Steel materials presently specified for all-welded steel gantry crane girders can differ notably from those used in the past, and welding technology itself has been used extensively only since the 1930s. During the 1950s and ’60s many such structures were constructed using the semikilled carbon steels produced in accordance with BS15, this being comparable to grade 43A steel made to the minimum requirements of BS 4360. Modern usage of these steels is severely constrained by current Codes of Practice for ‘parts in tension’. This can pose a difficult question when the continuing safety of some ageing structures is reviewed.
E.J. Forsey and N.J. Prescott