Maximum Load on a Plastic Sheet

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jamesm
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I am going to attempt to use a sheet of HDPE between a concrete footing and the base of a column to allow the column to move with thermal expansion in the structure it is supporting. My question is how can I determine if the HDPE will be crushed by the weight of the column and no longer act as a "bearing". The pressure from the column will be ~140 psi, and the tensile strength of HDPE is 4,000 psi with a Rockwell hardness of [Shore D60-68]. If this material is not strong enough what would be a suitable alternative?
 
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If I decide to stick with the slide bearing idea I will probably use Teflon or UHMW Polyethylene since it has a lower coefficient of friction. I did find that the UHMW has a compressive strength of 3000 psi. The pressure that the column exerts on the UHMW will be ~150 psi so I'm thinking it will be fine, but I'm not 100% sure if pressure from a load is comparable to comp stress.

Thanks for following up.