Routine design When we think of bridges, it is the dramatic and monumental long spans that come to mind first, especially the lithe suspension bridges such as the Golden Gate and the pure geometric arches such as Sydney Harbour. But the majority of bridges are not such spectacular structures. Most of them are ordinary overpasses, with spans of 30 or 40 feet, carrying roadways or rails across other thoroughfares or over small streams. You see such bridges by the dozen on any drive down the Interstate. They may be lacking in glamour, but they are more representative of a bridge builder's art. The engineering and construction of girder bridges are pretty routine these days, but the bridges are not quite standard items you order from a catalogue. The girders, whether of steel or concrete, are custom-build for each bridge, then trucked to the site and hoisted into place with a crane. The designer still has scope for variation and creativity, and it shows out on the highways: some overpasses are prettier than others. Brian Hayes, Infrastructure: A Guide to the Industrial Landscape engineeringdesignautomationroutine
Conversational drawing A skilled draughtsman guides design conversations by selecting and emphasizing details in a way that computer programmes cannot. Ron Slade, author of Sketching for Engineers and Architects and a structural director at WSP in London, calls it “conversational drawing”. He notes how botany field guides are always based on detailed drawings rather than photographs — as much for what they leave out as for what they show. “Extraneous material that might exist in a photograph is eliminated. It may be important to pick out and illustrate particular areas and leave other parts in sketchy or broad outline.” Nick Jones, Back to the Drawing Board Why Sketch?