Suppose you were making a commercial to convey the sense of aproduct reaching consumers from coast to coast. Which visual images would you choose?
When United Airlines faced that problem a few years ago, it chose the Brooklyn Bridge to represent the East Coast, and the Golden Gate Bridge for the West Coast. That's not surprising. Bridges are among our most celebrated structures. Stretching across Tampa Bay or the Mississippi River, they can become symbols for entire regions.
Our thousands of ''everyday'' bridges are important, too. The bridges on Chicago's Dan Ryan Expressway, for example, are seen by millions of commuters weekly. Collectively, they have a greater impact than any single public building on people's perception of that city.
As any traveler knows, however, many bridges are sadly nondescript. Carrying traffic but lacking grace, they are merely functional.
They could be much more. They should be works of civic art that enliven each day's travel, making all of our journeys more pleasant.
I was among a group of engineers and architects that recently examined bridge design for the National Research Council. We identified a number of examples where engineers are designing bridges that are not only beautiful but reasonable in cost.
Two changes are needed to make such bridges more routine. First, people must insist that their public agencies make good appearance an explicit goal of public works. Second, the engineering profession must improve its ability to respond to that challenge.
When citizens speak up, more attractive bridges often result. In Columbus, Ohio, public interest encouraged officials to organize informal competition to obtain the best possible design for the new Broad Street Bridge. In Tennessee and California, continuing public support has led to a tradition of outstanding bridges. In Maryland, a new three-year program will improve the appearance of state bridges.
Many people think improved aesthetic impact derives from expensive add-ons, such as an unusual color, ornamental features or special materials like stone or brick. But in fact the greatest aesthetic impact is made by the structural components themselves the cables, girders and piers. If these elements are well-shaped, the bridge will be attractive without added cost.
The Golden Gate Bridge, for example, owes its appeal to the graceful shape of its towers and cables, not to its reddish color. If the towers were ugly, painting them red would not make them attractive.
John Roebling, designer of the Brooklyn Bridge, and other notable engineers of the past and present have designed bridges that achieve structural excellence and outstanding appearance at a cost no greater than competing solutions. Their success proves that beauty need cost no more than mediocrity.
The dreariness of many bridges is not due to a lack of good intentions among designers. Most engineers do believe that concern for appearance should be an integral part of their work. But other matters often grab their attention. Engineers respond to the priorities of their clients state highway departments, toll authorities and other public agencies that now give aesthetics too little consideration.
These agencies have the most influence to improve the situation. They set the standards, select the designers and pay for the results, and they should demand more. They would do so if they thought the public expected it. To put it another way, Americans should insist on getting full value for their tax money. They should demand not just bridges but beautiful bridges.
Engineers can meet that demand although, as a group, they have some problems to overcome. Bridge design is an art, one that integrates judgments based on science and mathematics with others based on aesthetics. Many engineers are more comfortable with mathematical formulas than with the imprecision of appearance. Their bridges suffer as a result.
So engineers must expand their skills. The key is to make clear to them that appearance is a criterion equal in importance to performance and cost. Doing so will encourage engineering schools to place greater emphasis on aesthetic concerns and lead engineers to develop their aesthetic abilities in everyday practice.
The engineering challenge of bridges is not just to find the ''least cost'' solution. It is to bring forth elegance from utility. We should not be content with bridges that move only vehicles and people. They should move our spirits as well.
Frederick Gottemoeller is an architect and engineer in Columbia who designs bridges.