Briefing: William Fairbairn and the ‘suspended girder’

This briefing introduces the reprint of a classic paper presented to the Institution of Civil Engineers in April 1847 by William Fairbairn. A month earlier, Fairbairn had investigated the cause of a partial building collapse at Ancoats Mill in Manchester in which a mill worker had died. Contemporary newspaper reports on the accident and the inquest are used to put Fairbairn's paper into context. Some background is provided to Fairbairn's serious concerns about the safety of large buildings when not designed and built by competent persons. Much of the discussion at the Institution after presentation of the paper was taken up by the defence by leading railway engineers of the principle of the ‘suspended girder’, a cast iron beam strengthened with wrought iron trussing rods. Fairbairn blamed the mill building collapse mainly on the use of the suspended girder, which at the time was gaining popularity for railway bridges of longer span. The paper explains how events unfolded soon afterwards to prove Fairbairn right and his eminent contemporaries wrong.