Course Introduction
 
Steel is a useful material in the construction industry. It has advantageous propertie, including high strength to weight ratio and high ductility. Its most disadvantageous property is its high cost.
 
A design philosophy is needed to ensure that steel used in construction is very safe and economical. This design philosophy is called the limit state design philosophy. 
 

Introduction to Design of Steel Structures

 
Steel is much stronger than conventional construction material like concrete.  Even though steel is costly, steel is preferred to other building materials. The design of steel structures is done in a cost-effective way so the cost is minimized without compromising safety.


 
Steel structures have these types of members: Beams, Columns, Floors, Bracing systems, foundation, and connections.
 
Codes are required while learning the design of steel structure. The code in use today is the IS 800-2007. This is the code of practice for general construction in steel, in which the limit state design method has been followed.
 

Steel as a Structural Material
In comparison to other building materials, steel design has better quality control, is lighter, faster to erect, less material handling at the site, large column-free space, less percentage of floor area occupied by the structural element, and better ductility.
Steel is an alloy that mainly contains iron and carbon. Apart from the carbon, a small percentage of manganese, silicon, phosphorus, nickel, and copper are also added to modify the specific properties of steel.
The most important mechanical properties that are frequently used in the design of steel structures are: Ultimate stress, yield stress, and minimum percentage elongation.
Limit State Design
The working stress method and ultimate strength method are part of the old design philosophy. The design that is now in use is the Limit State Design Method.
The Limit State of Strength depends on stability, fatigue, and plastic collapse. It is associated with failure of the structure under the worst possible combination of load along with proper partial safety factor.
The Limit State of Serviceability is associated with the discomfort faced by the user while using the structure.
In the 2007 Indians code of practice for general construction, the loads/action that can act on a structural system is classified into:- Permanent action- Variable action- Accidental action.
In the case of steel structure, wind load is a factor for designing the steel members because the steel structures are light in weight, so it is vulnerable to cyclones and wind.
Introduction to Connections
Connections are essential in assembling the steel sections/members to build a complete structure. Types of connection:- Rivet connections- Bolt connections - Weld connections
Nowadays riveting connections are becoming obsolete, mainly because of its noise, generation of heat, and difficulty to change the improper insertion of the rivet.