivisio1 o~q Vjuestio1i is indicated at the end

of the. b ivisionlquestion. Wherever a · questl n i at(e11tpted, all its ·subdivisions 11iust

...... ......__,~ .....

be atteucpted.

nswers must ·be written only in ENGLISII .

"SUllie suitable data, if found necessary, and indicate the same clearly.

Unless indicated otherwise, notations and sy1nbo/s have their usual ·nreanings.

Neat sketches to be drawn, wh~rever required.

(Contd.)

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......... .. ..

1. (a) (i) FoiJowing data arc observed during testing of a Kaplan turbine : Power developed = 2500 k \Al, Head = 60 m and speed = ~50 ~·.p.m. W.hat will be the dimensionless specific speed of .the turbine ?

(ii) Determine the total pressure on a plane rectangular surface of 1 n1 wide and n1 deep whe.11 its upper edge is horiz fa I ~11~ coincides with water surface and ~a :tl l's held perpendicular to water u ·ac~ 2

(iii) The velocity components i at H y directions are given as u = ~ + y · nd v = x..:.... y respectively. Find h ~r these velocity c~mpo~lcnts sati.~~ o Sib1e t\vo dimenSional inc om " · -£S le flow or not ? - 2

(iv) · The diame of he impeller of a centri-fugal gu: n at . llet and outlet arc 20 em and tO respectively. Determine the ·

· n11g m starting speed of ·the pump . ~aa1 s a head of ~~ m. . . 2

(b) (1 · t d the probable hte of a reservotr with an . ttttial capacity of 4 x l 06 m3 if the annual

+ sediment inflow into. r~s~rvoir 4 x 1 0~ 1113.

The average trap eff1c1ency. 0·9 and hfe of . ·a reservoir is terminated when 90 per cent

. (ii) Fuid the wtdth of elementary grav1ty dam whose height is) 00 m. Specific gravity of dam material 2·2 arid seepage co-efficient at the base c = 0·8. 2·

2- (Contd.)

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. (iii) An aquifer of 25 m average thickness is

overlain by an impervious layer of 30 n1 thickness. A test well 0·4 1n in diatneter and two observation wens at a distance of 12 tn aJ)d 48 n1 arc located in the aquifer. After pumping at a rate of 0·2 m3/ s for a long time; drawdowns in the wells wer· observed to be 3 · 5 In and 1· 5 m res ea tively. Determine the coefficient of per n1eability in an/ day.

(i ~) A conical tube of length 2 m \<erti-cally with its sn1al1er end . The vcloci ty head, pressure he a at pper ends arc 1·27 m and 2·50 'R · peetivcly. The velocity head and ~ -e~s r fl ead at lower ends arc 0·203 n no ·407 n1 respectively. Find the direc · t-1 o ow. 2

(c) (i) For a BOD £ t, ·r v sewage (3·0 ml) was diluted ~~ml (capacity of a BOD bottle) TtlU rluted sewage was observed for t ~ts:solvcd oxygen at the beginning ~~ ~ of 5 days incubation at 20°C. The ro~(tbve values were 8·6 mg/L and 4~ 1ng/ L. Determine the BOD of the raw sewage. . . 2

. ~ 11 A tnixed liquor with 2,000 n1g/L of sus-. pended solids has the settled vo]mne of

· 200 n11 from a l_itre of this mixed liquor. Ca1culate its sludge volume index. Is it safe? 2

(iii) If the alum dose to coagulate is 10 p.p.m.1 find out the amount of alUin (in quintals) needed to treat I 0 1nld of water. "\ 2

A-GUG-K-DFB 3 (Contd.)

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•

(iv) For a population of 2 Jac having per capita daily demand of water of 150 litres, determine the water horse power to raise the water from a river of R.L. 120 n1 to treatment plant of R.L. 140 m through a rising main 1 111 in diameter. Assume .2m as th total head Joss due to friction, e~c. pumping efficiency of 70% ..

(d) (i) Estimate the value of coefficient meabiHty for a uniform · a d and of size D 10 = 0·15 mm ob ·n d ·f·om sieve ana)ysis. G = 2·61. 2

(ii) Calculate the a i

2

(iii) l!s\~- o e aghi theory find the uhiinate IS'e1i: · g,. 9apacity for a · square footing

f ·0 m x 2·0 m placed at depth of ....__ ,,_ n1 below the ground on a pure cohesive + soi] havit1g density 18 kN/m3· Nc = 5·7.

Use loc~l shear failure conditions. C = ......_~ 40kN/m.... · 2

~~~ (iv) .A Flow net is plotted for a homogeneous . earthen dam of _30·0 m height with a free

. board of 5·0 in. If K = 6 X I o-4 em/sec, No. of flow channels = 4, No. of potential

• •

drops= I 0, calculate the discharge per metre run of dam. 2


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;

(c) (i)

01) Using Prismoidal Rule .calculate the v o~ of a 5 m deep pit whose top and o tto

(iv}

dhneusions ·arc respectively x~O m and 20 tn x 40 m. 2

A power hous~ has 5 · in1pulsc turbines. Each turbine has two runners. Each runner is insla1led ~ith 4 nozzles. Total discharge is 40 m3-/ s. Find the diameter of jet. Take coefficient of yclocity as 0·985 an~ head as 250m. 4


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(ii) A pipe canying water tapers from crosssection 0·3 1n2 at A to 0·14 m2 at lJ. The average velocity at A is 1·8 m/ sec: and pressure is 441 kN/m2 (gauge). If the frictional effects are negligible, deten11ine the pres~ure at B which is 5·5 ~1 above th Jevel of A.

(b) (i)

(ii) Draw surface profiles cases:

(i)

Steep sloped channel followed by a mild sloped channel. .

Mild sloped channel followed by a steep s1~pe9 channeL 4

(c) Explaining their qualitative differences in respect of total dissolved solids, turbidity and bacterial quality, suggest the units needed for the treat1net1t of water drawn fr01;1 (a) ground, (b) lake and (c) river. · 8


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' (d) What will be the gross and net safe bearing · capacity of sand having ¢J = 39° and density 2·1 t/m3 below (a) 1·0 m wide strip footing

· (h) l·O.m x 1·0 m square footing p1aced at a depth of 1· 2 m below the ground. Take factor of safety as 2·5. Take Nc = 30·14, Nq = 18·4, Nr = 22·4. 8

(c) The observed altitude of {3-ursac Minoris lower and upper culminations are 29°5 ~

and 60°45'3~'- Find tlle latitude of the pia e o observat~on assuming t~e con·ectio ·· r reQ action to be equal to 57 x tangent o a parent zenith distance. 8

3. (a) (i) Show that the hydrosta fi r re remams invariant in a horiz n ' rane parall¢1 to free surface; 4

. (ii) A sudden enl· em t of a water pipeline from 200 n1 to 00 mm. The hydraulic gradient ri · y 10 nun. Estin1ate the dischd gc he pipe. 4

(b) (i) A neb rt sphere of specific gravity 8·0 (al ·n ~n oil of density 800 kg/m3. The di eter of the sphere is I 0 anm. The visco-

+ N-Sec. . · sity of oil is 7 ·848 , · Detcnninc the

. In-. tennina1 ve)ocity of n1etallic sphere. 4

bed slope 'S0 ' is mild or steep according s0

being less than or greater than


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(c) Differentiate between a slow sand fi)ter and a rapid .. sand filter in respect of

(i) Mechanisms of removal of impurities, ~ (ii)

(iii) (iv)

• Cleaning process,

Effluent quality, Bed size in qualitative term.

(d) (i)

(ii) Discuss Pore pressure parameters.

In a 1aboratory vane shear test a

(e)

1 00 mm long and 60 mm dianle·--··-:..·.-.u· pressed into (G = 2·72). A

1 . tn " = 30·876 m, sin 1" =

206265

5·

...,_\H:trizontal distance between A and B . ~~ = 6882·38 m

Angle of elevation from A ~o B = 1 °50'20"

. ......_~ Angle of depression from B to~= 1°51'10';

~~ Height of signal at A.= 4·145 m

Height of signal at B = 3·597 tn

Height of instrument at A = 1·463 m Height of instrument at B = 1·554 m 8

A-GUG-K-DFB , 8 · (Contd.)

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4. (a) (i)

(ii)

A five cy1inders reciprocating pump. raises the · water level by 150 m and the theoretical discharge is 0·20 rr?ts. The velocity in. the delivery pipe is 2·0 ·m/ s. Total head

Joss in pipes is 20 n1. What is the input ~ power, if the efficiency of the pump_ is

0·87? 40 . Two pipes of lengths 2500 m each <t' diameters of 80 em and 60 cn1 respectiv are connected in . paraHe). The · jct~n factor for each 'pipe is 4/ = 0· . otal flow is equal to 250 litres pe sec n . Find the ~ischarge in each pi . 4

. (b) (i) A 5·0 m wide recta~ula~anne1 catTies 15 m3/s of wat~r , i a~elocity of 6 1n/s. State whether 'tl ult jun1p is a possibj- · lity. If yes c f p e ~eight of.the jump and

powe~ d~SJPd · 4

(ii) A tr~~J channel with side slope

_....._.,~ .....

2 fl ts carryir:ag 25 tn3 /s. The slope of the lflnel bed is 1 in 800. Take Chezy's C ~.S and desig~ the channel. · 4

P. o much will be the settling velocity of a sp erical particle A (having specific gravily of 2·65) of diameter 10 x l0-3 cn1. Determine the , size for a floating spherjcat particle having a specific gravity of 0·80 (rising with the same velocity as that of. particle A). Assume kinematic viscocity of water as 1:012 x Io-2 cm2/sec. ·· 8


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(d) In a conso1idation test done in laboratory a samp]c of 20 mm thick consolidated 50% in 15 minutes wHh double drainage. How much time a 5·0 m thick layer of same soil win consolidate 50% and 30% ? If the soil layer has a rock below, how much time it· will tak to consolidate 50% and 30%?

(e) The speeds of overtaking and ovc a ·e vehicJes are 80 kmph and 60 kmpA e. e tively. If the acceleration of the o. 'ertaking vehicle is 2·5 kmph per second calcu-a e the safe passing sight distance fa · i1tgle lane one way traffic (ii) three Ia B way traffic. Assume perception tim o dr~er = 2 sec. 8

5. (a) (i) A reaction tuli i h ing inlet diameter as 1·0 m ~ a ~ tat1cma·1 speed· 400 r.p.m. has flow. e· ·~5 m2 at the inlet and is workirt un er a head of 65 n1. Flow is rad'a t ~ outlet. Cotnpute the hydraulic

o e ~ and power devc·loped by the ~ taking velocity of flow at inlet as

n"'s~ m/s and ve]ocity of whirl at inlet as V 25·0m/s. 4

~ii) Find the critical depth for a discharge of 4 1n3/ sec for flow in right angle triangular channeL . . 4

(b) (i) Two reservoirs are connected by a pipe 100m long and 100 n1m in diameter fol1owed by another pipe 60 m long and 50 mm in diameter. The total head loss between the reservoirs is 10·3 m. Given f ;:;;; 0·03. co·n1pute discharge ncglecling minor iosres. 4

A-GUG-K-DFB

' ;

10 (Contd.)

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(ii) The . velocity distribution within the

6. (a)

. 4

A-GUG-K-DFB (Contd.)

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(ii) An oil having viscosity 0·08 Ns/m2,

specific weight 8829 N/m3, density 900 kg/m3 flows at the rate of 5·4 x lo-3 m3/s through a horizontal circular pipe of 0·12 m

(b) (i)

(ii)

diameter and length 150 1n. Find (i) pressure difference in 150m lengt

kN/m2 0

(ii) wall shear stress in Nltn2 a~ (iii) average and maxin1um vel ~ city. 4

depth .of How in having side. slope

4

The BOD rate constant (k) for a river~s BOD ~ssimilation was determh1cd to be 2·0 day-1

· (base CJ. The BOD of this· river after leaving a · heavily populated town was detennined to be

50 mg/L. Determine the distance after which ... the river~s BOD wou1d becon1e 4 mg/L when . .... the average velocity of the river was· I m/scc. What would have been the K value if this distance would have been 300 km and stale what· K 1nanifests. 8


L.__ ____ - -

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(d) A 6·0 m high retaining w"ll is to suppon a soil \Vith unit weight r = '17·4 kN/m3, ~ = 26° and c' = 14·36 kN/m2.·Determine the Rankine active force per unit ·length of wall before the tensile crack occurs.· Find the ctitical depth.

8 (e) A locon1otivc on B.G. track with four pairs of -----driving wheels each carrying axle load o

20 tonnes is required to haul a train at a sg€ed of 80 kniph. The train is made to .run ~ a level track with curval!Jre of io. Ca ate t e maximum permissible load that ca ul1ed

by the engine. Take hauHng o ac ty ! time

the Joad on driving wheel 8

7. (a) (i) Show that the mos ef i trapezoidal channel section s \a i regular hexagon

4

(ii) Design tt sition using Mitra's hyper- .. boti transltton given by

Be Bf Lf . . Bx- ( ) + ·Lf/Jc- Be- Bf X .

. . semi-cubical parabolic transition given by

~ ·· Given nominal bed width = ·25 111, width of flumed section = I 0·0 m and tota11ength of transition = 15·0 m. 4

A-GOG-K-DFI3 13 (Contd.)

\

. t

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(b) (i) The shear stress ~ in open channel depends on depth of flow y, velocity v, density.p~ surface tension a and acceleration due to gravity g. Using Buckingham's Pi Theorem, make out the dimensional analysis of the problem. ~

(ii) The depth of moisture in_root zone , ~ capacity and permanent wihin~o ~R r

. m depth of soil c;tre 0·5 m/m ar{~ O·~\'·m?n1 respectively. Compute the fie]~acity. and penn anent wilting p f. ¢fake dry weight of soil as 13· ~ LJ 3. 4

(c) On the basis of a detent1 riod of 24 hrs, determine the· size ( ss r:j.ng 1ength to width ratio of around· an epth of waste warer about J m) ot ~'e tic Tank required for a large house O\i ~n g 100 persons. The flow into the · ~ 1a I be assumed at the rate of 70 .lpc will be the surface loading and e~ len veir loading of the tank ? 8

(d) ·-~50 x 450 nun concrete pile 2.0·0 ·m long is " dnv. n into sand deposits wilh. Y = 17 kN/m·..,

an <!>' = 30°. Find the ultimate load ic point <foad QP by Meyerhoff's metl.1od and Janbu method.

. MeyerhofCs Nq' = 55, Atmospheric pressure ;;; 100 kN/m2, Janbu's Nq' = 18-4. 8

(e) (i) Fron1 the following. tidal data detcnnine the wave height and wave velocity for a non-translatory wave . Depth of water = 3 n1

Fetch = 800 km 4

A-GUG-K-DFB 14 (Conld.)

..

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(ii) What are · the considerations for determining the thickness of concrete lining in a tunnel. Find out the concrete lining thickness for ~ tunnel with a bore diameter of 7·6 In. 4

8. (a) (i) Flood frequency computation yields following results:

Return Period Years

50·0

100·0

,

(ii) -Show th t P a p-late 10m x 5 m is towed throug: · ~ so that the boundary layer is 9iil:i'f I laminar~ the ratio of ,towi.ng sp6bffs so that the drag force rcmams to~tant regardless of whether 10 m or 5 n1 ~'ide is in the flow direction is given by

·u lOm = 1·2598

Usm

If the ·boundary layer is entirely turbulent ·and J{eynolds number is less than 107,

Uwm = 1·08. 4 Us rn,

A-GUG· K-DFH 15 : (Contd.)

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,

(b) (i) A rectangular channel 15 m wide has a nonnal depth of 0·8. The discharge carried · is 10 m3/s, what is the alternate depth?

4 (ii)

(c)

8

(d) A re an u r foundation 6·0 m x 3·0 min size exert: pressure of 20 kN I m2 to the soil u ~9r eath. Compute the increase of vertical tn{ss at a point 0·5 1n below the centre of

foundation. Use Boussincsq equation. 8

Determine the ·radius of a taxiway for · a supersonic aircraft to neg~tiate the curve at a turning speed of 50 kmph. rhe wheel base is· 35 m and the tread of main landing gear is 7·~ m. -The airport is of type A as per ICAO. Assume co-efficient of friction between tyre and paven1ent surface as 0·13. 8

A-GUG-K-DFB 16

ies conventional civil engineering 2010

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