ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.
Issue link: http://www.aspiremagazinebyengineers.com/i/575053
AESTHETICS by Frederick Gottemoeller In the Summer 2012 issue of ASPIRE, tm I commented on the aesthetics of the I-5 Whilamut Crossing Bridges over the Willamette River in Eugene, Ore. I concluded my comments with "This bridge .... creates a memorable visual effect by contrasting its precise geometry and extreme transparency with its natural surroundings, and by inserting only those few physical elements required to do its job. It is a wonderful expression of what we now can do with the high-performance materials and advanced analytical techniques of the twenty-frst century. Let's hope it becomes a frequently imitated model for the future." With that in mind, it was very rewarding to see the designers apply the same ideas to the north approach structures. Too often owners and designers decide, in the name of saving money, to make the shorter approach spans different structural types than the main spans. On very long bridges, where the approach spans are a tiny fraction of the total length and/or are much lower than the main spans, this may not be noticed. That is not the case for the I-5 Whilamut Crossing Bridges over the Willamette River. The approach spans are a signifcant fraction of the total length and are similar in height to the main spans. Plus, the main spans have a distinctive and attractive appearance. Changing the structural type or especially substituting a mechanically stabilized earth wall would have made for a jarring contrast that would have diminished the original project. Any money saved would have had to be measured against the intangible but real costs of imposing an eyesore on the community. Fortunately, this designer and owner decided to keep the same high quality in the approaches as are in the main spans. "Unity" is an important aesthetic value. It means that all parts of a project that can be seen at one time have a self-similarity such that they appear to have come from the same mind. It may come from a similarity of structural type, of element shapes, of materials, colors or textures, or some combination of the above. (One frequent practice that diminishes unity is mixing different pier shapes in the same bridge.) The clearer and stronger the appearance of unity, the more attractive and memorable the bridge will be. The I-5 Whilamut Crossing Bridges over the Willamette River take advantage of that fact. Frederick Gottemoeller is an engineer and architect who specializes in the aesthetic aspects of bridges and highways. He is the author of Bridgescape, a reference book on aesthetics and was deputy administrator of the Maryland State Highway Administration.