Steel structures

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• Steel is made from iron (about 98) & main allpying elements of carbon , silicon & manganese . 
• The carbon content in terms of weight ranges from a high of 2.1 % - 0.2 % . 
• The percentage of carbon content determines the grade of steel produced . 
• High levels of carbon increaee the steel 's hardness but reduced its ductility . 

Structural steel 

• Steelwork may be used in building frames , factories , containers , masts , bridges etc .
• Current codes of practice used in malaysia for the design of steelwork are ; 

BS 5950 

Eurocode 3

• Some of the common steel sections are : 

1. Universal beam ( UB) 
2. Universal Column ( UC) 
3. T section ( cut from UB or UC)
4. C Channel 
5. Lipped Channel 
6. Angle ( Equal or Unequal ) 

1. Universal beams ( UB) are more suited as bending ( e.g. beam ) members because of their greater depth & thicker flange than web thickness . it has a high moment of inertia . 1xx
2. Universal colummns (UC) are better suited for axial compression & are used as columns for steel frames . 
3. Rectangular , square & circular hollow sections ( RHS , SHS & CHS ) has a high resistance to buckling . This makes them suitable as columns or compression members or trusses . 
4. Steel sections may be hot rolled or cold formed . 
5. Hot rolled steel are formed from liquid steel melted at temperatures above 1000celcius . 
6. Cold formed steel are formed by the pressing of machinery usually at room temperature . 

Hot Rolled Steel 

• Hot-rolled steel sections are produced in steel mills from steel billets by passing them through a series of rolls at temperatures above 1000 celcius . 
• when steel is heated to the point it is malleable , it is possible to force it through a variety of shapes . This allows the manufacture of UB , UC , C-channel , angles , RHS , SHS & CHS . 
• Most of the structural steel used in buildings in malaysia are hot rolled . 
• Common steel grade is 43A which is mild steel having yield stress between 245-275N/mm2
• Steel grade 43B . 43C , 43D & 43E are also available .All of them have the same yield stress but less carbon content ( with increasing alphabet ) & greater resistance to brittle fracrture . 
• Steel grade 50 ( yield stress 355 N/mm2 ) & 55 ( yield stress 450N/mm2 ) are not common in Malaysia .