Structural art: John S. Eastwood and the multiple arch dam

In his landmark book The Tower and the Bridge, engineering professor/historian David Billington proposes the concept of ‘structural art’ and, with a focus on bridges, thin shell roofs and tall buildings, describes its relationship to the ideals of efficiency, economy and elegance. Dams are not discussed in The Tower and the Bridge, apparently because the massive gravity designs commonly built for major projects represent bulky, inefficient designs. Moving beyond gravity dam technology, this paper explores how John S. Eastwood's work designing multiple arch dams accords with Billington's idea of structural art. Eastwood built the world's first reinforced concrete multiple arch dam at Hume Lake, California in 1908 and during the last 15 years of his life became a prominent proponent of the technology. Eastwood's designs, how they correlate to the ideals of efficiency, economy and elegance, and how he integrated mathematical theory into his design methodology comprise the focus of this paper. In addition, issues of visual appearance and their effect upon professional acceptance of Eastwood's design are also considered. By employing the concept of structural art as a prism for studying multiple arch dams, the article elucidates an important aspect of hydraulic engineering history.