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
Combinations and arrangements Everything designed has an element of arbitrariness in its form. Loewy described how groups of his designers used to go about designing a new model automobile. Different groups were given different tasks, such as the front and rear of the car, and the conceptual work began, to be cut off at some predetermined time by deadlines that were imposed at the outset. After a time, there were "piles of rough sketches," and Loewy saw the design proceed as follows: Now the important process of elimination begins. From the roughs, I select the designs that indicate germinal direction. Those that show the greatest promise are studied in detail, and these in turn are used in combination or arrangements with one another. A promising front treatment can be tried in combination with a likely side elevation sketch, etc. From this a new set of designs emerges. These are then sketched in detail. After careful analysis, they boil down to four or five. Raymond Loewy, The Evolution of Useful Things Useless work on useful things drawing