Using friction to transfer shear to foundation

[tdunaway]

Does anyone know if it is acceptable to use friction to transfer shear from an equipment skid base to its foundation? (i.e. in lieu of anchor bolts or shear lugs)

Thanks

 

[JedClampett]

We usually don't allow it if the shear is due to wind or seismic. We want a positive attachment.

 

[dcarr82775]

For equipment skids, the anchor bolts are often cast into the foundation with a free length. After the equipment is set and grouted in place the anchor bolts are tensioned. The idea is to provide enough normal force (through the tensioning) to take all the lateral forces through friction.

I would never ever just set the equipment and hope it stayed in place on its own.

 

[wannabeSE]

ASCE 7-05 prohibits using friction produced by the effects of gravity for seismic anchoring of components. See section 13.4.

 

[tdunaway]

Thanks everyone. That was my initial reaction when the contractor said that it was his regular practice to set generator engines without anchor bolts, but I wanted to get some other opinions and recommendations before I replied.

Any additional cited references would be welcome.

Thanks Again,
TDunaway

 

[weab]

dcarr,

After concrete creep, wouldn't the tension you applied be relaxed? I think that anchors can take shear, but I question the long term ability of anchor tension.