What Are Reasonable Spans of Carriers made of Various Materials

At this part a simple example of a carrier which connects one wall of the house with the other as can be seen in figure 1 is presented. For simplicity the carrier is loaded in its middle with a sandbag. Exactly the same loading would be present if the roof was mounted at this point.

Figure 1: An overview of a the most common use of a carrier

For reasons of simplifying future calculations and understanding the above figure 1 is remade and represented as in figure 2

Figure 2: A simplified figure of the previous overview to allow easier calculations

For the start it is Importatnt to remember that the allowable span which a carrier can have so that it will not collapse depends on three important factors:

+ its cross-section geometry (see examples in figure 3 below)

+ 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 an other point)

Remember: NEVER use concrete or similar materials without reinforcements of steel or similar for a carrier! The possibility that it will colappse is almost certain!

Figure 3: An overview of the most common carrier crossections

Notice that from the above mentioned cross-sections geometrys the best choice conserning the weight of the carrier and its resistance to the loading in our case would be to use the "H-shaped" cross-section as for instance one can find in railroad tracks.

to be CONTINUED........ Notice: The author accepts no responsibility for the safety of a construction or the correctness of the article

--HTP Petros 15:57, 13 January 2010 (UTC)