NICMAR PGP-CM
Determine the output of a bulldozer from the following operating conditions Material !ands well " #$% &aul Distance " '$m Rated mold board capacit( " ) cubic meter *loose +olume, -perating factor '. minutes/ hour !olution Probable round trip time Pushing '$ m 0 #1. 2mph " $345 minute Returning '$m 0.2mph " $3'6 Minute 7oading shifting gear " $3)$ minute Minutes 8ime per 8rip" 93:' minute 8rip per &our" )'3. 8rips Net mold board capacit( " )/93# " #3. -utput per hour"#3.;)'3." 653#. m) output per da(" 653#.;6 *hours," 54$ m) cutting and dozing of 9$$1$$$cum of earth" 9$$1$$$/54$"9'. da(s <=uipment operating cost 8he cost of operating the e=uipment includes fuel costs1 routine maintenance costs1 ma>or repair cost1 operators cost1 t(re replacement cost1 and o+erhead costs3
Fuel costs: cost of fuel consumed in one hour " cost per litre ? hourl( fuel consumption &ourl( fiel consumption " &ourl( fuel consumption at full load ? operating factor3 8he fuel price litre1 deli+ered at the site is obtained from the local suppliers at it +aries from place to place3 8he rate of consumption depend upon the t(pe of engine *diesel or petrol,1 the state of the engine and the wor2ing conditions3 Diesel engine fuel consumption per hour " $39. litres ? rated &P ? load factor Petrol engine fuel consumption per hour " $3## litres ? rated &P ? load factor3 For example:
NCP#'/#.Page 9
NICMAR PGP-CM
the hourl( fuel consumption of a crawler tractor rated with #.$ &P1 operating under a+erage conditions *load factor :$ %, and diesel costing Rs3 ). per litre31 can be wor2ed out asunder Diesel consumption per hour " $39. ? Rated fl(wheel &P ? load factor " $39. ? #.$ ? $3: litres" #53#. litres Cost of hourl( consumption " Diesel consumption ? rate of diesel per litre" #53#. litres ? Rs3 )." Rs3 4963:.
Routine maintenance costs: Maintenance costs include the cost of lubricating oil1 grease1 filter batteries1 minor repairs1 and the labour in+ol+ed in performing maintenance3 8he maintenance cost including ser+ice1 labour cost and minor repairs +ar( with the t(pe of e=uipment in+ol+ed and the pro>ect en+ironment1 and these can be appro;imatel( calculated as proportion of hourl( fuel cost as follows3 -perating conditions &ourl( maintenance cost @a+orable A+erage 9/' fuel cost 9/) @uel cost
Anfa+orable 9/# @uel cost Ma>or Repair cost Repair cost " Depreciation cost ? Repair cost Repair cost during nth (ear " n ? Balue to be depreciated / Digit sum of e=uipment life in (ears @or e;ample If the total +alue of depreciation of a wheel e=uipment *repair factor " $3:., wor2s out as Rs3 ):.1$$$ and its life is . (ears1 than the repair cost during each (ear of operation*wor2ing 9.$$ hours per (ear, can be estimated as under 8otal repair cost " 8otal depreciation ? Repair factor " ):.$$$ ? 3:." Rs3 #69#.$ 8(re cost for wheel e=uipment 8he t(re manufactures pro+ide indication of t(re life but these should be ta2en as guidelines3 &ourl( t(re replacement cost " 99. ? t(re price ? no3 of t(res / 8(re life in hours
NCP#'/#.Page #
NICMAR PGP-CM
Example: If the four t(res of an e=uipment each costing Rs3 #.$$1 are replaced after 6$$ hours and the t(re can be recapped locall(1 then the hourl( t(re cost calculated as follows " 99. ? ' ? Rs3 #.$$ ?$36 / 6$$" Rs3 99./hr
Manpower cost: An e=uipment re=uires operators1 dri+ers and helpers for its operations3 8he number of persons wor2ing on an e=uipment +aries with t(pe of e=uipment3 A dumper ma( ha+e onl( one dri+er-cum-operator whereas a bulldozer will need one operator and a helper3 Depending upon the persons re=uire per machine1 the pre+alent wage rates and the facilities pro+ided b( the compan(1 the hourl( manpower costs can be calculated3
Selection of Construction Equipment: Proper selection of e=uipment increases the speed of construction and ma2es pro>ect most economical3 !ome general consideration ma( be made for selections of construction e=uipment are 93As far as possible onl( e=uipment a+ailable with ease should be selected3 Anless and until it is ascertained that new e=uipment will earn more than its cost or cab used in future also1 it should not be purchased3 <conomics should be wor2ed out3 #3Choice should be restricted to standard e=uipment1 special e=uipment should be selected if >ob >ustifies its selection )38opograph( conditions1 t(pe of soil1 e;isting approaches and road wor2ing conditions etc31 must be studied3 '37ess +ariet( of e=uipments should be used1 more +ariet( means more s2illed wor2ers1 more spare parts re=uirements and more production cost3 .3It is alwa(s better to purchase e=uipment manufactured in our own countr(3 8his will decrease the cost of repairs and down-time cost3 It will be beneficial to the nation also3 As far as possible e=uipment of same ma2e should be purchased3 53!ize of e=uipment should be made according to the amount of wor23 It is better to use more than one e=uipment of small size than using of one of large size3 :3-bsolescence of the e=uipment should not be o+erloo2ed3 63 <=uipment should be capable of doing more than one >ob1 but it should not be NCP#'/#.Page )
NICMAR PGP-CM
+ersatile3 438he technical and economic aspects should be anal(zed to select the e=uipment3
@ollowing aspects need detailed consideration at the selection stage 93!uitabilit( for the >ob with specific reference to climatic and other operating conditions 3#3!ize of the e=uipment )3!tandardization and +ariet( reduction '38(pe of prime mo+er .3Degree of utilization 53!uitabilit( of local condition :3Adaptabilit( 63 8echnical considerations3 8he choice of size of the e=uipment is indicated as either a minimum number of large size machines or se+eral units of medium/small size machines3 8echnical consideration for selection should include the following points3 93!trength #3Bibration !tabilit( )3Resistance to wear '3&eat Resistance .3Reliabilit( 53Maintainabilit( Equipment can be classified as: 93!tandard e=uipment #3special e=uipment It depends on e;tent of its use1 a+ailabilit( and cost3 -ne e=uipment standard for one ma( be special to other1 for e;ample a concrete mi;er of specific capacit( is a standard e=uipment for all most all the contactor whether class A or class D but NCP#'/#.Page '
NICMAR PGP-CM
cranes or concrete mi;er of +er( large capacit( are special to one whilst standard for other3 -ne definition for standard e=uipment is that which is easil( a+ailable in the mar2et3 It is eas( to repair1 spare parts are easil( a+ailable and can bed is posed off easil(3 Chilst special e=uipment manufactured on order and cannot be disposed off easil( and cannot be repaired b( all3 In general special e=uipment can be defined as an e=uipment manufactured for a single construction pro>ect or for a specific >ob3 Material Management 8he management of materials in pro>ect is different from that in an ongoing situation3 Most of the materials in pro>ects are bul2( and hea+(3 8he lead time for procurement of materials in most cases is usuall( much more38he principle of <-D has +er( limited applicabilit( in pro>ect situations3 Asuall( se=uential arri+al of material is desired3 8he demand of material in pro>ect is b( and large highl( deterministic 3 !ufficient care has the be ta2en in the selection of +endors has significant impact on the pro>ect performance3 8he demand of materials in a pro>ect situation is highl( deterministic3 8he gross re=uirement of +arious material is wor2ed out during the detailed pro>ect report stage3 8he primar( concern in material planning for pro>ect is that the cost of not meeting a demand is +er( high3 As it ma( lead to dela( in proper completion3 &ence the right time is the 2e( word in material planning for pro>ects3 8he capital re=uirements are to be planned in such a wa( that these are a+ailable at the site >ust before the erection/ installation of these3 8he demand of construction is 2nown as soon as their source re=uirement for the pro>ect is finalized3 8hese materials are normall( re=uired before the construction can start and are to be planned for a+ailabilit( prior to the construction phase of the pro>ect3 8he consumables are used throughout the pro>ect duration and the total re=uirements are 2nown3 &owe+er the consumption rate at different period is different but deterministic3 As the total number of consumable materials ma( run in to hundreds1 the anal(sis of aggregate demand pattern ma( be restricted to high consumption +alue materials onl(3 Procurement is of special significance in a pro>ect situation3 8he net effect of dela( in deli+er( and suppl( of inferior =ualit( of material is dela( in the completion of the pro>ect3 <conomic procurement is also +er( important as it is determinant for the +iabilit( of the pro>ect3 Eecause of these considerations +endor selection pla(s an important role3 8he consumables are standard materials and are usuall( a+ailable from man( sources3 -ccasionall( there is a scarcit( of some of these materials3 8he gross demand as well as the demand profile of these materials for the entire pro>ect duration are 2nown1 and it is desirable to enter into contracts with the suppliers3 Apart from these discussion on the technical details and price the negotiation can centre around the following issues -rdering !chedule 8o match with the pro>ect networ23 8he supplierFs networ2 for manufacture can also be discussed3 GPa(ment terms NCP#'/#.Page .
NICMAR PGP-CM
G7i=uidated damages GDualit( specifications and procedures for chec2ing =ualit( GInspection at different stages of manufacture at the supplierFs premises3 GIncorporation of design changes while the manufacturing is in progress3 GPerformance guarantee etc3 G8he in+entor( replenishment model shows the number of c(cles of replenishment during the usage period3 8he initial in+entor( of materials at the start of the wor2 consists of wor2ing stoc2 *D, and safet( stoc2 *!,3 Economic order Quantity: 8wo important decision to be ta2e while repetiti+e materials in+entor( are how much to order at one time and when to order this =uantit(1 or in other words1 to decide their order the =uantit( le+el and the reorder time c(cle so as to effect econom( in cost of purchasing and holding in+entor(3 8his economic order =uantit( *<-D, and the numbers of orders are determined mathematicall( as under In+entor( cost C " -rdering cost H In+entor( carr(ing cost C " Co 3 N H Ci 3 A/#N @or cost to be minimum dC/dN " Co I Ci 3 A/ # 3 N# " $ N# " Ci 3 A/# 3 Co And C " CoN H Ci A/#N " 9/#N *#CoN# H Ci A, " #Ci A/#N
8herefore 7east In+entor( cost " s=uare root o f #CoCiA Safety Stock: It is the floating stoc2 held to cater for changes in rate of consumption1 dela(s in deli+er( of materials from the agreed dates and under unforeseen causes1 so as to pre+ent stoc2-outs resulting in production hold-ups3 8he safet( stoc2 for a gi+en situation can be determined using statistical techni=ues3 Generall(1 a minimum safet( stoc2 can be ta2en as e=ual to consumption =uantit( in lead time period3 Lead ime:
It is defined as the total time re=uired for replenishment of an item of material from the time and indent is submitted to the purchased department1 to the time that read( for use materials are recei+ed at the pro>ect stoc2-(ard for storage or deli+ered at the site of wor23 NCP#'/#.Page 5
NICMAR PGP-CM
Reorder le!el: It is the le+el at which the stoc2 is ordered3 8his is determined b( adding assessed c consumption during the lead time period to the minimum stoc2 le+el 3
NCP#'/#.Page :
