The member design  and code checking in STAAD.Pro are based upon the allowable stress design method as per IS:800 (1984). It is a method for proportioning structural members using design loads and forces, allowable stresses, and design limitations for the appropriate material under service conditions.

It is not practical to describe every aspect of IS:800 here. This section, however, will discuss the salient features of the allowable stresses specified by IS:800 as implemented in STAAD.Pro. Appropriate sections of IS:800 will be referenced during the discussion of various types of allowable stresses.