Aesthetics and Economy in Pedestrian Bridge Design

Abstract

Two common pitfalls of pedestrian bridge design are explored: the idea that a structure that is efficient will automatically be elegant versus the notion that a lot of money must be spent to get a beautiful structure. The drive for landmark bridges has led some engineers to disregard the engineering ethic of economy with some recent footbridges. The Töss Footbridge by structural artist Robert Maillart is shown as a model structure, with Maillart's calculations and a description of the bridge's structural behavior presented. Then an extremity on the other side of the spectrum is analyzed: the Turtle Bay Sundial Bridge in Redding, California. The cost escalation and a scientific explanation of the irrationality of the bridge form are presented for this $23.5 million footbridge. In order to explore both pitfalls in the United States an informal national study of all 50 states was performed. Results from the national study (including costs) are described and interpreted. Three unique structures from this study are presented which are reasonably economical and prove that a so-called signature bridge does not require extreme cost.