Structural Steel

There are a large number of major buildings where steel is extensively used. They are 

• Industrial and very tall residential buildings, 
• Large span structures, e.g. suspension bridges, railway bridges etc., 
• Towers and water tanks, and 
• Large span roofs for auditorium and warehouses. 

It is fairly easy to estimate the quantity of structural steel due to the following reasons : 

1. Only standard sections of limited sizes are manufactured and their linear weight is known. 
2.  Invariably, the structural drawings are made to a high degree of accuracy and detail, enabling the estimator to directly work out the quantity of structural steel used. 

Standard structural  steel sections consist of angles (equal and unequal), channels, beams, plates, flats and ropes. Steel structures are fabricated by cutting and shaping these sections and joining them by welding or bolting or riveting. This process is known as "wrought and put up" in estimating parlance. The estimator arrives at the total weight (tonnage) of steel used. This is done by just  multiplying the length of the structural steel sections by their respective linear weights as done in the case of reinforcing steel. In case of plates - (Area of plates used x weight/unit area) will give the quantity. 

In measuring jointed frame, full length of structural sections out of which site lengths are fabricated shall be considered. Similarly, in case of plates, e.g. gusset plates, full size of plates (rectangular or square), out of which odd shapes are cut, shall be measured. 

Normally, all structural steel is painted with a coat of red oxide primer - number of coats depending upon the degree of protection required. if needed one or two coats of enamel/ aluminium paint is given as further protection from corrosion. Painting is measured on area (m2) bass.