Group Members :

Dafer Sief 00

Mohamed Amman 00

Boey Ying Yan 00

BDH 202

Building Construction 3

Tower Crane

Introduction• Tower cranes 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.

Function • The construction 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.

• Mast:the main 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.

• 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.

• Hook:

the hook (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

MATERIAL & FUNCTION

LUFFING JIB TOWER CRANE SELF ERECTING TOWER CRANE

TYPES OF TOWER CRANE

• The most important 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

DESCRIPTION OF LUFFING JIB TOWER CRANE

Base installation of LUFFING JIB TOWER CRANE

SELF ERECTING TOWER

CRANE

Tower Cranes Regulations

A tower crane should 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.

A tower crane should 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.

Where the driver is 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.

Any method of lifting other than the recommended vertical lifting of loads should be actively discouraged, as damage may be caused to the crane..

The tower crane driver 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.

The tower crane will have a maximum service wind speed, usually about 72 kph (45mph)and would haveto 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.

The tower crane must 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.

When the selection of 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.

When two or more 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.

Smaller tower cranes with 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.

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.

On some projects it 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.

Points to consider for 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)

HAND SIGN