What Are Reasonable Span of Various Materials
The allowable span which a carrier can have so that it will not collapse depends on three things (for an overwiev see figure 1):
+ its cross-section geometry (see examples below in the geometry part)
+ its material (steel, wood or reinforced concrete)
+ on how you will apply the load on it (is the weight in the middle of the carrier or at one side)
Remember: NEVER use concrete or similar materials like stone without reinforcements of steel or similar for a carrier! The possibility that it will colappse is almost certain!
You can see an overview of a common problem involving a carrier as it would be used for a roofing or for hanging other loads for instance meat.
Simplified carrier.jpg
to be CONTINUED........
--HTP Petros 15:57, 13 January 2010 (UTC)