AD 250: Choice of Steel Sub-Grade

During a recent seminar on the Amendments to BS 5950-1, a straw poll of the (large) audience indicated that only 5% of the structural engineers present specified the steel sub-grade. A further 2% of the audience indicated that they checked that the steelwork contractor chose the correct sub-grade. This left over 90% of the audience who neither specified the sub-grade themselves, nor ensured that others were specifying the correct sub-grade.

The implication of this poll is that there is potential for an inappropriate sub-grade of material used in structures, which could lead to an unacceptably high risk of brittle fracture.

This advisory note serves as a reminder that an appropriate sub-grade must be specified. It should be noted that the requirement to specify an appropriate sub-grade is not new, being covered in BS 5950-1: 1990.

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