1998 Structural Engineering Traveling Fellowship
Bridges as Engineering Accomplishments and Artistic Statements

When people think of architecture, images of houses, museums, or churches are conjured in their minds—images of buildings. Rarely do they link the elegance of architecture with the design of bridges. But why? Bridges, just as buildings, should be thought of as a work of art, incorporating elegance, utility, economy, and safety. In the field of bridge design, it is laid in the hands of the engineer, not the architect, to create such a vision and to integrate all aspects of the project to build not only a bridge, but also a work of art.

The idea of bringing together art and science in bridge engineering continues to make its impact around the world. The technology and innovation available today in bridges, such as cable-stayed bridges, composite materials, and prestressed concrete, opens the door for new possibilities in structural architecture. These possibilities have been realized by many European countries, Japan, and the United States. There are however, few signature bridges of architectural importance in the United States. Cable-stayed bridges are only a recent addition to the infrastructure of this country. The United States needs to follow the European and Japanese trend and emphasize to engineers that they do have choices in the aesthetics and form of a bridge.

Artistic vision can be incorporated into any type of bridge, whether it is an arch, a suspension, a concrete box girder, etc. Cable-stayed bridges, however, possess great flexibility in their aesthetic features. Artistic shaping is maximized through different tower types and geometries, various positioning of the cables in one or multiple planes, and the arrangement of cable, i.e., fan or harped. The architectural capabilities of cable-stayed bridges are brought to an extreme by the Ruck-A-Chucky Bridge, an unbuilt vision by T. Y. Lin.

Cable-stayed bridges offer an engineering challenge in addition to the artistic challenge. New methods of construction have been used to build these bridges, which tests the design and feasibility of the structure. For example, the Chesapeake & Delaware Canal Bridge was constructed by cantilevering off of each pier. This allowed barges to continue to use the canal during construction. Challenges are also presented in the engineering design issues of this type of bridge. Dynamic vibrations were a problem on the Erasmus Bridge just last year. The design of cable-stayed bridges is an exciting task, which tests the engineer’s ability in a way that more traditional bridges don’t anymore.

Many engineers have captured the artistic vision, while juggling the more practical issues of constructability, economy, and safety. Christian Menn, designer of the Ganter Bridge in Switzerland, innovatively combined the cable-stayed bridge with the technology of prestressing. This unique bridge is visually stimulating against the snowcapped Swiss Alps. The sleek, solid lines of this bridge and the design issues of an S-curved roadway make this bridge a definite accomplishment in the name of structural architecture.

Bridges can be incorporated to fit the environment, as is the case with the Saint Nazaire Bridge in France. Through color and the triangular form of the cables, the bridge blends with the backdrop of ships on the waters below.

The new technology of advanced composite material bridges also presents opportunities for engineers to shape the future of bridge design. These new materials, having properties that far exceed those of present-day materials, will expand the limits on bridges, structurally and artistically. Greater span lengths, more slender piers, and greater variations of cable configurations are only some of the things that can be realized with this new material. The options will only be limited by a narrow vision. Therefore, it is important for engineers to see the possibilities and not design based on a “cookbook” criteria, where every bridge looks identical.

It is an exciting time for the bridge engineer. Equipped with artistic expressions in bridges from the past, and new innovative technologies, materials, and construction methods, the possibilities are endless. This is the civil engineer’s opportunity to shape the world of bridge design and to get the worlds’ attention, just as Frank Lloyd Wright did with buildings. Engineers need to know it is their job to not only consider the utility, safety, and constructability issues, but also to bridge the gap between art and science.