The Manning Specification

Robert Manning’s reputation in the field of hydraulic engineering all but eclipses the impact he had on the design and construction of over 128 harbours as Chief Engineer (1874-1891) at the Office of Public Works (OPW) Ireland. His skill in exploiting networks, evident in the development of the Manning Formula for estimating water flow, was equally manifest in his adaptation of concrete to marine works. Though pioneer-ing work with concrete in harbours was underway as early as 1850, by the 1880s little coherence existed in practice. Manning’s earliest concrete harbours, which drew on work by engineering colleagues as well as con-tractors, were no more or less precise. However, the passing of the Sea Fisheries Act (Ireland) in 1883 enabled the construction of a large number of harbours that Manning, in concert with colleagues and contractors, used to develop an adaptable specification governing cement grade, concrete mix and methods of construction.