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Pinned rotation from a bolted connection to base plate

Pinned rotation from a bolted connection to base plate

Pinned rotation from a bolted connection to base plate

Baseplates are usually bolted such that the bolts see no movement outside of that due to strain. I have a project where I require little to no moment transfer to the connection and do not have room for a conventional pin. I understand that a simple connection could be made for an 'effective' pin - similarly the baseplate could be relatively thin to allow for elastic deformation, but I am uncertain as to when pinning action occurs.

I have been advised that I could use a conventional 4 bolt anchor pattern and use rubber washers or a rubber pad with the stiffness and thickness sized to ensure the rotational stiffness is less than what would be allowable. On first thought, this makes sense - the plates will be free to rotate by a calculated amount in relation to the amount of applied moment.

However now I have bolts that are separated from mating plates by a gap (thickness of rubber) and these will see some level of bending. Additionally, bolted connections are often tightened to a slip critical state. This will not occur in the conventional fashion.

I have not seen this type of configuration before and am naturally uncomfortable about this.

I would like to know if rubber washers or a rubber pad has been successfully/appropriately used for large civil structures for this type of application.

Along this line of thinking: outside of uplift, is there a problem with not fully fastening down a baseplate to allow rotation?

RE: Pinned rotation from a bolted connection to base plate


You might get some response if you provide more information and a sketch of what you are trying to achieve with loads , bolt sizes etc

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

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