This paper describes the design and execution of Broadgate Exchange House, an exciting steel structure in London. This structure uses four tied-arches to clear span an entire office building 78m over a congested railroad track site. An important visual aspect of the building is the use offire engineering principles to allow the perimeter structural steel to be exposed. Special features include redundancy, corrosion protection, behaviour under patterned loads, and buckling analyses. This special structure combines the diverse roles of a bridge and an office building into one system with a clarity of expression which is the focus of the architecture. H. Iyengar, W.F. Baker and R.C. Sinn
To judge from the literature on Roman engineering, there was a time when the history of bridge building was a prominent theme closely associated with a parallel and equally well-developed interest in Roman roads. Recently, as a result of a variety of new approaches to archaeological, technical and social themes, the emphasis has moved to aspects of hydraulic engineering and, in particular, problems of water power and water supply. Of course, fashions in engineering history, Roman or later, are bound to change from time to time. That is understandable and nothing new. On the other hand, any overall view of Roman civil engineering needs to integrate the various approaches, especially in so far as they affect one another. Bridge building, after all, is bridge building, whether the structures are for roads or aqueducts and, in this lecture, both functions will be considered. N.A.F. Smith