Sunday, August 5, 2007

A Finer Focus: Bridges of Sacramento County

In the wake of last Wednesday's tragic bridge collapse in Minneapolis, questions abound over the reliability and prevelance of Truss-style bridges throughout the country. At this time, 75,000 or 13.1 percent of the nation's bridges, are designated as "structurally deficient," a status given to the I-35W Bridge as far back as 1990. California ranks seventh out of the nation's 50 states with the most bridges showing structural problems at 13 percent, while Oklahoma is first on the list with 26.8 percent of its bridges standing "deficient."*
How many Truss bridges does Sacramento have? The Fair Oaks Bridge is a Truss bridge, as is the "I" Street Bridge (see photo). According to the Sacramento Bee*, however, Sacramento County's only questionable spans are two, and neither is a Truss bridge: "1923 'bascule' bridge that opens for ship traffic on Highway 160 over the Sacramento River, and a 1949 'lift' bridge that also opens to ship traffic on Highway 160 over Three Mile Slough." Their inspection comes as part of a national alert and will be supervised by Caltrans.

*"'Deficient' but unfixed 1990 probe saw flaw; Caltrans checking similar spans Immediate inspections in California," by Carrie Peyton, et al. Sacramento Bee, August 3, 2007, section A1.

Please refer to the list of sources below on the basics of bridge building and local bridge history:


Historic civil engineering landmarks of Sacramento and northeastern California / prepared by the History and Heritage Committee, Sacramento Section, American Society of Civil Engineers. [Sacramento, Calif.] The Society, [1976].

The bridges of Sacramento / by Bill and Beverly Webster. Sacramento : Sacramento County Office of Education, 1978.

Additional Subject Heading: Bridges Design and construction

Environmental Impact Reports:

Web Sites:

Truss Bridge Laboratory at the University of Florida:

Truss Bridges Descriptions and Photos (Portland, OR) from Texas A&M University:

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