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CONSTRUCTION TECHNOLOGY & maintenance PowerPoint Presentation
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  2. WEEK 6 Construction Plants

  3. WEEK 6 CONSTRUCTION PLANTS • Principles and factors of plant selections • Types, functions and capabilities of moving machines

  4. LEARNING OUTCOME • At the end of week 3 lectures, student will be able to : • Describe the principles and factors of plant selections. (CO1; CO2; CO3) • Identify various types of construction equipments, i.e., moving, stationary, compaction and lifting machines. (CO1; CO2) • Identify the types, functions, capabilities and selections of moving machines. (CO2; CO3)

  5. CONSTRUCTION PLANT • THREE PINCIPLE CONSIDERATIONS:- • Technical efficiency • Ability • Requirement • Correct specification • timeframe • Commercial and financial ability • Cost • Availability • Supplier (location and numbers of supplier) • within the timeframe

  6. Factors Selecting Equipment • The function to be carried out • Standard or special types of equipment • Capacity of the equipment • Method of operation • Replacement of parts • Maintenance and repairs • Investment costs • Operating cost

  7. Types of Construction Equipments • Used to ground leveling and bulk earthmoving. Divided into two :- • Moving Machines- • Bulldozers, loaders, scrapers, graders and trenching machines • The excavated material is removed, transported and deposited • For removal of large of earth • Stationary machines • Face shovels, backhoes, draglines and grabs • The excavator loosens the soil and loads without changing position • Loss of mobility compared to scrapers and bucket loaders • More force may be applied

  8. Equipment of Earthwork Plant

  9. MOVING POSITION MACHINES • Bulldozers and angledozers • High powered tractors with caterpillar or crawler tracks • Fitted with a mould board or blade at the front for stripping top soil, clearing vegetation and oversite excavations up to depth of 400 mm • Work by pushing the material ahead of the machine • Also for opening up pilot roads, spreading and grading

  10. MOVING MACHINE -Bulldozers and angledozers • For back filling operations the angledozer with its mould board set at an angle (in plan) to the machine center line can be used • Assembled in two separate sections • base frame • Attached with dozer blade, drive sprockets (a projecting tooth on a wheel or cylinder that engages with the links of a chain or with perforations in film to make the chain or film move forward) and • rollers for the track and support for the upper body • Superstructure • Engine, transmission, hydraulics, cab and controls (mounted on the base frame)

  11. MOVING MACHINE - Crawler tracks • Advantages • Ability to deliver greater effort especially in operating on soft footing such as loose soil or muddy soil • Ability to travel over muddy surface • Ability to operate in rocky formations where rubber tires might be seriously damaged • Greater floatation because of the lower pressure under the tracks • Greater versatility on jobs

  12. MOVING MACHINE –WHEEL MOUNTED • Advantages:- • Higher travel speeds on the job or from one job to another • Elimination of hauling equipment to transport the bulldozer to a job • Greater output especially when considerable travelling is necessary • Less operator fatigue • Ability to travel on paved highways without damaging the surface

  13. MOVING MACHINE - Cable control • Advantages :- • Simplicity of installation and operation • Simplicity of repairing the controls • Reduction in the danger of damaging a machine , as the blade can be move up and ride over a rigid obstruction such as heavy boulder

  14. MOVING MACHINE -Hydraulic control • Advantages: - • Ability to produce a high down pressure on the blade in addition to its weight to force the blade into the ground • Ability to maintain a more precise setting of the position of the blade

  15. Blades used • Types of blades : - • Straight ‘S’ blade • Universal ‘U’ blade • Angle ‘A’ blade • Cushion ‘C’ blade • Rake

  16. ‘S’ Straight Blade Straight ‘S’ blade • Used for heavy work • Most versatile bulldozer • Equipped with a push plate effectively used for loading scraper • Most blade are curved, but the section perpendicular to the line of push is straight • The maximum of push should not exceed 100m as the machine is uneconomical for earth moving over a greater distance

  17. UNIVERSAL ‘U’ BLADE • The blade in cross-section has a much deeper curvature, almost a ‘u’ shape • Efficient for moving big loads over long distance as in land clearing, stockpile work and pushing up for loading • Shall combined with a tilt cylinder to improves its ability to ditch, pry out and level • Effecting to light flowing type of soil

  18. Angle ‘A’ blade • The blade in plan view is angled • Can also be positioned straight or angled 25 degrees to either side • Designed for side casting, backfilling and other similar tasks • Can reduce the amount of manoeuvring required to do this job

  19. Cushion ‘C’ blade • Used on a large tractors for on-the-go push loading • Rubber cushion allow the dozer to absorb the impact of contacting a scraper push block and effective travelling speed is up to 5 km/h • When not push loading, the dozer can be used for general dozing jobs

  20. Rib Rake • A blade consisting a heavy duty ribs which retained coarse rock, roots etc, but allow finer material to pass through • Used in digging and pushing stumps and rock and also in spreading of rock rip-rap

  21. FACTORS INFLUENCING SELECTION OF BLADES • Type of material to be moved • Particles size and the shape of materials to be moved • Rounded particles tend to roll and required a tractor of lesser power than for angular particles • Voids ratios of the soil in the bank or undisturbed condition • A soil with small voids will be well bonded and difficult to move until the material is loosened • Moisture content of the soil greatly affects the pushing forces required • Soils with high moisture content levels such as clay tend to be heavy and required large pushing effort • Size of machine and the traction capabilities

  22. MOVING MACHINE - SCRAPERS • The piece of plants consist of a power unit and a scraper bowl • used to excavate and transport soil where surface stripping, site levelling, light clearing, rough and fine grading, bank sloping, ditching/channel and cut and fill activities • Particularly for large volumes • Produce a very smooth and accurate formation level

  23. MOVING MACHINE - SCRAPERS • Three basic types:- • Crawler-drawn scraper • Two-axle scraper • Three-axle scraper

  24. CRAWLER-DRAWN SCRAPER • Has truck and gooseneck arrangement • Consist of four-wheeled scraper bowl towed behind a crawler power unit • Hauling speed - less than 8 km/h • Scraping speed – less than 3 km/h

  25. Wheel scraper • Is an integrated self-propelled unit • Two-axle • have two wheeled power unit has advantages over its four wheeled power unit or three axle due to its manoeuvrable • Offers less rolling resistance and has better traction since the engine is mounted closer to the driving wheels • Three-axle • Advantages of being able to use its top speed more frequently, generally easier to control and power unit can be used for other activities which is not possible with most two-axle

  26. Loading of scrapers • Scrapers are loaded by the following methods:- • Self loading in loose soils • Push loaded by crawler tractor • Elevating self loading • Push pull • Top loaded by hydraulic excavator or front end loader

  27. Scraper cutting blade Cutting Blade for Scraper • Standard Blade – used for fine grading and finishing and for general earthmoving operations where the soils are not too stiff or hard • Drop Centre Blade – Operates in broad range of soil and for stripping grass and root bound soils. The centre section is dropped so as to prevents the dam up of the materials inside the bowl when loading and unloading. • Double Drop Centre Blade – Used in heavy clay or where the material has a tendency to loosed in sheets. • Drop Centre Tooth Mounted Blade – operates efficiently on material which are hard or crusty.

  28. MOVING MACHINE - GRADERS • Similar to bulldozers – have an adjustable mould blade fitted either at the front of the machine or slung under the centre of the machine’s body • Use for finishing fine limits large areas of ground which has been scraped or bulldozed to the required formation level • Can only be used to grade the surface since their low motive power is insufficient to enable them to be used for oversite excavation work • Classified by number of driving wheels

  29. Mouldboard lifting Leaning wheel Drawbar Blade (Mouldboard) TYPES OF GRADERS - SIX WHEELED DRIVE GRADERS • Extremely good manoeuvrability and best for heavy work • Poor underfoot conditions

  30. Types of graders - Four wheeled drive graders • High traction for their weight • Require a wider working path and operators need to learn unusual operating techniques to make use of their superior potential

  31. Types of graders - Articulated graders • Able to pivot in the middle • Smaller turning radius- so can turn in much quicker time • Three modes of operations • Straight mode • Articulated mode - allows turning • Crab mode – rear driving wheels to remain firm ground while the machine cuts banks, side slopes or ditches

  32. Articulated grader position

  33. BLADES FOR GRADERS • Consists of a curved mould board ranging between 3 to 5 m long with replaceable ages on sides and bottom • Used for: • Levelling and trimming on the horizontal • Levelling and trimming to the slope and vertical face • Forming ditches • Backfilling along trenches

  34. MOVING MACHINE - TRACTOR SHOVELS/LOADERS • Sometimes called a loading shovel or front-end loader • Basically in the form of wheeled or crawler tracked tractor with a hydraulically controlled general purpose bucket mounted in front of the vehicle • Primary function to scope and loose material in the bucket, raise the loaded spoil and manoeuvre into a position to discharge its load into an attendant lorry or dumper • Can also transport, spread and compact fill material depending upon the mounted attachments • The tractor shovel is driven towards the spoil heap with its bucket lowered almost to ground level and uses its own momentum to force the bucket to bite into the spoil heap thus filling the scoop or bucket

  35. MOVING MACHINE - Buckets for loader • Design with long, flat floors to enables them to penetrate the most tightly packed stockpiles • Built for optimum payload and road retention • Faster cycle times lower operating costs • Flexibility to match with the job • Increased production and optimum performance • Two types:- • General purpose buckets • Penetration bucket

  36. MOVING MACHINE - Buckets for loader Buckets for loader

  37. General purpose buckets • Use in most application • Equipped with bolt-on teeth, bolt with reversible cutting edge or bolt on tooth and segments • Use spade-edge bucket for rock digging to improves ability

  38. Flat floor Flush mounted weld-on teeth Curved, sharp side bar Tooth Options Tip Options Penetration bucket • Use for material requiring moderate breakout and impact forces • E.g grading or stripping top soil • Cutting edge is equipped with weld-on, flush-mounted teeth adapters and integral corner teeth adopters

  39. Combination four-in one bucket • Is the most favourable • Can be set in the scrapper position, bulldozing position, spreading and levelling and back dragging

  40. Combination four-in one bucket • Consist of two major segments:- • The rear segments is a dozer blade with a straight cutting edge • The front segment is hydraulically operated calm with a straight cutting edge at the front, equipped with digging teeth Front segment Rear segment