Our resident expert, Cliff Billington is here to answer your burning questions about techniques and correct practices within the concrete industry.
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Cliff,

In the article on "Horseshoe Shims", are the shims plastic or steel?
If plastic can we use as a bedding material and assume 0.6 x fcu for bearing of steel beams and base plates?

Giles Atkinson

 

Giles,

The article does state that the horseshoe shims should be the same material as the bracket against which they bear.
This would (normally) limit the material to steel, either stainless or not.

The main purpose of horseshoe shims is to fit around studding or other obstacles. Whilst it would be possible to use them as the main shims on a horizontal surface, it is far more common to use plain rectangular shims. In this case, if bedded, the limiting bearing stress would indeed be 0.6 x the strength of the bedding material. If the element above the shims was concrete, then a check is also required against 0.4 x the concrete strength.

  
 

 

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