D6.A.1 General Comments

The design philosophy embodied in this specification is based on the concept of limit state design. Structures are designed and proportioned according to the limit states of which they would become unfit for their intended use. Two major categories of limit-states are recognized: ultimate and serviceability. The primary considerations in ultimate limit state design are strength and stability; that in serviceability is deflection. Appropriate load and resistance factors are used so that uniform reliability is achieved for all steel structures under various loading conditions and at the same time the chances of limits being surpassed are acceptably remote.

In the STAAD.Pro implementation, members are proportioned to resist the design loads without exceeding the limit states of strength, stability and serviceability. Accordingly, the most economic section is selected on the basis of the least weight criteria, as augmented by the designer in specification of allowable member depths, desired section type, or other related parameters. The code checking portion of the program verifies that code requirements for each selected section are met and also identifies the governing criteria.

The next few sections describe the salient features of STAAD.Pro implementation of "Design Rules for Structural Steelwork." A detailed description of the design process, along with its underlying concepts and assumptions, is available in the specification document.