ABSTRACT
In actual structures, the axial and the bending forces, specifically the compression due to gravity loads and the bending due to lateral loads, generally act together. An interaction formula is the simplest way for such cases. In such a formula, the sum of the ratios of factored design load to limiting axial strength and factored design moment to limiting moment strength should not exceed 1. Some members of a structural system are subject to axial tension as well as bending. An example is the bottom chord of a trussed bridge. The hanger type of structures acted on by transverse loads is another example. When an unbraced frame supports an asymmetric loading, the eccentric loading causes it to deflect sideways. First, the frame is considered to be braced by a fictitious support called an artificial joint restraint. Open-web joists are parallel chord trusses where web members are made from steel bars or small angles.
