: Number of from supports (typically 3 for a pin and roller) , the truss is determinate and ready for analysis. Step-by-Step Calculation Procedure 1. Solve for External Reaction Forces Treat the entire truss as one rigid body. Draw a Free Body Diagram (FBD) of the whole structure.
Select a joint with at least one known force and no more than two unknown forces. Draw an FBD of that specific joint. 2.1.7 calculating truss forces