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Tower crane
- 1. BDH 202 BuildingConstruction 3 Tower Crane Group Members : Dafer Sief 00 Mohamed Amman 00 Boey Ying Yan 00
- 2. Introduction • Towercranes are a common fixture at any major construction site. • A crane with a fixed vertical mast that is topped by a rotating boom and equipped with a winch for hoisting and lowering loads. The winch canbe moved along the boom so that any location within the diameter of the boom can be reached. • Its often rise hundreds of feet into the air, and can reach out just as far.
- 3. Function • Theconstruction crew uses the tower crane to lift the building materials : • steel, concrete, large tools like acetylene torches and generators, and a wide variety of other building materials.
- 6. • Mast: themain supporting tower of the crane. It is made of steel trussed sections that are connected together during installation. • Slewing Unit: the slewing unit sits at the top of the mast. This is the engine that enables the crane to rotate.
- 7. • Operating Cabin: the operating cabin sits just above the slewing unit. It contains the operating controls. • Jib: the jib, or operating arm, extends horizontally from the crane. "luffing" jib is able to move up and down; a fixed jib has a rolling trolley that runs along the underside to move goods horizontally.
- 8. • Hook: thehook (or hooks) is used to connect the material to the crane. It hangs at the end of thick steel cables that run along the jib to the motor. • Weights: Large concrete counterweights are mounted toward the rear of the mast, to compensate for the weight of the goods lifted
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- 10. TYPES OF TOWERCRANE LUFFING JIB TOWER CRANE SELF ERECTING TOWER CRANE
- 11. • The mostimportant substance used to manufacture cranes is steel. Steel is an alloy of iron and a small amount of carbon. For structures that do not require very high strength, a common form of steel known as carbon steel is used. By definition, carbon steel contains less than 2% of elements other than iron and carbon. Carbon steel exists in a wide variety of forms. The most important factor in determining the properties of carbon steel is the amount of carbon present, which ranges from less than 0.015% to more than 0.5% REFERANCE : Read more: http://www.madehow.com/Volume-5/Crane.html#ixzz3K36K3WKe
- 13. DESCRIPTION OF LUFFINGJIB TOWER CRANE
- 14. Base installation ofLUFFING JIB TOWER CRANE
- 15. SELF ERECTING TOWER CRANE
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- 18. A tower craneshould only be erected or dismantled and tested by competent persons, i.e. an engineer and erection crew trained in the erection and dismantling of that type of tower crane.
- 19. A tower craneshould only be operated by a trained and competent operator who is physically fit, including eyesight and hearing, conversant with the type of crane, and able to cope with the conditions existing on site.
- 20. Where the driveris required to move loads under the control of another person, a suitable slinger/signaller should be provided who is conversant with the lifting capabilities of the tower crane and able to communicate clearly with the driver via hand or radio signals.
- 21. Any method oflifting other than the recommended vertical lifting of loads should be actively discouraged, as damage may be caused to the crane..
- 22. The tower cranedriver must be capable of carrying out a weekly inspection of his crane and should be given sufficient time in which to do this. A report of such an inspection must be made in an appropriate document.
- 23. The tower cranewill have a maximum service wind speed, usually about 72 kph (45mph)and would have to be substantially reduced according to the area and weight of the load being handled by the crane. The crane operator must be given sufficient authority to decide when the crane should be put out of service，because of high winds and his inability to control the load.
- 24. The tower cranemust always be in a position to rotate (slew freely) when it is placed into the out of service? condition. The slew brake should not be left on under normal conditions.
- 25. When the selectionof a tower crane is being made against particular environmental considerations, the following are an example of what might have to be taken into account. 1. Overall area to be covered; 2. The height of the building; 3. The required speed of the lift; 4. Weight of critical loads; 5. The type of base or mounting; 6. Existing ground conditions; 7. All proximity hazards; 8. Types of jib; 9. Erection; 10. Dismantling.
- 26. When two ormore tower cranes are employed on a site, each should be erected to a different working height to prevent the possibility of collision between the jibs. Although the jibs may over slew? the load may still contact the lower crane. Rail track should be placed strategically to prevent the jib of one crane hitting the tower of another.
- 27. Smaller tower craneswith lighter lifting capacity are usually more suitable on projects where traditional methods of building in brick, concrete etc. are employed. In these situations the lorry or crawler mounted tower crane may be the right one for the job.
- 28. The bigger cranes,with their greater lifting capacities, are more suitable for projects where constant off-loading and placing of heavy prefabricated units occur. Here, speed may have to be sacrificed in the interests of precision lowering and placing.
- 29. On some projectsit may be more economical to use a rail-mounted crane. On others a static or climbing crane may be the answer. On some sites, the proximity of high obstructions will prevent the use of an horizon-jib tower crane, and a luffing (erricking) jib tower crane will have to be employed. The luffing-jibbed tower cranes have all three base variations; free-travelling, static and climbing.
- 30. Points to considerfor operating a tower crane safely - Have all of the specific hazards associated with the work in progress been analyzed? - Has specific training with respect to the hazards of operating a tower crane been provided (authorized crane operator, fall protection, material handling, rigging, signalling) - Are rescue procedures in place? - Has the tower crane been properly maintained (maintenance record, log books)? - Has the tower crane been properly inspected before erection (non-destructive testing report, components identified and tracked to ensure all structural components inspected)? - Has the tower crane been properly inspected after erection (engineering reports for the foundation, shoring and bracing, structural integrity of the building, drawings and reports to be approved and signed by a professional engineer)
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