Road and Bridge Construction Equipment

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(1)ROAD & BRIDGE CONSTRUCTION EQUIPMENT. Satya Narayan Shah B.Sc. In Mechanical Engineering (India) MS in Manufacturing Engineering & Management (UK). JANUARY ,2012. 1.

(2) Generally, we use the Equipment when a job requires 1.. SPEED. 2.. QUALITY. 3.. ECONOMY. 4.. EMERGENCY/DISASTER MANAGEMENT 2.

(3) 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 3.

(4) 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 Broom . 4.

(5) 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.

(6) 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.

(7) 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 7.

(8) 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 . 8.

(9) Dozers.

(10) DOZERS: Introduction • Earlier, the Dozers were developed on farm tractors by an American company (Holt Manufacturing Company) around in 1904 which is later became Caterpillar Inc. • These days, Dozer has become one of the most representative strong construction machinery. • Also commonly known as Bulldozer/ Tractor. • Dozer is a self-propelled unit that are designed to provide high tractive power for drawbar work. • High stability at work. 10.

(11) Dozer: Component arrangement Engine. This is the primover that provide power to run/ work the machine.. Power Train. This is transmit Engine power to final drive of the machine. Blade. This is working tools use to push earth cutting and leveling the ground. 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. Undercarriage. This is the feet of the machine that use to move / turn machine 11.

(12) Dozers: Main Parts / Systems • Upper Parts. (Track Dozer). – Engine – Transmission Power train – Cabin / Control Panel. • Undercarriage. ]. – Track Frame – Sprocket/ Idler – Track Chain – Track Roller – Carrier Roller. • Hull / Body Frame 12.

(13) 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) 13.

(14) APPLICATIONS OF DOZER Typical Applications are: – Dozing / Pushing materials – Sidehill Cut – Backfilling – Ripping – Land clearing – Ditching – Towing/Pushing other piece of construction equipment – Assisting scraper in loading 14.




(18) TYPES OF DOZERS 1. Crawler / Track Type. 2. Wheel Type. Track Dozer Wheel Dozer - Can work on variety of soil surface. - Good on firm soil and concrete surface. - Can work over almost all terrain. - Best for level and downhill work. - Can work on soft ground and mud-stick - Can not work on soft ground and mudsurfaces. stick surfaces. - Exert low ground pressure. - Exert high ground pressure. - Good for short working distance. - Good for long working distance. - Slow return speed. - Fast return speed. - Can push large blade load. - Can only push moderate blade load18.

(19) Crawler or Track Dozer • Have a continuous TRACK of linked shoes that moves in the horizontal plane across fixed rollers. • Track passes over the vertically mounted SPROKET at rear and IDLER WHEEL at front. • The SPROKET (mounted on final drive), pass on the power to the track chain that impart the forward or backward motion. • ROLLERS (Track and Carrier) support the Track chain. • The IDLER WHEEL is mounted on a recoil device (Mostly Recoil Spring) for adjusting track tension and absorbing 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. 19.

(20) Wheel Dozers • The front frame and rear frame is connected by the vertical central pivot. • Wheels are mounted on front and rear axles. • Power from final drive exert rimpull force that turns the wheels and moves machine in forward or reverse direction. • Traction force can be improved by proper tyre selection. Wider tyres provide greater contact area and increase flotation. • Larger sized tyre will reduce developed rimpull.. Have all powered Wheel Drive.. four. Breaking action on wheels as in Vehicle. Steering Articulation and Rear Equipment. achieved by between Front portion of the. 20.

(21) Dozer’s BLADE • BLADE is the main working tools (Implements) mounted on “C” frame in front of the machine perpendicular to direction of travel which PUSH (cut/ shear/ rolls) earth cutting in forward direction. • In the case of ANGLE DOZER blade is mounted on “C” frame at a set angle with direction of travel and push materials forward at one side.. BLADE. C-Frame. 21.

(22) BLADE Adjustments: Tilting TILTING: • 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. 22.

(23) BLADE Adjustments: Pitching PITCHING: • 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.. 23.

(24) BLADE Adjustments: Angling • Turning the blade so that it is not perpendicular to the direction of the dozer’s travel. • Angling causes the pushed material to roll of the TRAILING END of the blade called side casting.. 24.

(25) 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. 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.. 25.

(26) Hydraulic Excavators.

(27) Hydraulic Excavator Hydraulic Excavator is the most commonly used construction machine. it has bucket with specified volumetric capacity. Hydraulic power is the key utility to operate the hydraulic excavators. It can work at very high gradient and difficult terrain. With various front attachments, it can be used for diversified purposes. Most excavators are mounted on track base, but smaller model may be mounted on wheels base. 27.

(28) 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.

(29) Upper Structure: Cabin Interior 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. 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. Travel Levers Depending on moving direction of control Lever/ Pedals Machine can move straight or turn left or right.. Work equipment control Joystick. Machine monitoring units (Temp., Press. Gauges) Work equipment control Joystick Engine starting switch Fuel gauge. Travel Pedals Operator’s seat. n InteriorCabi. Lights / Other switches 29.

(30) Excavators: Swing mechanism The outer race fixed at upper structure turns with the “Pinion” that spins along with the inner race fixed at the lower structure.. SWING CIRCLE The part between the outer race and the inner race turns smoothly on the ball bearings.. Pinion. Outer race. Inner race This part enables an hydraulic excavator to turn around. Ball bearings Stick/Swing Controls (Left Joystick) move forward and backward to move stick out and in move left and right to control direction of swing 30.

(31) Lower Structure: Undercarriage Most 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 type excavator make use of supports/ Stabilizers during work.. WHEEL (TYRE). Can also be fitted with dozing blade . (Optional). CRAWLER / TRACK. Seen from the sides. Seen from the underneath. The part touching the ground surface 31.

(32) Hydraulic Excavators: How it Works ? Hydraulic Power is the key utility to operate all Hydraulic Excavators Arm Cylinder. Control Valves Hydraulic Pump. Boom Cylinder. Engine. Hydraulic Oil Tank Bucket Cylinder. Swing Motor Travel Motors. 32.

(33) Excavators : Types. • Based on mounting type; they are classified as: 1. Crawler or Track type 2. Wheel type. • Based on types of Bucket or digging motion of they are classified as: 1. Shovel type 2. Hoe type Both front SHOVEL type or HOE type Excavator can be mounted on either on a Crawler or a Wheel tractor base. 33.

(34) Hydraulic Excavator: Front Shovel Basic Features: • An upward motion unit is know as “front shovel” • Hydraulic front Shovel excavators are used mainly for hard digging above track level and for loading to hauling units. • A shovel develops breakout force by crowding material away from the machine. • The boom of a shovel swings upward to load; so the machine requires a material face above the ground level 34.

(35) Hydraulic Excavator: Hoe Basic Features: • A downward arc unit is classified as Hoe • Hydraulic Hoe excavators are used primarily to excavate below the ground level on which machine rest • It develops excavation breakout force by pulling the bucket towards the machine and curling the bucket inward. • The downward swing of a hoe dictates usage for excavating below the ground level at which machine rest. 35.

(36) 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 for almost all kind of applications. • A quick coupler enables to quick change with different type attachments and perform a variety of tasks in rapid succession 36.

(37) 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 of applications. • 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 and perform a variety of tasks in rapid succession. Some common attachments are: – – – –. Hydraulic breaker Clamshell Impact hammer Cutters. - Crane - Rock driller - Demolition jaw - Land clearing grapple 37.

(38) Typical Applications.

(39) Attachments. Various types of attachments. Building demolishing. Handling Scrap materials. 39.

(40) 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 40.

(41) LOADERS. 41.

(42) 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. 42.

(43) 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. 43.

(44) 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. 44.


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(50) 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 50.

(51) Dragline. 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 51 been constructed..

(52) 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.. 52.

(53) Dragline excavator. 53.

(54) 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.

(55) Dragline excavator with pile driver attachment.. 55.

(56) Bucket wheel excavator. 56.

(57) 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. 57.

(58) Scrapers. 58.

(59) 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 59 haul roads.



(62) Major Part of A Grader Transmission System. Tandem Drive. Hydraulic System. Operator’s Cabin. Moldboard. Circle Assembly. Draw Bar. Steering System. Blade. Main Frame. Attachments. 62. Prime Mover (Engine).

(63) ATTACHMENTS grader with attachments designed just for special application.  Increases the scope of works.  Best use of investment.  Reduce Idle time of equipment  Quality products. 63.  To add additional versatility to the motor.

(64) ATTACHMENTS 64.  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..

(65) ATTACHMENTS. 65.  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..

(66) ATTACHMENTS. 66.  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..

(67) ATTACHMENTS  Mid -mount Scarifier 67.  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..

(68) ATTACHMENTS  BLADE BOWL  Consists of two sideboards, a spreader bar, cutting 68. 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..

(69) ATTACHMENTS  Push block  The Push Block is mounted to the grader nose plate 69. 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..

(70) ATTACHMENTS 70.  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..

(71) ATTACHMENTS  SLOPER. (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.. 71.  Basically two kinds- for (a) shoulder works and.

(72) ATTACHMENTS  ELEVATING GRADER.  This attachment with a cutting disc, material 72. 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..

(73) ATTACHMENTS  GRADER SCRAPER. 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.. 73.  Consists of bowl, apron, and ejector, all.

(74) ATTACHMENTS  Rear mounted harrow  Series of Circular blades are banked. together and mounted .  Loosens, pulverizes and blends material.  Generally used in combination with Scarifier.. 74.  DISC HARROW.

(75) GRADER APPLICATIONS. 75. Graders may be used for: a) Cutting drains b) Bank battering c) Forming roads d) Levelling e) Mixing materials f) Scarifying g) Light ripping h) Windrowing i) Minor excavations j) Snow Plow k) Trench Cutter & Filler.

(76) Normal Blade Positions. 76.

(77) Covering Large Area. 77.

(78) Spreading Materials. 78.

(79) Blade Pitch. 79.

(80) Sloping High Bank. 80.

(81) Grading in Reverse. 81.

(82) Ditching or Ditch Cleaning. 82.

(83) Sloping During Ditch Cutting. 83.

(84) Backfill. 84.

(85) 1800.

(86) PURPOSE OF COMPACTION  To develop the potential strength of a 86. 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..

(87) The amount of compaction is influenced by the following factors.  The moisture content of the soil. 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.  The nature of the soil (Grain size distribution and.

(88) 88. 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).

(89) Types of Compaction Equipment Compactors can be grouped in the following types: -.  Towed tamping  Vibratory tamping.  Vibrating Rollers  Multi Tyred Pneumatic Rollers  Plate Compactors  Vibrating Compactors. 89.  Smooth Steel Drum Rollers  Sheep Foot Rollers  Grid or Mesh Rollers  Tamping Rollers.


(91) Smooth Steel Drum 91.  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..

(92) Smooth Steel Drum  Front wheel is on dead axle used for steering.  Rear wheels are powered.  Power is transferred from engine through. 92. 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..


(94) 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       . 94. . 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. ..


(96) 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.. 96.


(98) GRID OR MESH ROLLERS 98. The 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..

(99) Vibratory Rollers. 99.

(100) Vibratory Rollers  Eccentric Shaft creates Vibration due to centrifugal force.  Vibration has two measurements– amplitude, which is the.    . 100. . 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..

(101) Vibratory Rollers Dynamic force created by a vibrator’s mechanism can be calculated from the following calculation;. F=0.00034WRN2 101. Where, F = Dynamic force in pounds W = Weight of eccentric mass in pounds R = Radius from center of eccentric mass to center of rotation in feet N = 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..

(102) Vibratory Rollers. (cont……).  These rollers are gaining popularity due to versatile 102. 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.

(103) Small Walk Behind Rollers  Width in the range 24 to 38 inches. 103.  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..

(104) Multi tyred Pneumatic Rollers. 104.

(105) Multi tyred Pneumatic Rollers  Available upto 200 ton gross weight.  Surface rollers using Principle of kneading Action to effect .  .      . 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. 105. . 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.

(106) Plate Compactors/Rammers. 106.

(107) Plate Compactors/Rammers 107.  Lift 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..

(108) Vibrating Compactors. 108.

(109) 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 109.

(110) 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.

(111) Questions ?. ?. ? 111.

(112) THANK YOU ALL. Satya Narayan Shah B.Sc. in Mechanical Engineering (India) MS in Manufacturing Engineering & Management (UK). Contact: Ph. No: 9851004366 112.





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