The support component and performance of interisive support with cable and joist,and applicabion of the support to large-span,crossing points and goaf extension of I-bar support are introduced.

Among various steel structures, I-steel beam (H-steel beam) is the most widely used as the main structure of almost all engineering works.

This paper analyzes the shortages of current used design method of I-type steel beam under biaxial bending,and proposes a simple and practical design method through studying the force of this steel beam,in order to popularize steel beam under biaxial bending.

Critical loads calculation for I-beam under combined loads;