Wind loads on open truss structures: applications of blockage to historic transporter bridges.

The overall aim of this study is to compare and contrast the design of the two remaining working examples of early twentieth-century transporter bridges in the UK, namely, those at Newport and Middlesbrough. With the aid of modern finite-element analysis, the behaviour of the structures under loading is investigated, likely modes of failure determined and the efficiency of each structure evaluated. The important horizontal load component due to wind at the exposed locations of the bridges is examined using 'current blockage', ideas transferred from recent work on wave-current-structure interaction for space-frame structures in offshore engineering. This article is part of the theme issue 'Environmental loading of heritage structures'.