K-10000 tower crane
ROTATING BASE

 

THE SHORT STORY:
The tower rotates at the Base in order to always have two mast corners evenly sharing the compressive loads due to moment.

 

THE LONG STORY:

Tower cranes, in the capacity range normally encountered, and at maximum free standing height, develop their maximum Design Base Moment not in service due to Hook Load, but rather out of service due to Design Wind Load, typically 100 M.P.H.

The max. Moment in such tower cranes is generally several times greater at the Base than at the top of the tower.

In the K-10000 tower crane, the Moment due to Hook Load is all dominating, while the Moment due to Wind is insignificant.  Consequently, the moment in the tower is virtually the same from Top to Base.  

When a tower crane rotates at the top, as almost all do, and when the Jibs are diagonal to the Tower, there is only  one Mast Corner Leg to carry the Compressive Load due to Moments.

 Placing the Swing Ring at the Base of the K-10000 does not result in a Swing Ring cost penalty, but the Tower  now rotates with the Jibs, so there are always two Mast Corner Legs evenly sharing the maximum Compressive Loads.


 

 

 

 

 

 

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Copyrightę 1999 Tower Cranes of America, Inc.
Page Last Updated On 09/13/1999