VIBRAX®CRANE – Vibration isolation for cranes

Overhead bridge cranes cause noise 

General

Overhead traveling cranes in production facilities adjacent to offices and residential property above industrial space are becoming ever more widespread. Depending on the circumstances, vibrations and noise from crane operations can cause disturbance throughout the building. The type and significance of the disturbance depend primarily on the crane itself. This can limit the extent to which offices and residential property can be used for such purposes, resulting in the loss of rental income or other related costs. 

Similar to disturbances from railway traffic, many of the vibrations that arise during crane movements originate at the rails along which the crane travels. The cause can be a slight unevenness of the rails or worn or dirty wheels. The range of possible excitation frequencies is therefore very wide; the frequency of relevant vibrations on various overhead bridge cranes has been measured by mageba to be as low as 20 Hz.

Damping by the building itself does not suffice

Whether or not the vibrations caused by an overhead bridge crane will be perceived as disturbing in adjacent areas depends on the building’s construction. Depending on stiffness and material, certain frequencies will be better damped than others. It is not possible in practice to predict the transmission characteristics of a building. Unless a building is designed accordingly, its damping characteristics will not prevent disturbance from structurally transmitted noise and vibrations. 

Noise-damping bearing support is required

Reliable prevention of disturbances can only be achieved in practice by elastically isolating the overhead bridge crane from the main structure. Because vibrations from such cranes are generally predominantly in the vertical direction, the vertical connection must be damped to reduce the transmission of vibrations to the building structure. It must be noted, however, that a vertical bearing which offers low dynamic stiffness is also characterized by low static stiffness and will thus experience higher static deformations. The right dimensioning thus depends on an optimal layout of the elastic bearings.

Solution

VIBRAX®CRANE is a specially developed system solution for the vibration isolation of overhead bridge cranes. It consists of a reinforced vibration-damping vertical bearing and an unreinforced vibration-damping horizontal bearing. The reinforced bearings are made of natural rubber (NR), which is known for its excellent damping properties and low compressibility even under high loads.

The VIBRAX®CRANE system enables improvements of 20 – 30 dB to be achieved, depending on the frequency.

The VIBRAX®CRANE system is available for all types of overhead bridge crane, and its supply includes:

• Project-specific design 
• Detailed drawings
• Installation instructions