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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 inpidual 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:
1. Opportunities for innovation. Historically, advances in materials technology have provided the impetus for innovation in structural systems. Maillart’s material was reinforced concrete, which was a new material in the early twentieth century. Whereas most of his contemporaries designing concrete bridges used concrete primarily as cast-in-place masonry, Maillart developed structural systems that made effective use of the composite material’s unique properties, including its capacity to resist tensile and bending stresses. If we are looking for opportunities to innovate in the twenty-first century, therefore, we should look to our own new materials. There is an abundance of new materials available to structural designers, for which suitable structural systems have not yet been developed. These should provide the starting point for designers looking for ways to move bridge technology forward.
2. Designers who can innovate. It is unfair to expect engineers to innovate when their education consists predominately of teaching them how to calculate forces in structural systems made with materials in common use a half a century ago. Maillart’s teacher at the Federal Institute of Technology in Zurich, Wilhelm Ritter,taught his students how to design in reinforced concrete at a time when this material was still struggling for acceptance (Billington 2003). How many civil engineering programs teach undergraduate students how to design in ultra highperformance concrete, high-performance steel, and advanced composite materials?