Award of Excellence: Transportation Category
Conde McCullough Bridge Repair - South End
Coos Bay, Oregon
Submitted by BASF Corporation-Building Systems
Great Western Corp.
North Bend, Oregon
BASF Corporation-Building Systems
The Conde McCullough Bridge is arguably the most exquisite showpiece in a series of historic coastal bridges along U.S. 101, the Pacific Coast Scenic Byway. The 5305 ft (1617 m) steel cantilever truss bridge was the longest structure in Oregon’s highway system when it was constructed. Bridges by Conde B. McCullough are strongly influenced by art deco, with ornate detail throughout the bridge. The fear of the loss of the structures due to deterioration compelled the Oregon Department of Transportation (DOT) to make fundamental changes to its approach to historic bridge preservation.
Over time, the elements had significantly deteriorated the bridge and Oregon DOT discovered that a large number of repairs were required to restore the bridge. The bridge required a versatile material that would adhere to the substrate, was compatible with the resistivity of the original concrete, and could be placed in both shallow and deep applications in very confined areas.
Compatibility of the resistivity with a concrete that was laden with 80 years of marine salt was obtained by adding table salt to the repair mortar under the supervision of Oregon DOT.
A Kenrich, diaphragm-type, hand-operated grout pump was used. After placing these portable pumps on tight scaffold areas, the material was pumped full depth both vertical and overhead, where complex forms could be assembled to recreate the original art deco design of the bridge. The ability to be able to form these repairs and pump the repair mortar inside the forms has proved to be one of the main keys to success.
To address the severe weather conditions, a resilient, movable enclosure was built to create work platforms with multiple levels. Once the work was completed in the section covered by the enclosure, it was disassembled, moved, and reassembled to address the next section of the bridge to be restored.