Construction Equipment Lecture 5A PDF

WOLKITE UNIVERSITY COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF CONSTRUCTION TECHNOLOGY AND MANAGEMENT (For Hydraulic and Water Resources Engineering Students) CHAPTER FIVE Construction Equipment  CONTENTS  Int...

WOLKITE UNIVERSITY COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF CONSTRUCTION TECHNOLOGY AND MANAGEMENT (For Hydraulic and Water Resources Engineering Students) CHAPTER FIVE Construction Equipment  CONTENTS  Introduction  Classification of Equipment  Earth Work Equipment  Crane Shovel Family  Face Shovel, Drag Line, Clam shells, Hoes  Heavy Earth moving Equipment  Excavators, Loaders, Dozers, Scrapers  Grading Equipment  Graders  Compaction Equipment  Hauling Equipment The backhoe is the main tool of the backhoe loader. It’s used to dig up hard, compact material, usually earth, or to lift heavy loads, 2 such as a sewer box CONSTRUCTION EQUIPMENT 1. Introduction Classification of Construction Equipment  Generally equipment types can be classified into Productive and Support equipments. equipments I. Productive equipment are those units that alone or in combination lead to an end product which can be recognized as a unit for payment;  Include pavers, haulers, loaders, rollers etc. II. Support equipment are those equipments which are required for operations related to the placement of construction such as movement of personnel and materials, and activities that influence the placement of environment.  Include represented hoists, lighting sets, vibrators, scaffolds as typical support equipments 3 CONSTRUCTION EQUIPMENT  For the purpose of this course two major classifications of equipments largely based on the type of works involved are covered. I. Construction Equipment  Earth works equipment: Bulldozers, Shovels, Clamshells and Draglines, Loaders, Graders, Scrappers, Rollers, Drills, Grouting pumps, Pile driving and Hammers.  Hauling and Hoisting equipment - Tractors, Normal and Dump trucks, Scrapers, Hoists, Conveyors and Cranes.  equipment Compactors Compaction and stabilization equipment-  Foundation Equipment - Pile Driving Equipments  Pumping Equipment - Pumps, Hoses, Pipes, and Compressors.  Concreting equipment - Mixers, Vibrators  Tunnelling equipment - TBM  Drilling and blasting equipment 4 CONSTRUCTION EQUIPMENT II. Construction Plants  Aggregate production plants,  Crushers, Screens, Conveyors, and Feeders.  Asphalt mixing plant and  Aggregate Batchers, Bitumen Emulsifier, and Mixers.  Concrete Batching Plants and  Feeders, Mixers and Silos. 5 CONSTRUCTION EQUIPMENT I.1. Earth Work Equipment  Earth work includes:  Site preparation, excavation, loading, hauling  Embankment construction,  Backfilling, dredging,  Preparing base course,  Sub-base and sub-grade,  Compaction, road surfacing  All the above works involve the use of a large number of highly efficient and versatile equipment. 6 CONSTRUCTION EQUIPMENT Earth Work Equipment  Earth work equipments are broadly classified into earth moving, compaction, grading and hauling equipment. equipment Earth Work  Definition Earth work is a process of moving soil or rock from one Definition:- location to the other and processing it, so that it meets construction requirements of location, elevation, density, moisture content, etc.  The proper selection of these equipment and the length of time they will have to be used are an essential part of the estimator’s work. 7 CONSTRUCTION EQUIPMENT Earth Work Equipment  Excavators A  Loaders B  Shovels  Clamshells  Draglines  Scrapers E  Dumpers C  Dozers  Graders  Rollers D F H G I J CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family A. Face Shovel  Face shovel is an equipment used mainly in quarries, pits and on construction sites to excavate and load blasted rock.  These equipments are more effective for excavations above the wheel or grade level.  The basic parts of a power shovel include the mounting, cab, boom, dipper stick, dipper (bucket), and hoist line.  Optimum depth of cut:cut is that depth which produces the greatest output and at which the dipper comes up with full load without undue crowding.  The depth varies with the class of soil and the size of the dipper.  It may cost about 10 Million ETB 9 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family A. Face Shovel  The output of a shovel is affected by numerous factors, including the following:  Class of material,  depth of cut,  angle of swing,  job conditions,  management conditions,  size of hauling units,  skill of operator and  physical condition of the shovel. Wheel Grade Level 10 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family B. Drag Line  Draglines are used to excavate earth and load it into hauling units, such as trucks or tractors-pulled wagons, or deposit it into levees, dams and spoil banks near the pits from which it was excavated.  These equipment are more efficient for excavation below the grade level and have the longest reach of all shovel equipment.  A dragline can be used for dragging out sediments and is efficient for under water construction.  These equipment are weak while excavating hard materials and have a lesser productivity than a face shovels. 11 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family B. Drag Line  Lines Drag lines may be divided into three types: Types of Drag Lines:  Crawler-mounted  Wheel-mounted, self-propelled  Truck-mounted  Crawler-mounted draglines can operate over soft ground conditions that would not support wheel or truck - mounted equipment.  The travel speed of a crawler machine is very slow, frequently less than 1 mph,  It is necessary to use auxiliary, hauling equipment to transport the unit from one job to another.  Wheel and track-mounted units may have travel speeds in excess 12 of 30 mph. CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family B. Drag Line Output of drug lines  The output of drag lines will vary with the following factors  Class of material  Depth of cut  Angle of swing  Size and type of bucket  Length of boom  Method of disposal, casting, or loading  Size of the hauling units, when used  Skill of the operator  Physical condition of the machine 13  Job conditions CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family C. Clamshells  Clamshells are used primarily for handling loose materials such as sand, gravel, crushed stone, coal, etc. and for removing materials from inside cofferdams, pier foundations, sewer manholes, sheet-lined trenches, etc.  They are specially suited to vertically lifting materials from one location to another, as in charging hoppers and overhead bins.  The limits of vertical movements may be relatively large when they are used with long crane booms.  Clamshell buckets are available in various sizes, and in heavy-duty types for digging, medium-weight types for general-purpose work and lightweight types for rehandling light materials.  14 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family C. Clamshells  Manufacturers supply buckets either with removable teeth or without teeth. teeth  Teeth are used in digging the harder types of materials but are not required when a bucket is used for re-handling purposes. 15 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family C. Clamshells  The capacity of a clamshell bucket is usually given in cubic meter.  The variable factors affecting operations include:  The difficulty of loading the bucket,  The size load obtainable,  The height of lift,  The angle of swing,  The method of disposing of the load, and  The experience of the operator. 16 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family D. Hoes  Hoes are used primarily to excavate below the natural surface of the ground on which the machine rests.  hoe is sometimes referred to by other names, such as backhoe or back shovel. shovel  They are adapted to excavating trenches, pits for basements, and general grading work, which requires precise control of depths.  Because of their rigidity they are superior to draglines in operating on close- range work and dumping into trucks.  Because of the direct pull on the bucket, backhoes may exert greater tooth pressures than face shovels.  In storm drain and utility work the hoe can perform the trench excavation and handle the pipe, eliminating a second machine. 17 CONSTRUCTION EQUIPMENT Hoe Buckets  There are special buckets for everything from light sand to hard rock digging. Hydraulic Hoes  Bucket penetration (break out force) is developed by the hydraulic cylinders of the boom, boom stick and bucket. bucket Teeth option Bucket option Stick Bucket Boom 18 CONSTRUCTION EQUIPMENT D. Hoes Hydraulic Hoe Types  The hoe can be track or wheel mounted 19 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.1 Crane Shovel Family Comparison between the shovel family 20 CONSTRUCTION EQUIPMENT 2. Earth Work Equipment 2.2 Heavy Earth moving Equipment A. Excavators  Replaced the cable operated crane shove family  Excavators are basically digging machines, having the following three main components  An undercarriage to give mobility. This may be crawler track mounted or wheel mounted.  A superstructure with operator’s cabin mounted on either a slew ring to traverse through 360° or on a rigid frame.  Hydraulically articulated boom and dipper arms with bucket. bucket  Excavators are designed to excavate below the ground surface on which the machine rests.  Good mobility and versatility and excellent for general-purpose work, such as excavating trenches and pits. 21 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators Basic Parts of Excavator 22 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators  Functions of excavators:  Excavating – Earthworks  Loading Excavated Material  Scarification  Making of Drains  Advantages of hydraulic excavators include:  Faster cycle time,  Higher bucket penetrating force,  More precise digging, and easier operator control.  Many attachments can be made to increase the versatility of the equipments. 23 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators Types of excavators  Excavators are of the following types based on the type of carriers on which they are mounted: I. Crawler mounted excavator II. Truck mounted excavator III. Self propelled excavator IV. Excavators mounted on barge or rail I. Crawler mounted excavator:  These excavators are mounted on the crawler system and are very suitable for carrying out large works in rough terrain.24 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators Types of excavators I. Crawler mounted excavators:  Crawler excavators have the following main characteristics;  Can be used for work on soft or wet grounds  Can be used on sharp rocks or other adverse conditions  These can climb steep grades (even up to 40 percent)  Requires very less turning space  Have very less speed for travelling  Can be shifted from one site to another only on trailors 25 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators Types of excavators II. Truck mounted excavators:  These excavators are mounted on truck chassis and has the following main characteristics:  High road speed and mobility is the main advantage.  Lower stability over sides and hence require counter-weight or outriggers.  Require more operating space.  Tyres or outriggers give high ground pressure and hence it requires firm and smooth operating locations.  Have two engines and two cabs, separately for truck chassis and excavator. 26 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment A. Excavators Types of excavators III. Self propelled excavators:  These excavators are self propelled and has rubber tyres. The main characteristics are:  Medium travel speed generally between 10-30 Km per hour.  Has one engine and one cab for control by one operator. IV. Excavators on barge or rail:  These excavators are mounted on barge or rail to carry out work of excavation in water or near railway line respectively. 27 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders  A bucket is attached to the arms and capable of being raised, lowered, and dumped through mechanical or hydraulic controls.  The loaders having bucket in the front, known as “front end loaders” loaders are very common.  The loaders are versatile, self propelled equipment mounted either on crawler or wheel-type running gear.  These are equipments used primarily:  To load excavated materials to a hauling unit,  Excavate soft to medium materials,  Loading hoppers,  Stockpiling materials,  Backfilling ditches, and  Moving concrete and other construction materials. 28 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders Basic Parts of a loader 29 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders Types of Loaders  Loaders are of the following two types:  Crawler loaders  Wheel Loaders 30 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders Types of Loaders I. Crawler loaders  Crawler track types are generally preferred for digging and loading jobs where ground conditions are poor and low pressure characteristics are required.  They are preferable for applications involving rock and sharp stony ground as there is no possibility of tyre damage.  These are best employed for short moves between loading and dumping points.  They should be transported from one site to another after loading on the trailors. 31 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders Types of Loaders II. Wheel loaders  As a result of the development of more capable power trains (axel and tires), there was a steady trend towards wheel loaders at the expense of crawlers.  Wheel loaders are generally four wheel drive. drive However, for handling light jobs on good ground conditions two-wheel drive varients are also used.  Four wheel drive loaders are generally used for construction jobs, jobs whereas, two wheel drive loaders are used for bulk handling of coal, cement, fertilizer etc. 32 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders II. Wheel loaders  Some models of wheel loaders are designed as a combination of a backhoe and loader and often called backhoe loader. loader 33 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment B. Loaders Backhoe loader features  Very common piece of equipment  Many subcontractors own/lease  Very versatile  Easily transported  “Low” maintenance costs  Operator “friendly”  Easily rented 34 CONSTRUCTION EQUIPMENT B. Loaders Operations: Loaders are used to carry out the following main operations; A. Loading  Loading operation is the main operation performed by the loaders.  Loading consists of scooping, lifting, turning and dumping materials such as sand, gravel, and crushed materials from stockpiles, bank or construction site into the hauling units. B. Hauling  Wheel loaders are excellent for moving loose materials over short distances to dump into hauling units, hoppers, conveyors, bins, or any other place of work in the construction site. C. Excavating  Crawler loaders and heavy duty wheel loaders are excellent for many excavation jobs.  These loaders can excavate as well as lift the excavated material and dump it into trucks or on the stockpiles D. Clearing  Loaders can scoop up and load the debris of demolished buildings into hauling units.  Loaders are the first equipment to prepare the site for building 35 and construction operations; and also the last equipment in order to backfill, spread, level and top with selected good soil.  CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers  Dozers are machines designed primarily for cutting and pushing the material over relatively short distance.  They consist of a tractor equipped with a front–mounted earthmoving blade controlled by hydraulic cylinders to vary the depth of cut.  A dozer moves earth by lowering the blade and cutting until a full blade load of materials is obtained. It then pushes the material across the ground surface to the required location.  Rear mounted hydraulic scarifiers and rippers can be fitted to loosen hard material 36 prior to dozing. CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers Application of Dozers  The following are the main dozer application  Clearing land of timber and stumps,  Opening up pilot roads through mountains and rocky terrain,  Moving earth for the haul distances up to approximately 100m,  Helping load tractor-pulled scrapers,  Spreading earth fills,  Backfilling trenches,  Side hill cuts  Clearing construction sites of derbies, and  Maintaining haul roads. 37 CONSTRUCTION EQUIPMENT Application of Dozers Moving earth Helping scrappers 38 CONSTRUCTION EQUIPMENT Dozer Blades  The dozer blades are available in sizes from 2m to 7.5m wide and 0.8m to 1.5m height. height  Dozer blades are of the following types: A. U-Blade Used for moving big loads over longer distances; U-Blade: distances curved shape and side and top extensions reduce the spillage of loose material; best suited for lighter materials. materials B. Blade Used primarily for shallow surface removal, Straight Blade: removal land clearing; designed to push dirt for short distances, versatile, lightweight and maneuverable, handles a wide range of materials. C. Blade It is designed to move material towards the sides of a cut, Angle Blade: backfilling or cutting ditches, and sustainably reduces the amount of maneuvering. D. Blade) Used primarily with scrapers for ‘‘on the go’’ push C (cushion Blade): loading; can be used for lighter excavation and other general tasks. E. Blade These blades are specially designed to handie refuse and/or Land fill Blade: fill material. 39  CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers Dozer Blades Carry Dozer “CD” Straight “S” Blade SU-Blade U-Blade Blade V-Tree cutter Power Angle & Variable Radius Rakes -Blade K/G -Blade Tilt Blade “VR” Blade 40 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers Crawler Vs Tyre Tractors A. Crawler Mounted tractors B. Wheel Mounted tractors 41 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers Crawler Vs Tyre Tractors  Each type of tractor has certain advantages in certain conditions.  Advantages of crawler mounted tractors: 1) More tractive effort, hence can also operate on loose or muddy soil. 2) In absence of tyres, can easily operate in rocky conditions. 3) Where maintenance of haul roads is difficult, it can easily travel, especially in rough terrain. 4) Crawler tractors are more compact and powerful and hence can handle difficult jobs as well. 5) Greater floatation because of the lower pressure under the trucks. 42 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment C. Dozers Crawler Vs Tyre Tractors  Advantages of wheel mounted tractors: tractors 1) Can travel at higher speeds during operations and also from one job to the other. 2) Ease in operation. Operator feels less fatigue. 3) Can travel on paved roads without damaging them. 4) Can travel long distances at its own power, whereas crawler mounted needs trailors. 5) When work is spread over long area, these are found to be producing more output. 6) Operation, maintenance and repair costs are less in wheeled tractor as compared to crawler tractors. 43 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers  Scrapers are capable of excavating, hauling and dumping material excavating hauling, over medium- to long-haul distances.  The scrapers are designed to dig, dig load, haul dump and spread and load haul, sometimes called as carry all. all Types of scrapers  The scrappers are of three types: I. Towed scrapers:  They are provided with either cable or hydraulic control.  They are becoming obsolete.  When coupled to a suitably powered crawler tractor, they can operate in extremely adverse conditions. 44  Travel at slower speed and can be used for short hauls only. CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers Types of scrapers II. Self propelled or motorized or conventional scrapers:  Generally manufactured in ranges from 10-20 cubic meters.  Needs push loading by a crawler mounted or wheeled tractor.  Have more hauling speed and hence are suitable for long distance hauling. III. Self loading or elevating scrapers:  The problem of loading by a pusher is overcome by these type of scrappers.  These are twin engine scrappers and can work completely independently of all other plants.  Pay loads are restricted because of the additional weight of the loading elevator and its drive system. 45  CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers  Types of scrapers :Another classification method of scrapers Conventional (Push loaded) Become uneconomical when Haul grades > 5% Return grades > 12% Tandem powered Twin Engine Good for jobs having adverse grade Owning operating costs are about 25% higher 46  CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers  Types of scrapers Push pull scrapers  Can work as a team or operate individually with a pusher.  Tire wear will increase in rock or abrasive materials. Elevating scrapers  Good for short hauls and in favourable materials.  Can work alone in the cut.  Cost more initially and to operate. 47 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers Types of scrapers Auger Scrapers  Can self load in difficult condition, laminated rock or granular material.  The augers add weight to the scraper during travel and it is more costly to own and operate than the conventional. 48 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers Operation  Operation of a scraper is described here under for an earth work: i. Loading or digging  The operator moves to the cut with the ejector at the rear and the apron raised approximately to 40 cm.  The bowl is then lowered to the desired depth of cut, increase engine speed, move forward in first gear keeping optimum depth of cut.  When the bowl is full, the apron is closed and the bowl is then raised. ii. Transporting  The bowl is transported in high gear in raised position to provide sufficient clearance.  During transporting, apron should be fully closed 49to prevent loss of material CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers Operation  Operation of a scraper is described here under for an earth work: iii. Unloading  The bowl should be positioned to spread the material to the desired depth during this operation.  A partial opening of the apron during the initial unloading will help in even spreading.  For wet and sticky material, the apron should be raised and lowered repeatedly until the material behind it is loosened and drops out of the bowl.  Then the ejector is moved forward to push the remaining material out of the bowl at a uniform rate.  When the dump is complete, the tail gate is fully retracted, the apron dropped and the ‘bowl’ raised to transporting position. 50 CONSTRUCTION EQUIPMENT 2.2 Heavy Earth moving Equipment D. Scrapers Operation  Following are some of the suggestions for increasing scraper production: production  Construct and maintain smooth haul roads for faster travel.  Depth of cut should be according to the type of soil being cut.  Use ripper teeth in hard or abrasive materials for easy handling.  Where possible, loading be done in down grade  To increase the stability of the scraper during travel, carry the bowl as close to the ground as possible.  If necessary pre-wetting of the soil is done so that the soil is reasonably moist, as most soils load easily when they are moist.  Whenever possible, plan the work to eliminate all avoidable 51 turns. CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders  Grading is the process of bringing earth work to the desired shape and elevation (grade).  Motor graders are used for leveling and smoothening the earthwork, spreading and leveling the base course in the construction of roads and air fields.  Motor graders can be used for the following types of works:  Gravel road repairing  Road shoulder reshaping, bank cutting and reshaping  Ditch filling or digging  Levelled or slopped ground finishing  Base course spreading and levelling  Material mixing, hard surface cutting, snow clearance,  Land clearance, frozen top soil and asphalt breaking 52 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Comparison with dozers  A grader is restricted to making shallow cuts in medium-hard materials.  They should not be used for heavy excavations.  A grader can move small amounts of material but cannot perform dozer-type work because of the structural strength and location of its moldboard.  Graders can work on slopes as steep as 3:1.  Grader are capable of progressively cutting ditches to a depth of 3 ft. 53 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Basic parts of grader  The components the grader that actually do the finishing are:  Blade (Moldboard)  Scarifier  Rippers Scarifier log Rear Ripper Moldboard/ Circle Blade 54 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Blade  The blade (Mould Board) is the main tool of the grader.  It is carried by a rotating circle and is easily maneuverable to a wide range of cutting positions with the help of hydraulic controls.  The blade and the circle are mounted on a frame and is supported at the front of the machine by a ball joint.  The blade can be adjusted to any position with help of levers as indicated below: shift the blade has Blade Sideshift Ram  Side shift: blade The blade can be lifted or  Lifting the blade: lowered by levers operating the two rams. circle A hydraulic motor is  Rotating the circle: provided to rotate the circle and blade. Blade can be rotated either in clockwise or counter clockwise direction. 55 Adjusting blade cutting angle CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Scarifier  Scarifier is a special tool attached with the motor grader for loosening the hard soil and has a set teeth mounted on adjustable shanks.  This attachment digs up hard ground like asphalt, old pavement, frozen surface and hard soil with vegetation and brushes which can not be removed by the blade.  The teeth are replaceable, and the number of teeth can be varied to suit the ground hardness.  High strength alloy steel tips can be mounted on the teeth to prevent teeth wear and extend their service for economical performance. 56 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Scarifier 57 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Ripper  The ripper is used to break up materials too hard to cut with moldboard blade.  The depth of cut is controlled by hydraulically operated ripper control lever.  Type of material to be ripped will determine position of the ripper shank. 58 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Various Operations A. Grading:  Grading in road construction means flattening and smoothening the road surface and others by the scrapping action of the blade, includes working operation like, surface skimming, skimming light duty bulldozing, bulldozing leveling spreading and crowning. leveling, crowning  A cutting depth of 2 to 3cm is considered to be the best for optimum efficiency. Under no circumstances it should be greater than 5cm. B.Spreading:  Gravel together with binding material is spread by the motor grader.  For spreading the cutting angle is set at 60° nearly.  Cutting edge of the blade is set above the ground at a distance equal to the depth to which the material is to be spread. 59 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Various Operations C. Finishing and Leveling:  In final finishing and leveling, surface have to be finished to fine limits.  In such cases make the finishing pass with the blade only slightly angled and set to skim the surface. D. Ditch Digging:  The front end of the blade is tilted down and the rear end is tilted up above the road surface. The front end cuts into the ground.  This is used to dig drainage ditches and road side ditches. E. Cutting:  For the purpose of cutting in soft dirt, set the blade to an angle b/n 40-55 degree, while in hard dirt an angle of 30-45 degree is proper. 60 CONSTRUCTION EQUIPMENT 2.3 Grading Equipment Graders Various Operations Laser Blade controls Ditch Cutting 61 CONSTRUCTION EQUIPMENT 2.4 Earth work Equipment Summary 62 CONSTRUCTION EQUIPMENT 2.4 Earth work Equipment Summary  Choice of Excavation Equipment for Building Site Excavation depends on:  Size of the job: - Bucket Size and Number of Excavators  Activity time constraints: - Number of equipment  Availability of equipment:  Cost of transportation of equipment:  Type of excavation:  Soil characteristics:  Geometric characteristics of elements of the soil to be excavated:  Space constraints:  Characteristics of haul units:  Location of dumping areas: 63  Weather and temperature: CONSTRUCTION EQUIPMENT 2.4 Earth work Equipment Summary 64 CONSTRUCTION EQUIPMENT 2.4 Earth work Equipment Summary 65 THANK YOU! 66