THE CONCRETE BRIDGE MAGAZINE

SPRING 2008

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.

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42 | ASPIRE , Spring 2008 A E S T H E T I C S C O M M E N T A R Y by Frederick Gottemoeller to be a very durable and long-lasting bridge due to the prestressing and high strength concrete." Local agencies and the public have also been receptive to the new structure and are looking forward to the day later in 2008 when the bridge will be opened to traffic completing the first phase of the 'Entrance to Aspen.' _____________________ Thomas W. Stelmack is Senior Project Manager with Parsons, Denver, Colo. The new Maroon Creek Bridge and the former railroad trestle that it replaces present a fascinating contrast in bridge design phi- losophies. Happily, both will remain in place to remind engineers that there is always more than one way to bridge a gap. The original rail- road bridge crosses the valley with 19 spans supported by multiple thin steel piers. It achieves transparency because the members are so thin that you can see right through them. The new bridge crosses the valley with three spans on two massive piers. It achieves transpar- ency because you can see between them. Even non-engineers will fnd the differences between these bridges interesting and worth thinking about. When the railroad bridge was converted to automobile use in 1929, diagonal struts were added at each pier line and gave the cross sec- tion a pinched-waist silhouette. The new bridge takes this silhouette as a point of departure for the design of the new piers. This very ef- fectively provides a visual tie between the bridges in spite of the fact that they are otherwise quite different. The long deck overhangs are another successful feature of the new bridge. Their shadows on the girder webs reduce the apparent depth of the girder. At the same time, the deep setback of the girder webs from the edges of the deck reduces the shadow of the bridge on the ground. The piers them- selves appear heavy, particularly when seen together with the thin steel members of the original bridge. They would have been improved with thinner proportions, especially at the "knuckle" just below the girder. However, overall this is a fne bridge. The crossing of the creek by State Highway 82 will continue to be a memorable feature of the Maroon Creek valley. Only the final closure segment to the abutment remains as the form travelers are lowered to the ground near the pier. For more information on this or other projects, visit www.aspirebridge.org. ASPIRE_spring08.indb 42 3/24/08 1:06:42 PM

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