Mission Bay in San Francisco City and County, California — The American West (Pacific Coastal)
Peter R. Maloney (4th Street) Bridge
Photographed By Andrew Ruppenstein, December 17, 2020
1. Peter R. Maloney (4th Street) Bridge Marker - first panel
Inscription.
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 earthquake. The current load requirements are 100 times greater than the original load criteria for which the bridge was designed.
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)
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 earthquake. The current load requirements are 100 times greater than the original load criteria for which the bridge was designed.
City engineers determined that a reduction in the weight
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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. A significant historical date for this entry is October 17, 1989.
Location. 37° 46.515′ N, 122° 23.55′ W. Marker is in San Francisco, California, in San Francisco City and County. It is in Mission Bay. Marker is on 4th Street, on the right when traveling north. Touch for map. Marker is in this post office area: San Francisco CA 94158, United States of America. Touch for directions.
Other nearby markers.
Photographed By Andrew Ruppenstein, December 17, 2020
2. Peter R. Maloney (4th Street) Bridge Marker - second panel
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.)
Photographed By Andrew Ruppenstein, December 17, 2020
3. Peter R. Maloney (4th Street) Bridge Marker - wide view
The marker panels are located along the pedestrian passageway on the east side (bay side) of the bridge.
Photographed By Andrew Ruppenstein, December 17, 2020
4. Peter R. Maloney (4th Street) Bridge - looking south along 4th Street.
Photographed By Andrew Ruppenstein, December 17, 2020
5. Fourth Street Bridge - looking east from Mission Creek Park
Credits. This page was last revised on February 7, 2023. It was originally submitted on December 17, 2020, by Andrew Ruppenstein of Lamorinda, California. This page has been viewed 417 times since then and 56 times this year. Photos:1, 2. submitted on December 17, 2020, by Andrew Ruppenstein of Lamorinda, California. 3, 4, 5. submitted on December 18, 2020, by Andrew Ruppenstein of Lamorinda, California.
