One of the more important thing in the modeling of steel building its choice of member type ; so how we do this choice ? and under what condition?

The choice depends on the material available in your viscinity.Before you starts your design make a account of the raw materials available in your stock or the most economical sections near your viscinity.You cannot nag for a British or European section which is not available in your viscinty for a small structure.In such a case you should design based on the raw  materials available near you.I hope the answer is up to the question.

The versatility of steel gives architects the freedom to achieve their most ambitious visions. Structural steel is an essential component of most stadia, shopping centres and commercial developments; steel cladding systems adorn iconic, landmark structures worldwide. Steel is one of the most sustainable construction materials. Its strength and durability coupled to its ability to be recycled, again and again, without ever losing quality make it truly compatible with long term sustainable development. Building owners value the flexibility of steel buildings, and the value benefits they provide, such as the light, open, airy spaces that can be created, making it ideal for modernisation, reconfiguring, extending or adapting with minimal disruption, and without costly and sometimes harmful demolition and redevelopment. Even without these benefits, steel is often the first choice on the basis of cost alone. Many of the advantages of steel construction are applicable to all building types and sectors. In this article the case is made for steel construction in nine key areas.