ROAD & BRIDGE

CONSTRUCTION EQUIPMENT

JANUARY ,2012 1

Satya Narayan ShahB.Sc. In Mechanical Engineering (India)

MS in Manufacturing Engineering & Management (UK)

Generally, we use the Equipment

when a job requires -

1. SPEED

2. QUALITY

3. ECONOMY

4. EMERGENCY/DISASTER

MANAGEMENT

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Extent of Mechanization• Manpower- Availability, Job requirement, Human factors

etc.• Completion Period- less completion period more

mechanization.• Nature of Work- beyond control of manpower, weather,

topography, work handling capacity etc.• Availability of Money- needs high initial investment.• Availability of Equipment- Import of equipment,

availability of spares, after sales service etc.• Social Objects of the Project- employment opportunity,

labour intensive, state policy etc. • Labour Relation- Labour unrest, strikes, demands,

absentees etc.• Quality & performance- Quality requirement

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MAJOR CONSTRUCTION EQUIPMENT

USED IN CONSTRUCTION INDUSTRIES

Pneumatic/Hydraulic Tools Air Compressor/ Hydraulic Pump

Rock Drill/Jack Hammer/Other Drills

Concrete Breaker

Asphalt Cutter

Impact Wrenches/Nail Driver

Grinder

Concrete Vibrator

Circular saw/ Chain Saw

Road Broom4

MAJOR CONSTRUCTION EQUIPMENT

USED IN CONSTRUCTION INDUSTRIES

Aggregate Producer Rock Crushers, Screen, and Conveyors

Central Mix Plant (Asphalt), (Batch Plant/Continuous Mix Plant)

Bitumen Decanter, Bitumen Heater

Bitumen Distributor

Portable Mix Plant

Pavers (Asphalt/Concrete)

Aggregate Spreader

Concrete Mixers/Concrete Batch Plant

Concrete Vibrator 5

MAJOR CONSTRUCTION EQUIPMENT

USED IN CONSTRUCTION INDUSTRIES

Earth Moving Equipment Dozers (Track/Wheel)

Loader (Track/Wheel)

Excavators (Backhoe/Shovel ) (Track/Wheel)

Dragline

Bucket wheel excavator

Scrapers

Grader

Milling Machine

Hauler (Off highway haulers, Tipping

Trucks, Mini Dumpers)6

MAJOR CONSTRUCTION EQUIPMENT

USED IN CONSTRUCTION INDUSTRIES

Compaction Equipment

Sheep Foot Rollers/Tamping

Rollers

Steel Wheel Static Roller

Steel Wheel Vibrating Roller

Pneumatic roller

Plate Compactor/Rammer

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MAJOR CONSTRUCTION EQUIPMENT

USED IN CONSTRUCTION INDUSTRIES

Ancillary Equipment Water Distributor

Rotary Tiller Mixer

Portable Electric Generator

Welding Generator

Pile Driver

Water Pump

Boring Rig

Crane/ Fork Lift

Flat Bed Truck

Low Bed Transporter

Road Broom

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Dozers

DOZERS: Introduction• Earlier, the Dozers were developed on farm tractors

by an American company (Holt ManufacturingCompany) around in 1904 which is later becameCaterpillar Inc.

• These days, Dozer has become one of the mostrepresentative strong construction machinery.

• Also commonly known as Bulldozer/ Tractor.

• Dozer is a self-propelled unit that are designed toprovide high tractive power for drawbar work.

• High stability at work.

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Dozer: Component arrangement

Blade

This is working tools use to push

earth cutting and leveling the

ground

Power Train

This is transmit

Engine power to

final drive of the

machine

Undercarriage

This is the feet of the

machine that use to move

/ turn machine

Cabin

This consist

operator’s seat and

control panel and

joysticks from where

machine is operated. Ripper

This is an

attachment

tools that use

to dig hard

surfaces

Engine

This is the primover

that provide power to

run/ work the machine.

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]

• Upper Parts

– Engine

– Transmission Power train

– Cabin / Control Panel

• Undercarriage

– Track Frame

– Sprocket/ Idler

– Track Chain

– Track Roller

– Carrier Roller

• Hull / Body Frame

Dozers: Main Parts / Systems

(Track Dozer)

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Dozers: Main Parts / Systems

(Track Dozer)

• Attachments

– Front mounted (Blades, Shovels etc.)

– Rear mounted (Ripper, Winch etc.)

• Hydraulic System

– (Pump/Lift & Tilt Cylinder/Hose pipes

• Electrical System

– (Battery/ Starter/Dynamo/Lighting)

• Braking and Steering system

• Control System

– (Control valves, Control panel, Gauges/Sensors)

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APPLICATIONS OF DOZERTypical Applications are:

–Dozing / Pushing materials–Sidehill Cut–Backfilling–Ripping–Land clearing–Ditching–Towing/Pushing other piece of construction

equipment–Assisting scraper in loading

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DOZING/

LEVELING

PUSHING

MATERIALS

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ASSITING SCAPERS

RIPPING ROCKS

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LAND CLEARING

REMOVING ROOTS 17

TYPES OF DOZERS1. Crawler / Track Type 2. Wheel Type

Track Dozer

Wheel Dozer

- Can work on variety of soil surface

- Can work over almost all terrain

- Can work on soft ground and mud-stick

surfaces.

- Exert low ground pressure

- Good for short working distance

- Slow return speed

- Can push large blade load

- Good on firm soil and concrete surface

- Best for level and downhill work

- Can not work on soft ground and mud-

stick surfaces.

- Exert high ground pressure

- Good for long working distance

- Fast return speed

- Can only push moderate blade load18

Crawler or Track Dozer• Have a continuous TRACK of linked

shoes that moves in the horizontalplane across fixed rollers.

• Track passes over the verticallymounted SPROKET at rear and IDLERWHEEL at front.

• The SPROKET (mounted on finaldrive), pass on the power to the trackchain that impart the forward orbackward motion.

• ROLLERS (Track and Carrier) supportthe Track chain.

• The IDLER WHEEL is mounted on arecoil device (Mostly Recoil Spring)for adjusting track tension andabsorbing shock.

Breaking & Steering Actions

are combined

Steering clutch used to turn

one track and stop other-side

track assisting machine to

steer effectively.

Applying equal pressure on

both sides steering clutch

moves machine straight

forward of reverse direction.

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Wheel Dozers

• The front frame and rear frame isconnected by the vertical centralpivot.

• Wheels are mounted on front andrear axles.

• Power from final drive exert rimpullforce that turns the wheels andmoves machine in forward or reversedirection.

• Traction force can be improved byproper tyre selection. Wider tyresprovide greater contact area andincrease flotation.

• Larger sized tyre will reducedeveloped rimpull.

Have all powered four

Wheel Drive.

Breaking action on wheels

as in Vehicle.

Steering achieved by

Articulation between Front

and Rear portion of the

Equipment

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Dozer’s BLADE• BLADE is the main working tools

(Implements) mounted on “C”frame in front of the machineperpendicular to direction oftravel which PUSH (cut/ shear/rolls) earth cutting in forwarddirection.

• In the case of ANGLE DOZERblade is mounted on “C” frameat a set angle with direction oftravel and push materialsforward at one side.

BLADE C-Frame

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BLADE Adjustments: TiltingTILTING:

• Either end of the Blade is raised or lowered in the Vertical Plane of the blade.

• Enables the concentration of dozer driving power on the limited portion of the blade’s length

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BLADE Adjustments: PitchingPITCHING:

• The movement of the top of the blade toward and away from the Dozer.

• Allow operator to varies the angle of attack of the cutting edge as per cutting materials requirement.

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BLADE Adjustments: Angling• Turning the blade so that it is not

perpendicular to the direction of the dozer’stravel.

• Angling causes the pushed material to roll ofthe TRAILING END of the blade called sidecasting.

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BLADE TYPES• Straight blades “S”: The straight blade is designed for short-and medium-distance passes,

such as backfilling, grading, and spreading fill material. These blades have no curvature in their length and are mounted in a fixed position, perpendicular to the dozer’s line of travel.

• Angle blades “A”: An angle blade is wider by 1-2ft than an S blade. It can be angled up to a maximum of 250 left or right of perpendicular to the dozer, or used as a straight blade. An angle blade can be tilted, but because it is attached to the dozer by a C- frame mount, it cannot be pitched. The angel blade is very effective for side casting material particularly for backfilling or making side hill cuts.

• Universal blades “U”: This blade is wider than a straight blade and the outside edges are canted forward about 250. The canting of the edges reduces the spillage of loose material making the U blade efficient for moving large loads over long distances. The hp/ft ratio is lower for the U than the S blade mounted on a similar dozer.

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• Semi –U blades “SU”: This blade combines the characteristics of the S- and U- blade designs. It has increased capacity by the addition of short wings.

• Cushion blades “C”: Cushion blades are mounted on large dozers that are used primarily for push-loading scrapers. The C blade is shorter than the S blade so as to avoid pushing the blade into and cutting the rear tires of the scraper while push-loading.

Hydraulic Excavators

Hydraulic ExcavatorHydraulic Excavator is the most commonlyused construction machine. it has bucketwith specified volumetric capacity.

Hydraulic power is the key utility to operatethe hydraulic excavators.

It can work at very high gradient anddifficult terrain.

With various front attachments, it can beused for diversified purposes.

Most excavators are mounted on track base,but smaller model may be mounted onwheels base.

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Hydraulic Excavator: Main Parts• A hydraulic Excavator consists THREE major parts

1. Work Equipment

This part consist

working tools for

digging and loading

2. Upper Structure

This part consist engine,

cabin and holds components

such as operator’s seat

controlling joysticks and

monitoring gauges

3. Undercarriage

This part consist Crawler/

track chain or Wheel for

moving machine on the

ground.28

Upper Structure: Cabin Interior

Depending on

moving direction

of control Lever/

Pedals Machine

can move

straight or turn

left or right.

Depending on moving direction of control Joystick Boom, Arm or Bucket can

be moved for doing work or machine can swing to require degree of rotation

n InteriorCabi

Travel LeversMachine monitoring units

(Temp., Press. Gauges)

Work equipment

control Joystick

Engine starting

switch

Fuel gauge

Lights / Other

switches

Travel

Pedals

Work equipment

control Joystick

Operator’s

seat

Arm/Swing Controls (Left Joystick)

move forward and backward to move Arm out and in

move left and right to control direction of swing

Boom/Bucket Controls (Right Joystick)

move forward and backward to lower and raise boom

move left and right to control bucket curl and dump

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Excavators: Swing mechanism

Pinion Outer race

Inner race

Ball bearings

SWING CIRCLE

The outer race fixed at upper structure

turns with the “Pinion” that spins along with

the inner race fixed at the lower structure.

The part between the outer race and the

inner race turns smoothly on the ball

bearings.

This part enables an

hydraulic excavator to

turn aroundStick/Swing Controls (Left Joystick)

move forward and backward to move stick out

and in

move left and right to control direction of swing

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Lower Structure:UndercarriageMost are Crawler/ Track type.

Compared to the Wheel type, the

Crawler type has more part

touching the ground. Which

enables them to work on muddy

surface where Wheel type can not

be used.

WHEEL

(TYRE)

Seen from

the sides

Seen from the

underneath

CRAWLER /

TRACK

The part touching the

ground surface

Wheel type excavator

make use of supports/

Stabilizers during work.

Can also be fitted

with dozing blade

. (Optional)

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Hydraulic Excavators: How it Works ?

Arm Cylinder Control Valves

Hydraulic

Pump

Engine

Hydraulic Oil Tank

Swing Motor

Travel Motors

Boom

Cylinder

Bucket

Cylinder

Hydraulic Power is the key utility to operate all Hydraulic Excavators

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Excavators : Types• Based on mounting type; they are classified as:

1. Crawler or Track type

2. Wheel type

Both front SHOVEL type or HOE type Excavator can be

mounted on either on a Crawler or a Wheel tractor base.

• Based on types of Bucket or digging motion of theyare classified as:

1. Shovel type

2. Hoe type

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Hydraulic Excavator: Front Shovel

• An upward motion unit is know as“front shovel”

• Hydraulic front Shovel excavators areused mainly for hard digging abovetrack level and for loading to haulingunits.

• A shovel develops breakout force bycrowding material away from themachine.

• The boom of a shovel swings upwardto load; so the machine requires amaterial face above the ground level

Basic Features:

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Hydraulic Excavator: Hoe

• A downward arc unit is classified asHoe

• Hydraulic Hoe excavators are usedprimarily to excavate below theground level on which machine rest

• It develops excavation breakout forceby pulling the bucket towards themachine and curling the bucketinward.

• The downward swing of a hoe dictatesusage for excavating below the groundlevel at which machine rest

Basic Features:

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Hydraulic Excavator• The hydraulic excavators are fully hydraulically

control machine which provides:

– Faster cycle time

– Less noisy

– Smoothness and ease of operation

– High overall efficiency

– Greater accuracy and precision

• It is a versatile machine that can be used foralmost all kind of applications.

• A quick coupler enables to quick change withdifferent type attachments and perform a varietyof tasks in rapid succession

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Hydraulic Excavator: Application• Hydraulic hoe has evolved from a single purpose excavating

machine into a versatile multipurpose tool.

• It is a versatile machine that can be used for almost all kind ofapplications.

• Typical general applications are:– Digging below or above the ground level

– Canal/ Trench excavating and pipe laying

– Loading hauling units

– Lifting construction materials

• A quick coupler enables the hoe to change attachments andperform a variety of tasks in rapid succession. Some commonattachments are:– Hydraulic breaker - Crane

– Clamshell - Rock driller

– Impact hammer - Demolition jaw

– Cutters - Land clearing grapple

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Typical Applications

Attachments

Handling Scrap materialsBuilding demolishing

Various types of attachments

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Factor affecting production• Actual production of a shovel is affected by

the following factors:

– Class of material

– Height of cut

– Angle of swing

– Size of hauling units

– Operator skill

– Physical condition of the shovel

Production efficiency ranges from 30 to 45

min per hour

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LOADERS

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LOADERS• Also known as a front end loader, bucket

loader, scoop loader, or shovel, the front loader is a type of tractor that is normally wheeled or Tracked.

• Use a wide square tilting bucket on the end of movable arms to lift and move material around.

• The loader assembly may be a removable attachment or permanently mounted.

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LOADERS• The deep bucket on the front loader can

normally store around 3 – 6 cubic meters, as the bucket capacity.

• Loaders aren’t classified as excavating machinery, as their primary purpose is to handle the loose materials.

• Front loaders are used to transport building materials such as pipe, bricks, metal bars, and digging tools.

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LOADERS

• Front loaders are also very useful for snow removal as well.

• Unlike the bulldozer, most loaders are wheeled and not tracked.

• The wheels will provide better mobility and speed and won’t damage paved roads.

• Articulated steering allows the front axle to be solid, therefore allowing it to carry a heavier weight and gives a reduced turn in radius.

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LOADER BUCKETS

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46

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BACKHOE LOADER MAJOR COMPONENTS

LOADER CONTROLS

BATTERY

ENGINE OIL DIPSTICK

DOOR

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DIPPER ARM

STABILISER LEG

MAJOR APPLICATIONS OF BACK-HOE LOADER

• Clam shovel allows you to load, dig, grab, grade, doze and spread without changing attachments.

• Truck loading

• Levelling and spreading large piles

• Stripping and levelling with the loader

• Capable of performing all most all the activities like excavators

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Dragline

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Draglines are amongst the largest mobile

equipment ever built on land, and weigh in the

vicinity of 2000 metric tonnes, though specimens

weighing up to 13,000 metric tonnes have also

been constructed.•

A dragline excavator is a piece of heavy equipment used

in civil engineering and surface mining

• Civil engineering

– the smaller types are used for road, port

construction, and as pile driving rigs.

• Mining

– The larger types are used in strip-mining

operations to move overburden above coal,

and for tar-sand mining.

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Dragline excavator

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Major Parts of Dragline

• Dragline bucket system consists

– a large bucket

– a boom (a large truss-like structure)

– Wire ropes

• hoist rope

• Dragrope

By skillful manoeuvre of the hoist and the

dragropes the bucket is controlled for

various operations. 54

Dragline excavator with pile

driver attachment.

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Bucket wheel excavator

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Bucket-wheel excavators

• Construction/mining equipment used in

surface mining and mechanical

engineering/civil engineering.

• To act as a continuous digging machine in

large-scale open pit mining operations.

• Use of a large wheel consisting of a

continuous pattern of buckets used to scoop

material as the wheel turns.

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Scrapers

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Scrapers• Single or tandem engine, tandem engine

push-pull.

• Preferred for:

– Completing large projects, including road

construction, airports, dams, and large-scale

residential and commercial development

– Moving high volumes of material under short time

constraints

– Executing short to long loaded hauls from load to

dump areas

– Traveling at high speed along well-developed

haul roads 59

GRADER STRUCTURES60

GRADER STRUCTURES61

Major Part of A Grader62

Prime Mover (Engine) Transmission System

Tandem Drive Hydraulic System

Operator’s Cabin Moldboard

Circle Assembly Draw Bar

Steering System Blade

Main Frame Attachments

ATTACHMENTSTo add additional versatility to the motor

grader with attachments designed just for special application.

Increases the scope of works.

Best use of investment.

Reduce Idle time of equipment

Quality products

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ATTACHMENTS

Dozer blade

The front-mounted Dozer Blade is used for bulldozing jobs such as displacing gravel piles, small stump removal, fallen rock clearance from road shoulders and other blading applications where access with the grader moldboard may be difficult.

Parallel linkage maintains blade angle at all depth. Boxed beam blade support provides excellent blade rigidity. Offers full hydraulic control using lever.

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ATTACHMENTS

Ripper/Scarifier

The Ripper/Scarifier mounts to the rear frame and is designed for breaking up asphalt or other hard-pack aggregates prior to blading.

Effective for uniform mixing of coarse and fine material, improving compaction of road surfaces.

Parallel tooth ensures consistent ripping depth throughout the working range and provides consistent material break up/mixing of aggregates.

Full hydraulic control.

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ATTACHMENTS

Front mounted Scarifier

The Front Mounted Scarifier mounts to the nose plate and is designed to break up compacted material, asphalt and rocky subgrade.

Simplifies scarifying applications against curbs, walls or near other obstacles.

Parallel action ensures even penetration of all teeth at all working depths.

V-shaped design permits efficient material flow.

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ATTACHMENTS

Mid -mount Scarifier

The Mid Mount Scarifier mounts behind the front axle and is designed to break up compacted material, asphalt and rocky subgrade.

Provides optimum cutting capability and excellent visibility to the attachment.

Tilt adjustment accommodates various working applications.

Hydraulic control using lever.

V-shaped design permits efficient material flow.

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ATTACHMENTS BLADE BOWL

Consists of two sideboards, a spreader bar, cutting edge and a bottomless blade bowl.

This attachment is used in rough earthen roads where hole are to be filled.

Cutting edge cuts the high spots at the same time the material is stored in the bowl with the help of moldboard and sideboards.

The material is filled when the holes comes through.

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ATTACHMENTS

Push block

The Push Block is mounted to the grader nose plate and performs two basic functions: as a counterweight to maintain grader balance when a rear Ripper/Scarifier is installed, and as a push point in applications where a grader is used as a push vehicle.

Extends beyond the front tires to provide ample clearance during pushing.

Can be easily mounted and removed to facilitate the use of other front mounted attachments.

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ATTACHMENTS

BLADE STABILIZER

Hydraulically operated skid plate

Mounted behind the moldboard.

Dampens the blade when rhythmic bounce is created due to hard cut.

Serves as a third point of suspension.

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ATTACHMENTS SLOPER

Basically two kinds- for (a) shoulder works and (b) ditch works.

(a) Extension of the normal blade to reach over a berm or embankment for cutting

(b) Extension to reach the ditch to clean and shape.

Operator works from the road.

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ATTACHMENTS ELEVATING GRADER

This attachment with a cutting disc, material is fed into conveyor.

The material either loaded to a truck or spread over the ground.

Used to elevate the road bed, clean and reestablish ditches, strip material from road side berm, de-silting irrigation cannel etc.

Highly productive.

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ATTACHMENTS

GRADER SCRAPER

Consists of bowl, apron, and ejector, all hydraulically operated.

Cuts the material, store in the bowl and dump it to required site.

Can cut “V” and flat bottom ditches built farm terraces, construct and maintain banks, dams, rebuild roads, clean ditches, and culverts, cuts slopes, remove snow.

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ATTACHMENTS

DISC HARROW

Rear mounted harrow

Series of Circular blades are banked together and mounted .

Loosens, pulverizes and blends material.

Generally used in combination with Scarifier.

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GRADER APPLICATIONSGraders may be used for:

a) Cutting drainsb) Bank batteringc) Forming roadsd) Levellinge) Mixing materialsf) Scarifyingg) Light rippingh) Windrowingi) Minor excavationsj) Snow Plowk) Trench Cutter & Filler

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Normal Blade Positions76

Covering Large Area 77

Spreading Materials78

Blade Pitch79

Sloping High Bank80

Grading in Reverse81

Ditching or Ditch Cleaning82

Sloping During Ditch Cutting83

Backfill84

1800

PURPOSE OF COMPACTIONTo develop the potential strength of a

material as required by the intended use

To create state of volumetric stability for the ultimate state to which the material will be subjected.

To produce a minimum permeability of the material in its final in-place state.

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The amount of compaction is influenced by the following factors. The moisture content of the soil

The nature of the soil (Grain size distribution and physical properties)

Depth of lift

Climatic conditions

The type and amount of compacting effort

Type of equipment

Among above factors, the last two factors are related to the compacting equipment.

87

Compacting effort refers to the method employed by equipment to impart energy into the soil to achieve required compactions. The equipment are designed to use one or a combination the following types of compactive efforts to the soil to achieve ultimate result of compaction.

Actions required for compaction

Static Weight (or Pressure)

Crushing

Kneading Action

Impact (or Sharp Blow)

Vibration (or Shaking)

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Types of Compaction EquipmentCompactors can be grouped in the following types: -

Smooth Steel Drum Rollers Sheep Foot Rollers Grid or Mesh Rollers Tamping Rollers Towed tamping Vibratory tamping

Vibrating RollersMulti Tyred Pneumatic Rollers Plate Compactors Vibrating Compactors

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SMOOTH STEEL DRUM90

Smooth Steel Drum

Oldest form of mechanical compaction.

Concrete Drums are also used for small works.

Single drum or multi drums.

Available up to 14 to 20 ton

Towed type to Self propelled.

Generally used where crushing effect is required.

Good for surface finishing.

Lift up to 12” can be compacted efficiently.

Compacting Weight can be increased or decreased by varying the ballast.

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Smooth Steel Drum Front wheel is on dead axle used for steering. Rear wheels are powered. Power is transferred from engine through

clutch/torque converter shaft and gears. Most commonly used is 3-axle tandem roller with

weight transferring device. Differential locking arrangement.

It is best used for base courses of crushed stone.

Not suitable for surface dressing.

Bridging characteristic.

Not possible to prevent bow-waving. (tendency to create wave of asphalt in the front roll)

A steel roller is basically slow.

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SHEEP FOOT ROLLERS93

SHEEP FOOT ROLLERS 40 to 72 inches dia drum ranging in weight 3 to 30 Tons.

7 to 17 inches long cylindrical pads are welded over the circumference of the drum.

Generally they are towed type.

They are intended to shear and knead the soil.

Suitable for compacting all fine-grain materials.

Not suitable for use on non-cohesive granular materials.

Low speed from 6.4 to 9.6 km/hr.

Efficient for silt-to-clay soils

Nos. of passes depend on the lift; usually 6 to 10 passes will be needed to compact a 20 cm. clay lift.

The roller becomes lighter as the density of the soil increases. .

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TAMPING ROLLERS95

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TAMPING ROLLERS Similar to Sheep foot rollers. Shape and size of the foot is different they

are tapered so that the entry and exit are clean. Fluffing of soil is avoided.Working speed is higher than sheep foot

roller (8-12 mph) .

Handle nearly all soils.Not suitable for clean sand. Suitable to compact 12” to 18” lift.There are towed and self propelled. Static and vibratory.

GRID OR MESH ROLLERS97

GRID OR MESH ROLLERSThe roll surface is made of cast steel with grid or mesh. They are particularly effective on granular soils to compact 6 to 8 inches to up to 18 inches on rock fills. It is an excellent compaction machine for rock fills as it crushes the rocks with the help of mesh and crushed particles fill the voids as it moves forward.

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Vibratory Rollers99

Vibratory Rollers Eccentric Shaft creates Vibration due to centrifugal force. Vibration has two measurements– amplitude, which is the

measurement of the movement, or throw, and frequency, which is the rate of movement, or number of Vibrations (oscillations).

The amplitude controls the effective area, or depth to which the vibration is transmitted into the soil, while the frequency determines the number of blows or oscillations that are transmitted in a period of time.

Vibration creates impact forces, and these forces result in greater compacting power than an equivalent static load.

Vibrating drum rollers are actuated by an eccentric shaft that produces the vibratory action.

The Vibrating mass (drum) is always isolated from the main frame of the roller.

Vibrations normally vary from 1,000 to 5,000 per min.

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Vibratory RollersDynamic force created by a vibrator’s mechanism can be calculated from the following

calculation;

F=0.00034WRN2

Where, F = Dynamic force in poundsW = Weight of eccentric mass in poundsR = Radius from center of eccentric mass to center of rotation in feetN = Rotation speed in revolutions per minute

From the above formula, it is seen that the dynamic force increases with the square of the frequency. Dynamic force combining with the static force of the roller provides the total striking force to the soil.Benford Pedestrian Single drum vibratory roller owned by the DOR provides 920 Kg of centrifugal force at 3900 rpm and 65 cycles per second. This centrifugal force further provides 7,480 Kgs. of striking force at contact soil.

A vibratory compaction has the following advantages over the conventional compaction.

Light weight and smaller towing unit. Better mobility Less expensive Effective to greater depths.

101

Vibratory Rollers (cont……)

These rollers are gaining popularity due to versatile usages.

Very wide in type, size and compacting width, means of providing vibrations.

Single drum or dual drum.

Effective on Granular material (Rock to fine sand)

Semi cohesive material

High lift

Smooth Drum / Padded Drum

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Small Walk Behind Rollers

Width in the range 24 to 38 inches.

Suitable for

Trench work

Building Foundation

for working in confined area.

Vibrating Rollers are also available /modified as per the work site conditions. e.g. drum extend beyond the rollers body , drums used as attachment to other equipment

Remote control Rollers available to work in deep trench.

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Multi tyred Pneumatic Rollers104

Multi tyred Pneumatic Rollers Available upto 200 ton gross weight. Surface rollers using Principle of kneading Action to effect

compaction below the surface. Front and Rear wheels are so placed to cover the complete

surface. Weight of the roller can be varied with the help of using

ballast. Two tandem axles with 4-5 wheels. for uniform compaction, Wheels oscillate to follow

surface contour Wheels may be mounted slightly out of line with axle

weaving action - WOOBY WHEEL- more kneading action. Compactive effort is a product of wheel load, tyre size and tyre

inflation pressure. The contact area increases when the inflation pressure decreases. Tyre Pressure- must be varied as per the soil type; on clay 90 psi can

compact 14” where as 150 psi can compact 9” only. Larger Dia wheel is easier to move than small dia wheel. Self propelled or towed type

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Plate Compactors/Rammers106

Plate Compactors/RammersLift thickness is small ( 3 to 4 Inches).Moisture content is carefully controlled.Coverage is sufficient.Suitable for small works.For compaction of soils and asphalt

concrete.Where large units are not practical.Remote controlled compactors are

available.

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Vibrating Compactors108

SELECTION OF EQUIPMENT• Suitability for job condition-climate, working condition

• Size of the equipment- matching with production target, matching with other units

• Standardization- same type and size of the equipment in a project, reduces spares reserve.

• Availability of equipment- easily available,

• Availability of spare parts- after sales service, spares inventory in a project to be lowered

• Multipurpose equipment- attachments etc

• Technical know how- operation and maintenance

• Future use of equipment- equipment used in one project should be used in another till its life

• Economical Aspects- cost effectiveness

• Reliability- Equipment must be reliable

• Operating Cost- fuel consumption and other running cost

• Past performance- historical data, reputation of manufacturer, warranty etc

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Finally• Anyone can buy a machine. But not

everyone can turn a profit with it. The

reason? You need more than a machine

for a successful business. Get answers to

questions like these:

– What type of material are you moving?

– What are the underfoot conditions?

– How much material has to be moved?

– What is the total job cycle distance?

– What are the job site time/production

requirements? 110

Questions

? ?

?

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THANK YOU ALL

Satya Narayan ShahB.Sc. in Mechanical Engineering (India)MS in Manufacturing Engineering & Management (UK)

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Contact: er.snshah@gmail.comsnshah@wlink.com.np

Ph. No: 9851004366