Engineering Services EIan1inatior+2D1 2. 5N°- -FTF-M-DJA CIVIL ENGINEERING Paper I (Conventional) '.Iime.Allowed .' Three HoursMaximum Marks 3200 _ . INSTRUCTIONS Candidates shouldattemptany FIVE'questions. The numberof markscarriedby each subdivisionof a questionis indicatedat the end 'of the subdivision. Thetotalnumber of marks for eachquestion will be 40. Answers mustbe writtenonlyin ENGLISH. Notations used are standard and will have their usualmeanings,unlessotherwise indicated. Assumesuitabledata,if found necessary, and indicatethemclearly.Newtonmay be converted to kgf using the relation 1 kilonewton (1 kN) = 100 kg}; if found necessary. Important: Candidates are to notethat all partsand subpartsof a question are to beattempted contiguouslyin the answer-book.That is, all partsandsub-parts of a question being attempted must. be completedbefore attemptingthe next question.- Anypagesleft blankin theanswer-book mustbeclearly struckout. Answersthatfollow pagesleft blank may not be given credit. 1. (a) List the principal constituentsof fly ash. Explain its pozzolanicaction when used in concrete. (b) 10 For__ a mix designof proportion1 :2; 3-6 (by mass)with--we ratio of 0-45 and air-content 3%_ '_ of the concrete volume,calculate the weightsof water,cement,ne aggregateand coarseaggregate to make.1 m3 of concrete. The specic gravitiesof cement,EA. and are 3-15, 2-65 and 2-6 respectively. 10 (c) What are the varieties of industrial timber ? Indicate theprocedure followed formaking ' bre boards. (d) 10 '(a) Discuss the properties imparted tobrick-earth --byits constituentsaluminaand silica. 2. 10 0.2RN Aluminium 0-2 kN-m \ Copper A strip of copper.40 mm wide and 10mm thick is bonded with "another strip of aluminium of samesize to form a bimetallic strip of 40 mm x 20 mm. The strip is subjectedto a purebendingmoment C-FFF-M-DJA 2 of 0-2 kN-m asshownin the above "gure. Calculate the radius of curvatureof the strip and the maximum tensile andcompressive stresses. EC, = 1x 105MPa; IO0MPa (b) -it-_-I-I - E E 8 n . J_ 1.'¢F7_-_-:"?.." A ____.______,.D 9: 100 MPa 500mm :4 A squareplate of side 500 mm is subjectedto pure shear of intensity 100 MP3 as shown in the above gure. Youngs modulus of the (c) material is 2 x 105MPa and Poissonsratio is 0-2. Find the principal stresses,their directions and the change in lengths of the diagonals of the plate. 10 A thin walled tube of circular crosssection with outer diameter 100 mm, thickness 2 mm and length 1000 mm is xed at one end. It is subjected to a twisting moment of 1 kN-m at the free end. Find the shear stress in the wall of the t_ube_ and the angle of twist at the free end. E = 2 X 105 MPa and Poisson's ratio = 0-25. What will be the shear stressin the wall of the tube if the crosssectionof the tube is square C-FTF-M-DJA 3 with outside dimensions 100mmx 100mm andwall thickness 2 mm? "* 10 3--(3) ..:;.§__ :I£.-- I Find all the support reactions and draw BM diagramfor the frame shown above.Framehas 'hinged sqpports at A & B a_.ndIin't_ern'aI hinge at C. _ ' . - 15 (bf Analyse theframe shown above byeompatibility method..131 is 'constant. Draw BM and SF diagrams. " '' C-FTF-M-DJ A 4 '25 (Contd.) '- U.D.L.15KN/In 2 iv " |< 3m '|'' mam Analyse the rigid frame shown in the above gure by momentdistributionmethod,taking flexural rigidity E1 to be uniform for all members. 20 I (b) ISMB 450\is used asapropped cantilever beam of span12m.Assuming cry= 250MPadeterminethefactored uniformly distributed loadqu the beamcancarry includingself weight,if the loadisto beappliedovertheentirespan. The propertiesof ISMB 450 are asfollows : weight/metre : 72-4kg area of cross-section : widthof flange : 150mm thickness of ange : 17-4mm I = 3-039x 103mm. 1 = 3-34x 106mm4 20 C-FTF-M-DJA 5- 9227 mm2 (Contd.) 5. (a) Rolled steel section ISWB 300isused asa columnof height6 m, xed at baseandpinned at top. Find the permissiblecompressive load on the column using the table of- permissible compressivestressesas given in the table below: Crosssection properties of ISWB300section are as follows : ' Areaof cross-section = 6133mm2 Flangewidth. = 200 mm Flangethickness = 10mm Web thickness = 7-4 mm In _ -_98-216 x 106mm = 9-9 x 106 mm4 EMMMM EMWEE EMMM (b) "320mm X 14mm plates 320mm x 8 mmdoubleeoverplates A doubleco_\{er butt joint is providedwith the following details: Size of plates to be spliced 320 mm x 14mm ' Size of cover plates 320 mm x 8 mm No.of20mmdiarivets provided =7 ~ (as shown in the above gure) Allowable stress in tension 125 MPa . Allowablestressin shear L 80 MPa Allowable stressin bearing 250 MPa (i) Determinethe strengthof the connection. (ii) "Findthe force_onthe extremerivet when the connection is subjectedto a pull of 280 kN with an eccentricity_of20 mm. (iii) Find the limiting valueof eccentricityif force on any rivet is not to exceed its strength. ' tC-FTF-M-DJA - 7 25 (Contd.) -w 6. (a) Distinguish clearly between pretensionedand post-'tensi'oned prestressed concrete"bringing out all the operationsinvolved. 8 (b) A simply supported T-beam of span 9 m in reinforced concrete has the following dimensions : Flangewidth ~- = 2000mm Flangethickness = 150mm Overall depth = 750 mm Rib width = 300 mm The beam is provided with 6 No. 32 mm diameter'HSD bars of grade Fe 500. Concreteusedis of gradeM 25: Find the moment of resistance of the beam using limit statemethod. Also nd the magnitudeof two point loads at 3 m distance from the ends. 12 (c) A rectangular simply supported prestressed concrete beam of cross-section 200 mm wide and 300 mm deep is prestressed.by 15 No. 5 mm diameterwires locatedat 65 mm from soft and 3 No. Smm diameter wires at 25mm from the top. Assuming effective stress in steelwires as 840 N/mmz, (i) calculate the stnessesin concrete at the extreme bres at midspan section due to prestressand its own self weight over a span of 6 m. C-I-"TF-MDJ A In 8 (Contd.) (ii) if auniformlydistributed workingloadof 6 kN/m is imposed on_the beam, obtain the maximum compressive stress in concrete. (iii) if themodulus of rupture of concrete is 6-5 Nlmmz, estimate the load factor against cracking. Assume density ofconcrete =24kNlm3. 20 7. (a) (i) Calculate the time required to grade and , nish 30 km of road formationof 9-0 In width for two-lane road with motor- graderhaving width of 3-0m, using six passes with speed for each of the successivetwo passesas 5 kmph, 7 kmph and 9 kmph respectively. Assume machine efficiency based on operator skill, machine characteristics working conditions as 80%. and 6 (ii) Enlist major concreting equipments required"to carry out following operations: Mixing, transportationdelivery and compacting equipment. 4 (b) (i) Calculate numberof transit mixers (TM) required for transporting concrete from central batching -plant to site. The cycle timedataof a 6 _m3 typicaltransitmixer ' is given below : " Loadingtime of TM = 6-0 minutes. Travel time of loaded TM to site = 300 minutes Averagewaiting timeat site= 5-0minutes Discharge time of concrete at site through concretepump = 1_5minutes Traveltimefor return-trip__= '24 minutes If the central batchingplant having ' averageoutputof' 60 m3j,l hr is to run _co_ntinuo1isly, work out therequirementof no. of concretepumpsandTM. 6. (ii) Name.various types of Earth Excavating Equipmentsand give their corresponding digging "depth. . 4 (c) The data for planning a certain Civil Engineer- _ ing project by CPM.-Networkanalysis is given below. Draw the network and establish the criticalpath. Also determine the following: " (i) Preparea CPM' schedule and calculate total float, free oat and independent oat. C-FI'F-M-DJA ' 10 (Contd.) (ii) Compute the project duration : 9 c I c Acnwty immediately 9 n Preceding Following (d) (i) PERTcalculationsindicatethatduration of a given project is 72 weeks.With the variance of 15, work out number of weeks within which the project is expec- ted to be completedwith probability of 50%, 80% and 98%. Take Z-valuesof 0-89 and 2-1 for-probabilityof 80% and 93% respectively, '5 C-FTF-M-DJA 11 (cemd.j .-(ii) For an activityof castinga raft founda-'tion of. a High rise building, three engineers A, B and C have given the _ _time_estimatesas follows. State who is niorecertain aboutthetimeof completion of job. Also calculateexpectedtime of completion of eachengineer. _ - Engineer 1 _ Times in week ' - Optimisnc 11:40-St Pessimistic . 'like!y _ I .J_rJ-"*_..' i:I ' - '| :I : I.:__ i . . I I. I' . - ..-' .- .-' I I- . ' . . .'_ _'. F.-, - CF1F-M-DJA . ' 5: _'.-.I in . 12_. " ' _v" . 5