AOR adds new Leibherr Crane to line up

by jonhunt on August 20, 2013

All-terrain mobile crane
LTM 1055-3.2

The three-axle mobile crane LTM 1055-3.2 is the most powerful crane in its class. The 55 tonner is setting standards with its extensive technical range. Fully-automated levelling of the outriggers and ballasting with advanced keyhole technology increases the quick readiness for operation of the crane.

How are Tower Cranes Built?

by jonhunt on August 1, 2013


A Tower Crane Mast Section is set into a foundation with steel pedestals. The Mast Section is is plumbed to a degree of 1:500 (ie It must not deviate more than 1 inch from plumb for every 500 inches vertical) . Concrete is poured and then the crane is ready to be erected after the curing of the concrete.

 

 
A 40’ Tower crane base is being set. 16 bolts are installed. The bolts have nuts that are 2 5/16” and are torqued with a hydraulic wrench to as much as 4300 ft lbs. By comparison, the lug nuts on most cars torque to 115 ft lbs.
The process continues as mast sections are added until the needed height is achieved. The turntable (operator cabin included) is added in the same manner and is often the heaviest piece of the crane. In some applications this section is split to reduce weight on the mobile crane. This may add two hours to the crane erection process, so it is avoided when possible.

After the Turntable is installed the Tower Top is added and four large pins are added as the connecting members.

 
While the bolts on the Mast Section bolts are tightened, the jibs for the crane are assembled.

The Counter Jib is erected as one piece. It is connected by large gates or pins at the turntable. After this connection is made it is elevated by the mobile crane to around 15 degrees above horizontal. The pendants are connected by pins with cotter pins. Then the Counter Jib is lowered to horizontal. Sometimes the Machine Package with Electrical Panel and Hoist is with the Counter Jib and other times it’s installed separately. After this, any needed Erection Ballast is installed in the Counter Jib.

 
The Working Jib of the crane is installed at the turntable and elevated with the Mobile Crane. After it is elevated the Tower Crane hoist is connected to the pendant attached to the jib and pulled up to the Tower Top and connected with a pin. Then the Jib is lowered back to horizontal. The trolley is now installed if it wasn’t on the ground.

The installation of the Outer Section of the Jib is installed with the installation of three pins. Finally the Ballast (up to 60,000 lbs) is installed on the Counter Jib and the structural erection of the tower crane is complete. In most cases this end of the first day. {read the full article}

Different Types of Cranes

May 5, 2013

Cranes are machines that use levers and/or pulleys to lift significant weights. A crane one passes on the road may look like a fairly modern invention, but these machines have actually been used for at least the past 2000 years, if not longer. The Romans used cranes to build huge monuments. Medieval churches were constructed […]

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Tower Cranes Warrant a Closer Look

April 5, 2013

According to statistics, about 125,000 tower cranes are operating worldwide and, on average, are erected in 2 days on various jobsites to build skyscrapers. There are two types of cranes, tower and mobile, which can be purchased or rented depending on the company’s scope of work. Mobile cranes are limited because they must be moved […]

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Rigging Safety

January 27, 2013

Rigging Safety Selection, Use and Inspection of Slings Workers involved in hoisting and rigging must exercise care when selecting and using slings. The selection of slings should be based upon the size and type of the load, and the environmental conditions of the workplace. Slings should be visually inspected before each use to ensure their […]

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Examples of cranes throughout history

January 17, 2013

Simple cranes have been around for thousands of years. The ancient Egyptians employed wooden called ‘shadufs’ to raise irrigation water from the Nile and some archaeologists believe similar devices were used in the building of the pyramids.

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Properly maintaining your lifting equipment

January 17, 2013

While a crane is a modern engineering marvel, it is also a potentially dangerous piece of equipment that needs to be kept in optimum condition for the safety of those who work on and around it. The crane operator is responsible for inspecting and maintaining the crane in a safe condition, assisted by those with […]

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Lifting Crane Safety Standards

January 16, 2013

OFTEN the most visible pieces of equipment on a construction site or in a factory, cranes also have the potential to be the most dangerous, with accidents resulting in extensive damage to equipment and workers. To better ensure the safe operation of lifting equipment, the AS 2550 series of Australian Standard for Cranes, hoists and […]

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