NCP Material & Equipment Mgt

7/28/2019 NCP Material & Equipment Mgt

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ASSIGNMENT

NICMAR / SODE

MATERIALS AND EQUIPMENT

MANAGEMENT

Name of work: Constructing a new international airport 30 k.m.

away from a city. The project is to be implemented in phases.

Phase I: One strip of landing of 100 m width is to be constructed in

100days. The scope of work is as follows:

a) Cutting and Dozing of 100,000 cum of earth. Average height 0.75m.

b) Transportation of 20,000 cum of surplus earth from site to dumping place 3

k.m. away from site( including spreading) Filling of 80,000 kms in landing

strip.

c) Bringing in 3000cum of sand from 20k.m.(including spreading and leveling

at site)

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d) Procurement of 1, 50,000 litres of Bitumen. Duration of work 30days from

60th day of starting of work. Bitumen to be obtained from refinery at

Bongaigaon in Assam. Lead time up to site is 45 days. Storage facility

available at site 50,000 litres tank.

There are so many types of earth moving machines are available in the market.

Of which we use the equipments that are useful for our scope of work only.

Bulldozers the term bulldozer may be used in a broad sense to include both

a bulldozer and angle dozer. These machines may be further divided on the

basis of their mountings, in to crawler tractor or wheel tractor mounted. Based

on the method of raising and lowering the blade a bulldozer may be classified

as cable controlled or as hydraulically controlled. Bull dozers are mounted with

blades perpendicular to the direction of shovel while angle dozers are mounted

with blades at an angle with the direction of travel. The former push the earth

forward while the latter push it forward and to one side. Some blades may be

adjusted to permit their use of bulldozers or angle dozers. They may be used

from the start to the finish of such operations as:

- cleaning land timber and stumps

- operating up pilot roads through mountains and rough terrains

- moving earth for haul distances up to 100 m

- helping load tractor pull scrapers

- spreading earth fill

- cleaning construction sites to debris

- maintenance of haul roads

- cleaning the floors of borrow and quarry pits

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Scrapers:

Tractors pulled scrapers have established an important position in the earth

moving field. As they are self operating to the extent that they can load, haul and

discharge material they are not dependent on other equipment. If one of them

experiences a temporary breakdown it is not necessary to stop the job as would be

the case of machine which is used exclusively for loading earth into hauling units

for if the loader breaks down the entire job must stop until repairs can be made.

The self loading scrapers are available with capacities up to 38 cum or more. These

machines are the result of a compromise between the best loading and best

hauling machines and as must be expected at any composite machines they are

not superior to other equipment in both loading and hauling. Power shovels drag

lines and belt loaders usually will surpass them in loading only while trucks may

surpass them in hauling only especially when long, well maintained haul roads are

used. The development of High speed haul tractors has increased the economic

haul distance speed. Wheel type tractors have increased the economic haul

distance for the type of equipment up to 0.5 to 2.0 km.

Following equipments are used excavate earth and related materials and to lift

them frequently in construction operation.

The equipment includes the following machines:

- Power shovels

- Back hoes

- Draglines

- Clamshells and cranes

- Trenching machines

- Wheel mounted belt loaders

Power shovels are used for excavation and loading into hauling units

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Back hoes are used in excavation on natural surface. These are more rigid

than draglines and advantageously used on close range work

Clamshells are used mainly for lifting vertically and handling loose materials

such as sand, crushed stones in dams, pier foundation and sheet piling etc.

Trenching machines are either wheel or crawler type

Wheel excavators can cut weathered or broken rock.

Estimated productivity of 90ck, 0.9cum back hoe bucket

1. Bucket capacity (cum) - 0.9

2. Soil condition Average

3. Bucket fill factor 1.05

4. Actual Bucket Capacity 0.945Cum

5. Swing angle 180degrees

6. Standard cycle time - 15sec

7. Digging condition Deeper

8. Digging depth / Specified maximum digging depth Above 70%

9. Dumping condition Rather difficult

10. Conversion factor 1.5

11. Actual cycle time 22.5 sec

12. Operating conditions Average

13. Job efficiency 0.75

14. Hourly production (cum) 113

15. Number of hours of operation per day 12

16. Total production achieved per day 1362cum

17. Number of days of operation per month -25

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18. Total monthly production (Cum) 34020

19. Annual production (Cum) 48240

Estimated productivity of 180ck, 1.6cum back

hoe bucket




















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Estimated productivity of 180ck, 1.85cum back hoe

bucket




















Estimated productivity of 300ck, 2.7cum back hoe bucket




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11. Actual cycle time 36 sec









Take two 180ck, 1.6cum backhoe buckets and one 90ck, 0.9cum backhoe buckets.

For 100,000cum of earthwork excavation use two 180ck, 1.6cum backhoe buckets.

Number of days required to get the output 30

Number of hours required 360

Calculation of owning and operating cost of two 180ck excavators

Basic cost 45, 00,000INR

Life of equipment - 12000Hrs

Life of equipment 12years

Maintenance constant 50%

Depreciation cost 4500000 x 0.9/12000 = 337.50INR

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Fuel charges 18litres@38/- per litre = 684INR

Labour charges 25% x 684 = 171INR

Repair Charges Depreciation cost x Maintenance constant

337.5 x 50% = 168.25

Operator cost = 20INR

Helper cost = 15INR

Foreman cost = 7.5INR

Mechanic = 6INR

Watchman = 3INR

Total crew cost =51.5INR

Total usage cost = 51.5+168.25+171+684+337.50 =1412.3INR

Operating cost per hr = 4500000/12000 = 375INR

= 1412.3+375

=1787.3

= 1787INR (say)

Total cost of operation for excavation = 360 x 1787 = 643428INR

Owning cost = 4500000 +1412.3x360

= 4500000+508410

= 5008410INR

For two equipments it is equal to 10016820INR

Calculation of owning and operating cost of 90ck excavator

Basic cost 40, 00,000INR

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Life of equipment - 10000Hrs

Life of equipment 10years

Maintenance constant 50%

Depreciation cost 4000000 x 0.9/10000 = 360INR

Fuel charges 18litres@38/- per litre = 684INR

Labour charges 25% x 684 = 171INR

Repair Charges Depreciation cost x Maintenance constant

360 x 50% = 180

Operator cost = 20INR

Helper cost = 15INR

Foreman cost = 7.5INR

Mechanic = 6INR

Watchman = 3INR

Total crew cost =51.5INR

Total usage cost = 51.5+180+171+684+360 =1446.5INR

Operating cost per hr = 4000000/10000 = 400INR

= 1446.5+400

=1846.5

= 1847INR (say)

Three types of records are maintained at site and they are

i) Progress records

ii) Work output records of individual machines and team of machines

iii) Equipment records

Progress records:

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Records of progress may be kept in a variety of forms, but the method adopted

should be as simple as possible, and to be of real value, must allow for immediate

comparison with planned programme and show at a glance, the actual break up

made, often on percentage basis.

Suitable methods are

i) Work programme as progress records

ii) Bar graph progress chart

iii) Line graphs

iv) Pictorial records

Work output records:

Records of actual output of individual machines and if desired, of team of

machines, will not only be useful on the projects itself to help in analyzing any

causes of delay in progress of work but will prove of great value for further

planning and estimating. To enable these records to be compiled, plant

supervisors reports will be necessary.

Plant supervisors reports:

Each plant supervisor should be required to complete shift report at the end of

each shift, showing relevant information about the machines which have been

under his control during the shift. The report should not be confused with plant

operators daily log which is mainly concerned with servicing and fuel consumption.

Typical items to be entered on plant supervisors report for each machine are:

i) Task on which employed

ii) Total work carried out e.g. number of trips performed, total mileage or

number of vehicles loaded , depending on type of task

iii) Number of minutes worked per hour

iv) Servicing periods

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v) Remarks on delay and waiting times with reasons.

Basic record of equipment maintained

i) Log book

ii) Daily / Monthly working data

iii) History book

Log book:

The log book is to utilized for two purposes

a) For a technical control to evaluate how the machine is performing, and

b) For getting the Plant hours performance classified by works

To determine performance, the total plant hours put in by a machine must be

known and causes of trouble should be classified. The log book records the

consumption of fuels and lubricants, since the performance of the machine can be

judged readily from these figures. It records the work on which the machine was

employed indicating the officer on whose requisition the machines was utilized.

Daily / monthly working data:

Log book also gives record of utilization of machinery. Other data such as sickness,

idleness etc. is not readily available in logbook. The data is equally important to

indicated performance of machine. For this purpose the data is to be maintained in

the form of daily working machinery. Monthly abstract should be prepared.

Maintenance registers:

The maintenance register for the following should be maintained:

i) Daily maintenance

ii) Weekly maintenance

iii) 100 to 175 hours maintenance

iv) 250 hours maintenance

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v) 500 hours maintenance

vi) 1000 hours maintenance

vii) 2000 hours maintenance

Supervision:

The purpose of supervision is not only to see that work is carried out correctly to

specifications laid down and the machines are properly used and output

maintained at consistently high level but also to foresee difficulties and likely

bottlenecks which may reduce output and to take steps to obstacle them before

they occur.

Supervisors responsibility to:

i) Ensure that all the concerned under his command are clear on their

task.

ii) See that machines are used to best advantage and operators take their

task correctly.

iii) Ensure that the work is properly done to the specification laid down.

iv) Take early steps to deal with difficulties in order to assist the operators

to maintain their output where difficulties develop which he cannot deal

with satisfactorily from his own resources, report them without delay to

next supervisor, with the recommendation as to how they can best be

overcome.

v) Always be thinking ahead to foresee likely difficulties and bottlenecks to

the progress of work before they occur so that steps can be taken in

time to prevent them of failing this to reduce this adverse effect on out-

put.

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Transportation of 20,000 cum of surplus earth from site to dumping place 3 k.m.

away from site (including spreading)

Calculation of Disposal of earth for tippers

i) Lead for 3+3 = 6k.m.

ii) Average speed = 25kmph

iii) Loading time = 5.00mins

iv) Travel time = (6/25)x60 = 14.40mins

v) Unloading time = 4.00mins

vi) Idle time = 2.00mins

vii) Time per trip = 5+14.40+4+2 = 25.40mins

viii) Add for break down 10% = 2.54mins

ix) Total time per trip = 25.4+2.54 = 27.94

x) Working time per day 16hours a day = 16 x 60 = 960mins

xi) Number of trips per day per vehicle = 960/27.94 = 34.35 = 35(say)

xii) Quantity per vehicle per day = 35 x4 = 140cum

xiii) Distance travelling per day = 6x35 = 210k.m.

xiv) Quantity per vehicle per month(assuming 25days per month) = 140x25

=3500cum

xv) Distance travelled per month = 210x25 = 5250k.m.

For the disposal of 20,000cum of earth we need 20,000/3500 = 5.71= (6 say)

6no. of tippers are enough to dispose the earth to the dumping yard.

Calculation of Bringing of Sand for tippers

i) Lead for 20+20 = 40k.m.

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ii) Average speed = 25kmph

iii) Loading time = 5.00mins

iv) Travel time = (40/25)x60x2 = 192mins

v) Unloading time = 4.00mins

vi) Idle time = 2.00mins

vii) Time per trip = 5+192+4+2 = 213mins

viii) Add for break down 10% = 21.3mins

ix) Total time per trip = 213+21.3 = 234.3

x) Working time per day 16hours a day = 16 x 60 = 960mins

xi) Number of trips per day per vehicle = 960/234.3 = 4.09 = 4(say)

xii) Quantity per vehicle per day = 4 x4 = 16cum

xiii) Distance travelling per day = 40x4 = 160k.m.

xiv) Quantity per vehicle per month(assuming 25days per month) = 16x25

=400cum

xv) Distance travelled per month = 160x25 = 4000k.m.

For bringing of 3000cum of sand from 20k.m. we need 3000/400 =7.25(8say)

8no. of vehicles are required to get the 3000cum of sand with 20k.m. lead.

Procurement of 150,000 litres of bitumen from refinery which is located

Bonagaigaon in Assam.

Lead time up to site is 45days.

Calculation of Economic order of quantity for Bitumen:

Take Wilson Harris square root formula

The quantity of order corresponding to the frequency is known as Economic order

of quantity. The economic order quantity or lot size can be war analytically. The

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relation between various parameters was developed by RH Wilson and F. Harris

and is known as Wilson Harris Square Root Formula.

The relation is worked out below and is based on assumptions.

a. The demand over the period of the cycle (normally a year) constant and is

known in advance.

b. Consumption of material occurs at the uniform rate.

c. The price of the material is independent of the order.

d. There is no lead time in the replenishment.

Let

A: be the annual demand in terms of units

Q: is the lot size ordered at a time in units

P: Price of the material in terms of

H: Annual inventory carrying / holding cost expressed in Rs. per Rupee of the

inventory

S: Ordering cost (i.e. cost of placing one order) in Rs.

Since the stock in depleted at uniform rate over the cycle period, inventory

carrying cost or holding cost can be the cost over the average stock.

As Q increases the number of orders hence ordering costs reduce, but inventory

carrying costs increase and vice-a-versa. The economic lot size will have to

balance the two costs of opposing nature.

If Q is the lot size the average inventory will be Q/2

Inventory carrying cost will be

Q/2 x p x h

Number of orders over a year = A/ Q

Total Ordering costs = A/Q x S

Thus the total cost T = Q x p x h/2 + Ax S/Q

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We have to find the most economic order quantity for which T is minimum.

dT /dQ should be equated to zero.

dT/ dQ = p x h /2 = A x S/Q^2 = 0

A x s / Q^2 = p x h/2

Q^2 / A x S = 2/ p x h

Therefore Q = Square root of (2x A x S/p x h)

Assume 300 working days in a year

Annual consumption 300 x 3333litre a day = 1000000 litres

Inventory carrying cost Rs. 4 per litre i.e. 20Rs. Inventory

As we need 50000 litres per order because we have only the capacity of

50000litres of storage capacity and the lead time is 45 days from the refinery to

site office. We place 3 orders of 15 days duration from the start of the work. By

which we can get the bitumen by 45days, 60th day and 75th day the total quantity

of bitumen. On 60th day Bitumen work is to be started. Bitumen is planned per day

is 3500litres. Within 15 days 50000litres of bitumen can be consumed. The storage

capacity will be available for another 50000 litres. As the excavation progresses

and the site is available for runway works. Consumption bitumen increases and by

that bitumen procurement from the refinery to site storage cann be made. The

planned quantity of utilization of bitumen can be done within the stipulated

duration of 100days. During storage of bitumen the temperature of 100 degree

Celsius is maintained. Maintaining the boiling temperature of bitumen is important

site storage tank. So the planned schedule is going to be maintained at the site.

Conclusion:

The equipment and materials management can be achieved with

perfect planning and execution. Spare parts for the equipment

should be made available for emergency repair works

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Bibliography:

1. Materials and Equipment management - NICMAR

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