Analysis of Trusses:

The member forces is analysed for the subsequent two conditions:

Dead and Live Loads

These are calculated per square metre of (horizontal) plan area, and acts in a vertical direction at the joints. This is shown in Figure (a).

(a) Live Load and Dead Loads (b) Wind Loads (Wind Blowing From Right)

In this case, the wind is blowing normally to the roof truss. It is calculated per square metre of sloping roof area and is supposed to act at the joints normal to the principal rafter. The member forces will be different for wind blowing from left If the truss is unsymmetrical, , and when it blows from the right (Figure (b)).