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/335723
PROJECT Spanish Creek Bridge An open-spandrel arch By David Clark, California DOT PROFILE SPANISH CREEK BRIDGE / KEDDIE, CALIFORNIA BRIDGE DESIGN ENGINEER: California Department of Transportation, Sacramento, Calif. PRIME CONTRACTOR: C. C. Myers, Rancho Cordova, Calif. OTHER MATERIAL SUPPLIERS AND CONSULTANTS: Foundation report, Kleinfelder, Sacramento, Calif.; Temperature monitoring system, Engius IntelliRock, Stillwater, Okla.; Concrete cooling system design, CTLGroup, Skokie, Ill.; Piling contractor, Drill Tech Drilling and Shoring Inc., Antioch, Calif.; Tieback contractor, Neil’s Controlled Blasting, Newcastle, Calif. PROJECT DESCRIPTION: 630-ft long, seven-span, open spandrel arch supporting a conventionally reinforced, cast-inplace concrete, box girder A new, open-spandrel arch bridge located in the Sierra Nevada mountains of California now becomes the latest major structure to be constructed in the Feather River Canyon. This rugged and scenic canyon has been designated a historic district as well as a National Scenic Byway. It is the home to numerous railroad and highway bridges, tunnels, retaining structures, and hydroelectric facilities, many of which are also designated historic structures. The graceful lines of the new Spanish Creek Bridge will do well to complement this setting. The Spanish Creek Bridge and State Highway 70 provide a primary route in and out of Quincy, a logging town 10 miles to the south of the bridge. Because there are few alternative routes in this area of the Sierra Nevada Mountains, the Spanish Creek Bridge is critical to local traffic and the economy. New Bridge Needed The Spanish Creek Bridge cost approximately $29 million dollars to build and marks the 11,000th transportation project funded by the American Recovery and Reinvestment Act of 2009. It replaces a bridge that was built in 1932, which had two 12-ft-wide lanes with no shoulders. After 80 years of service, the existing bridge was beyond its expected service life and was becoming increasingly expensive to maintain. It was located in an active seismic area but it did not meet modern seismic criteria. The new structure is on a tangent with a grade sloping downward to the north at just over 2%. It is a conventionally reinforced concrete box girder capable of supporting oversized loads up to 360,000 lb, whereas the load limit for the old bridge was set at 80,000 lb. Rising to a height of approximately 170 ft over Spanish Creek, the bridge length is 630 ft. The 350-ft-long arch span is one of the longest conventionally reinforced spans in California. The bridge deck is 43 ft wide, which includes two 12-ft-wide traffic lanes and two 8-ft-wide shoulders. The solid twin arches are approximately 8 ft square at the base and taper gradually in depth to 5.5 ft at the crown. The spandrel columns are solid with outside dimensions of 4 by 5.8 ft and tapering to 4 by 4 ft at their tops. They vary in height from 83 ft at the ends of the arch to 10 ft at the center of the arch. The superstructure consist of cast-in-place multicell (fivecell) reinforced concrete box girders with span lengths of 74 to 95 ft. (continued next page)