oncentric with the girder.
The bridge cost 21.5 million dollars to build (Welch 2003), which corresponds to approximately $12,000 per square metre of deck. In comparison, a vehicular bridge (the piers of which are visible in the figure) built adjacent to the Esplanade Riel Bridge and completed in 2002 cost approximately $5500 per square metre (O’Brien 2001). Assuming that a pedestrian bridge could have been built at a similar unit cost, the premium that was paid for the Esplanade Riel Bridge compared to a low cost option was approximately 12 million dollars. On this basis, we can reasonably conclude that the design of the Esplanade Riel Bridge was not significantly influenced by the discipline of economy.
For these reasons, therefore, it can be stated that the Esplanade Riel Bridge stands outside of the tradition defined by the Salginatobel Bridge. Most of the so-called “signature” bridges that have been built in recent years, examples of which include London’s Millennium Bridge (Dallard 2001) and the Sundial Bridge in California (Brown 2004), likewise stand outside this tradition.
Should we be concerned? None of these bridges could be called a bad bridge. The Esplanade Riel Bridge, for example, is apparently performing its function well and can reasonably be expected to do so for its entire design life. By all accounts, it is well liked by the people of Winnipeg.
What causes concern is not so much the individual bridges, but rather the perspective on bridge design that underlies them, which holds that minimum cost structures cannot be aesthetically significant. If this is true, then aesthetic quality is something that must added to minimum cost structures, and hence will add cost. From a philosophical point of view, this proposition is simply incorrect. The bridges of Maillart provide the definitive counterexample.
From a more pragmatic perspective, it is evident that the conventional wisdom on aesthetics can result in very expensive bridges. This is especially true when the primary means to create visual impact is to arrange structural members so as to produce indirect flows of forces, as was the case in the Esplanade Riel Bridge. When structural systems are determined on the basis of preconceived notions of what will look good, the effect on cost can be significant. When the premium that is paid to create a specific aesthetic statement is in the tens of millions of dollars, one is certainly justified in questioning what was gained for the money spent.
It is difficult to find new opportunities for artistic expression within the discipline of economy when there is no evolution of the underlying technology. The profession has struggled with attempts to improve the aesthetic quality of well established structural systems, with little success. Precast concrete I-girders, for example, are often a cost-effective choice for short-span bridges throughout Canada. Transforming these bridges into works of aesthetic merit, however, is difficult and generally entails increases in cost. If we wish to create opportunities for artistic expression in the tradition of Maillart, then we must acknowledge the role played by technological innovation as a link between economy and aesthetics, and create conditions in which designers can move technology forward.
Designers, owners, and educators all have a role to play in creating the right conditions for innovation. To define what is needed to accomplish this objective, it is helpful to consider the conditions that prevailed during Maillart’s professional life. In this regard, the following points are significant:
Opportunities for innovation. Historically, advances in materials technology have provided the impetus for innovation in structural systems. Maillart’s material was reinforced concrete, which
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