ABSTRACT
This chapter discusses the study of truss girders with simply supported spans. The static method of construction of influence lines consists in using the relations obtained for a sought force from statics equations and applying the named general property for trusses. The methods of moment point and projections are most applicable, because constructing influence lines on their basis requires only a few rules. The consecution of construction of an influence line is the same for both the method of moment point and the method of projections; first, the left and right branches are drawn, using the known ordinates under supports and considering the mutual disposition of branches. In the case of complex trusses, construction of influence lines may be done by the method of substitute members.
