Dynamic Coefficient of Friction for Bay Mud

[MilesofPiles]

Hello Gentleman,

I am trying to determine the loading on a crane while extracting sheets with a vibratory hammer in "Bay Mud" soil.

With static friction no crane would be able to lift the sheets out, but while using dynamic friction I hope to get a better idea of what the loading could possibly be.

Does anyone have any information regarding a similiar situation? Or have a resource for coefficients of friciton for different soil types?

LMI's would also give us the "asbuilt" condition while trying to perform this action but for time/money/production reasons having a better idea before hitting jobsites would be beneficial.

Thanks,

-D.

 

[civilperson]

Maximum equivalent static loading is 3-5 times the weight of the vibratory rig with piling. (Use SF on this amount of 1.5-2.0 for rigging, pad pressure, etc.)

 

[dgillette]

Is 'dynamic coefficient of friction' even the right strength concept for Bay Mud? Looks to me more like a problem of undrained strength of a plastic clay.

 

[vulcanhammer]

One thing you need to take into consideration is the suspension (pulling) capacity of the vibratory hammer. With some "factor of safety" for dynamic effects (which depend upon the configuration, natural frequency of the suspension and other factors), the force with which the crane pulls the hammer cannot exceed the sum of the static weight of the system, the dynamic weight and the maximum static pulling capacity of the suspension.

If you get on the job and the hammer is unable to extract the piles even when putting the suspension in "full tension," then your hammer is too small.

Additional information on vibratory hammers can be found at

http://www.vulcanhammer.net/vibro/index.php