Peter R. Maloney (4th Street) Bridge
Operation of the Fourth Street Bridge
The Peter R. Maloney Bridge, otherwise known as the Fourth Street Bridge, opened in 1917 after a two-year period of construction. Joseph B. Strauss, the leading designer of bascule bridges in the United States in the early twentieth century, designed the drawbridge portion of the bridge. Strauss is most well known in San Francisco as a promoter and design collaborator on the Golden Gate Bridge. In 1985 the bridge became eligible for listing on the National Register of Historic Places. In 1980, the Fourth Street Bridge was renamed for Peter Maloney, a San Francisco police officer who helped troubled boys. The bridge is the oldest operating bascule bridge in the state.
Seismic Retrofit
Following the Loma Prieta earthquake of October 17, 1989, the California nia Department of Transportation greatly accelerated their bridge seismic retrofit program. During the evaluation of the Fourth Street Bridge they determined that the 1.4 million-pound overhead counterweight was particularly susceptible to seismic activity. It could create a catastrophic failure in the event of a major
City engineers determined that a reduction in the weight of the overhead counterweight would significantly reduce the risk of the bridge contortion and damage during a seismic event. The counterweight, however, is a key design element of the historic bridge. To increase the strength of the bridge while retaining its historic character, engineers conceived of a lighter overhead counter-weight working in conjunction with a hidden underground counterweight. The new over- head counterweight weighs 100,000 pounds and is only responsible for seven percent of the counterweight function. A new underground counterweight provides the remaining ing ninety-three percent.
The City of San Francisco closed the Fourth Street Bridge between 2003 and 2006 while they completed the seismic retrofitting. The retrofitted bridge appears nearly identical to the historic bridge. The mechanics of the raising and lowering of the bridge are safer, however, since the bulk of the counterweight is now underground.
(Caption describing bridge mechanics not transcribed)
Topics. This historical marker is listed in this topic list: Bridges & Viaducts.
Location. 37° 46.515′ N, 122° 23.55′
Other nearby markers. At least 8 other markers are within walking distance of this marker. Rammaytush (about 700 feet away, measured in a direct line); Chutchui and Sitlintac (about 700 feet away); 150 Years of Service on the Oldest Railroad in the West With Continuous Passenger Service (approx. 0.2 miles away); The Francis "Lefty" O'Doul Third Street Bridge (approx. 0.2 miles away); Juan Antonio Marichal Sanchez (approx. 0.2 miles away); Willie Howard Mays, Jr. (approx. 0.2 miles away); Steamboat Point (approx. 0.2 miles away); Southbeach Shoreline – 1852 (approx. ¼ mile away). Touch for a list and map of all markers in San Francisco.
Also see . . . Fourth Street Bridge (HistoricBridges.org). "This bridge is an early and rare surviving example of a Strauss vertical overhead counterweight type bascule bridge. Designed by Joseph Strauss's company, this bridge represents the design and appearance of this type well, despite alteration. The vertical overhead counterweight type bascule is a lot more compact that the heel-trunnion bascule design that Strauss also designed and can be seen at the nearby 3rd Street Bridge...." (Submitted on December 18, 2020.)
Credits. This page was last revised on December 18, 2020. It was originally submitted on December 17, 2020, by Andrew Ruppenstein of Sacramento, California. This page has been viewed 45 times since then and 11 times this year. Photos: 1, 2. submitted on December 17, 2020, by Andrew Ruppenstein of Sacramento, California. 3, 4, 5. submitted on December 18, 2020, by Andrew Ruppenstein of Sacramento, California.
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