Measuring structural steel for RA bills

Unit of measurement

Structural steel work is measured in kg. Structural steel is measured by weight: length of each member times the standard weight per metre of its section, plus plates by area and thickness.

The BOQ item description decides the unit and what the rate includes. Where the BOQ and this guide differ, the BOQ and the contract's mode of measurement win.

What is measured

• Length of each member from the fabrication drawing, end to end.
• Weight per metre of each rolled section, from the section tables the contract adopts.
• Plates, gussets and cleats by their area times thickness times the density of steel.
• Bolts and welds only where the BOQ measures them separately.

Standard deductions

• Cuts, notches and holes are commonly not deducted, as per the contract's mode of measurement and the relevant part of IS 1200.
• Rolling margin and wastage are part of the rate.
• Painting and erection are measured under their own items if the BOQ separates them.

Worked example

Industrial shed, portal frame bay one, from fabrication drawing F-03. B is the section weight in kg per metre.

Row by row: Columns, ISMB 200, 4 x 6 x 25.4 = 609.60; Rafters, ISMB 250, 2 x 12.5 x 37.3 = 932.50; Purlins, ISMC 125, 12 x 6 x 12.7 = 914.40.

Total: 609.60 plus 932.50 plus 914.40 = 2,456.50 kg. Deductions are entered with negative nos, so they reduce the total in the same column.

Common disputes

• Members are billed on weighbridge weight when the contract pays on section weight.
• Plates and gussets are estimated rather than worked out from the drawing.
• Fabricated members not yet erected are billed at the full rate.

Recording it in Tatha Vastu

Members are entered by mark from the fabrication drawing, with the section chosen from a list that fills in the weight per metre. Fabricated and erected stages can be billed at part rates where the contract allows.

Approved entries are locked, and a correction becomes a new version with its reason. See the measurement book, or use the measurement sheet template if you still keep the register in Excel.