Aesthetic Guidelines for Older Bridges

Abstract

As the nation's infrastructure ages, many older bridges face rehabilitation or replacement. Many of these structures have historical significance, and others have become community landmarks. Distinctive metal truss bridges and various concrete arch bridges still grace the nation's highways, but they are rapidly disappearing because they cannot meet the safety requirements of modern highway usage. As a result, where roadway and river crossings were once defined by expressive, sometimes monumental spans that made the passage truly an experience, travelers now speed efficiently over unobtrusive structures, often unaware they were ever on a bridge. Engineers are becoming increasingly aware of the undercurrent of public sentiment for preserving these links to the past. Opposition to replacement can delay needed improvements for months and even years, but it can be overcome by incorporating the existing bridge into alternative solutions that meet both the functional needs and the aesthetic desires of the community. When an older bridge is to be part of the new crossing solution, what are the aesthetic considerations for the bridge designer or the project manager? The aesthetic impact of various alternative solutions involving older bridges is discussed, including compatibility of parallel structures when different bridge types are involved, importance of viewpoints, and aesthetic impact of various preservation measures such as cathodic protection. In addition, guidelines are provided and examples of various solutions are shown.