History and Esthetics in Suspension Bridges

The George Washington Bridge raised two fundamental problems in the history and esthetics of bridge deisgn: (1) The relationship between esthetic preference and structural performance; and (2) the relationship between the architecture of bridges and their engineering. The first relationship was put in terms of the flexible deck: the George Washington Bridge, as originally complete in 1931, had almost no vertical stiffness. The second relationship arose in the design of the towers, for which architectural plans envisioned masonry forms while engineering requirements dictated a steel structure. Thus, that design followed from two questionable assumptions: (!) The deck could be without vertical stiffness; and (2) the steel towers should be civered with a masonry façade. The first led directly to the failor of the Tacoma Narrows Bridge in 1940, and the second carried forward the idea that in large-scale structures, the engineering form needed an architectural façade to be elegant.