San Diego–Coronado Bridge Explained

San Diego–Coronado Bridge
Carries:5 lanes of
Crosses:San Diego Bay
Locale:San Diego and Coronado, California
Owner:State of California
Maint:California Department of Transportation
Id:57 0857
Winner:1978 World Bridge Beauty Contest
Design:Orthotropic deck on box girder
Material:Prestressed concrete and steel
Length:11179feet or 2.1miles (including approaches)
Width:63feet between curbs
Mainspan:660feet
Spans:32
Pierswater:21[1]
Below:200feet
Builder:Murphy-Pacific
Fabricator:Murphy-Pacific[2]
Begin:February 1967[3]
Cost: million
Open:August 3, 1969
Traffic:75,000 (2009)[4]
Replaces:San Diego and Coronado Ferry

The San Diego–Coronado Bridge, commonly referred to as the Coronado Bridge, is a prestressed concrete/steel girder bridge fixed-link, crossing over San Diego Bay in the United States, linking San Diego with Coronado, California.[5] The bridge is signed as part of State Route 75.

Description

Construction

In 1926, John D. Spreckels recommended that a bridge be built between San Diego and Coronado, but voters dismissed the plan.[6] The U.S. Navy initially did not support a bridge that would span San Diego Bay to connect San Diego to Coronado. They feared a bridge could collapse due to an attack or an earthquake and trap the ships stationed at Naval Base San Diego.[7] In 1935, an officer at the naval air station at North Island argued that if a bridge were built to cross the bay then the Navy would leave San Diego.[7]

In 1951–52, the Coronado City Council initiated plans for bridge feasibility studies.[7] [8] By 1964 the Navy supported a bridge if there was at least 200feet of clearance for ships which operate out of the nearby Naval Base San Diego to pass underneath it.[7] To achieve this clearance with a reasonable grade, the bridge length was increased by taking a curved path rather than a more direct path to Coronado. The clearance would allow an empty oil-fired aircraft carrier to pass beneath itit is not sufficient for Nimitz-class nuclear aircraft carriers in light load condition.[9]

The principal architect was Robert Mosher. Mosher's job was to build a bridge that would provide transportation, allow ships access to the bay, and serve as an iconic landmark for San Diego. Mosher proposed a basic box and girder-style bridge for the framework, with a prestressed concrete and steel deck sitting atop steel girders and supported by towers. Mosher decided to make an orthotropic roadway, which used a stiffening technique that was new to the United States; it increased the strength and resistance of the bridge. As a result, the bridge was strong and eliminated the need for additional superstructures over the deck to disperse weight.[10] [11]

Construction on the San Diego–Coronado Bay Bridge started in February 1967. The bridge required 20,000 tons of steel (13,000 tons in structural steel and 7,000 in reinforcing steel) and 94,000 cubic yards of concrete. To add the concrete girders, 900,000 cubic yards of fill were dredged, and the caissons for the towers were drilled and blasted 100 feet into the bed of the bay.

The bridge opened to traffic on August 3, 1969, during the celebration of the 200th anniversary of the founding of San Diego.[8] [12] The 11,179-foot-long (3,407 m or 2.1 mi) bridge ascends from Coronado at a 4.67 percent grade before curving 80 degrees toward San Diego. It is supported by 27 concrete girders, the longest ever made at construction time.[7]

In 1970, it won an award of merit for a long-span bridge from the American Institute of Steel Construction.[13] The five-lane bridge featured the longest continuous box girder in the world until it was surpassed by the Shibanpo Yangtze River Bridge in Chongqing, China in 2008.[14] The bridge is the third largest orthogonal box in the countrythe box is the center part of the bridge, between piers 18 and 21 over the main shipping channel.

Tolls and tollbooths

Originally, the toll was $0.60 in each direction. Several years later, this was changed to a $1.00 toll collected for westbound traffic to Coronado only. Although the bridge was supposed to become "toll-free" once the original bridge bond was paid (which occurred in 1986), the tolls continued for sixteen additional years. On June 27, 2002, it became the last toll bridge in Southern California to discontinue tolls, despite objections from some residents that traffic to the island would increase.[15] [16] The islands upon which the toll booths sat, as well as the canopy over the toll plaza area, are still intact, located at the western end of the bridge in the westbound lanes. Though tolls are no longer collected, beginning February 19, 2009, there was talk of resuming westbound toll collection to fund major traffic solutions and a tunnel.[17] However nothing came of the discussions, and more recently there have been discussions of removing the unused toll plaza completely.[18]

Lanes and traffic

The bridge contains five lanes: two eastbound, two westbound, and a reversible middle lane with a barrier transfer machine system installed in 1993, which can be used to create a reversible lane in either direction in response to traffic volume. Before installation of the barrier, moveable cones were used to separate eastbound/westbound traffic. On December 7, 1981, Coronado resident Hal Willis was westbound when a drunk driver traveling eastbound at high speeds drove through the cones, hit him head-on, and caused his death. This incident began the process of implementing the barrier solution. The eastern end of the bridge connects directly to a T interchange with Interstate 5, just southeast of downtown San Diego. It is designated and signed as part of California State Highway 75. The bridge was designed entirely and exclusively for motor vehicle traffic; there are no pedestrian walkways, bike paths, or shoulders ("breakdown lanes"). Once a year, beginning in 1986, a lane was opened to pedestrians for the Navy Bay Bridge Run/Walk, a fundraiser sponsored by and benefiting the Navy Morale, Welfare, and Recreation program.[19] Beginning in 2008, cyclists have the once-a-year opportunity to ride over the bridge in the Bike the Bay "fun ride".[20]

Artwork

The pillars supporting the bridge on the eastern end are painted with huge murals as part of Chicano Park, the most extensive collection of Chicano art murals in the world.[21] This neighborhood park and mural display were created in response to a community uprising in 1970, which protested the adverse effects of the bridge and Interstate 5 on the Barrio Logan community. Local artist Salvador Torres proposed using the bridge and freeway pillars as a giant canvas for Chicano art at a time when urban wall murals were rare in the United States, and he and many other artists created the murals when permission for the park was finally granted in 1973.

Suicides

The Coronado Bridge is frequently used as a suicide bridge; as of July 2017, at least 407 suicide deaths by bridge jumpers have occurred on the Coronado, trailing only the Golden Gate Bridge in San Francisco as the bridge most-often used for suicide in the United States.[22] Solar-powered phones were once installed on the Skyway to offer direct help for those contemplating suicide, but have since been removed.[23] Signs have been placed on the bridge urging potential suicides to call a hotline. However, call boxes are not provided.[24]

After an accident in 2016, where a drunk driver drove a pickup truck off the bridge and into Chicano Park, killing 4 and injuring 9, state senator Ben Hueso proposed a state funding bill to cover safety measures on the Coronado and require reports to the state legislature on progress. In February 2017, Caltrans announced its intent to perform a feasibility study for suicide-dissuasion options for the bridge. Hueso stated, "The safety of residents and visitors traveling on the bridge, and those who gather below it in Chicano Park, is of the utmost importance."[25] On March 26, 2018, Caltrans released its report; it outlined suicide-dissuasion options such as netting, fencing, and glass barriers.

In 1972, three years after the bridge was opened to traffic, the first "suicide" was recorded. It was subsequently reclassified as a murder after an investigation determined that Jewell P. Hutchings, 52, of Cerritos had been forced to jump at gunpoint. Her husband, James Albert Hutchings, was subsequently charged with murder and pleaded guilty to involuntary manslaughter.[26]

Lighting

In April 1997, the Port released an international call for artists seeking qualifications of artist-led teams interested in developing environmentally-friendly lighting concept proposals for the bridge.[27] In 2010, a London-based design group led by Peter Fink was chosen.[28] The winning concept envisages illuminating the bridge with programmable LED lighting in an energy-neutral manner using electricity generated by wind turbines.[29] In 2012, two long years after choosing Fink's project, the Port finally cut a check for $75,000 to initiate fundraising in concert with the San Diego Foundation.[30] The Port of San Diego says no taxpayer dollars will be used. Instead, they are relying on grants and private donations to fund this lighting project, which will ideally be complete by 2019 to coincide with the bridge's 50th anniversary. As of March 2014, the working target date was 2019.Three of the bridge's columns were illuminated from November 8 to November 14, 2020, as part of a lighting field test.[31] [32] [33]

Urban legend

A decades-old local urban legend claims the center span of the bridge was engineered to float in the event of collapse, allowing Naval ships to push the debris and clear the bay. The myth may have developed due to the hollow box design of the 1,880-foot center span, combined with the low-profile barges that made it appear to float on its own during construction. However, Caltrans and the bridge's principal architect, Robert Mosher, maintain that the legend is false.[34]

External links

Notes and References

  1. News: EXCLUSIVE: Divers Inspect Coronado Bridge . Payton, Mari . Krueger, Paul . May 8, 2013 . NBC San Diego . February 17, 2015 .
  2. Book: https://books.google.com/books?id=fYcAAQAAQBAJ&pg=PA74 . Handbook of International Bridge Engineering . Chen, Wai-Fah . Duan, Lian . Kozy, Brian . Duan, Lian . 2.4: Steel Girder Bridges . 74 . CRC Press . 978-1-4398-1029-3 . Boca Raton . 2014 . February 17, 2015 .
  3. Web site: San Diego – Coronado Bridge Seismic Retrofit Project . March 1999 . . Caltrans . February 17, 2015 .
  4. Web site: San Diego-Coronado Bridge Fact Sheet . August 2009 . . Caltrans . February 17, 2015 .
  5. Web site: 2013 Named Freeways, Highways, Structures and Other Appurtenances In California . . January 2014 . Caltrans . February 17, 2015 . https://web.archive.org/web/20090117180606/http://www.dot.ca.gov/hq/tsip/hseb/products/Named_Freeways.pdf . January 17, 2009 . live .
  6. Book: Brandes, Ray. San Diego: An Illustrated History. Rosebud Books. Los Angeles. 1981. 150. 0-86558-006-5.
  7. Book: Linder, Bruce. San Diego's Navy. Annapolis, Maryland. Naval Institute Press. 2001. 156–157. 1-55750-531-4.
  8. Book: San Diego: California's Cornerstone. Engstrand, Iris. 186. Sunbelt Publications. 2005. 978-0-932653-72-7.
  9. Web site: Interim Technical Guidance (ITG) — Facilities Homeporting Criteria for Nimitz Class Aircraft Carriers . Bolton, P.N. . Naval Facilities Engineering Command (NAVFAC) . November 3, 1998 . Whole Building Design Guide . February 17, 2015 . 2-2. Entrances and Harbors – site specific criteria
      e. Vertical Bridge Clearances – 250 ft. Mean Higher High Water (MHHW) when ship is in light condition. Light condition occurs when ship has no aircraft, airwing, ammunition, and has 55% of JP-5, 10% of provisions and stores, 10% of potable water, aircraft handling vehicles, and 25% onboard discharge tank water. This height is based on the older CVs. If the facility is designed explicitly for Nimitz class, use 230 ft. MHHW. .
  10. Web site: 2021-01-16 . What Makes the Coronado Bridge Famous? . 2022-11-02 . 1906 Lodge Hotel Coronado Island Rated #1 on TripAdvisor . en.
  11. Web site: 24 January 2017 . Coronado Bridge: History, Construction & Facts . 2022-11-02 . study.com . en.
  12. Web site: San Diego–Coronado Bridge . Bermudez, Yader A. . February 26, 1999 . Caltrans . California Department of Transportation . April 23, 2011.
  13. Web site: Prize Bridge : 1970's Winners . . 2015 . National Steel Bridge Alliance . February 17, 2015 .
  14. Shibanpo Bridge Breaks World Record for Longest Box Girder Bridge Span . . Fall 2006 . Segments . 48 . American Segmental Bridge Institute . February 17, 2015 .
  15. Web site: Frequent Questions . Coronado Visitor Center . . December 18, 2009 . https://web.archive.org/web/20090519194833/http://www.coronadovisitorcenter.com/CVC/coronado-faq.html . May 19, 2009 . dead .
  16. Web site: Coronado Bridge Turns 40 . . August 3, 2009 . ABC 10News . February 17, 2015 .
  17. News: Panel to discuss return of Coronado bridge tolls . Zúñiga, Janine . February 19, 2009 . San Diego Union-Tribune . August 21, 2011 .
  18. News: Removal Of Coronado Bridge Toll Booths Proposed . ABC 10News . October 27, 2011 . September 10, 2015.
  19. Web site: About – Navy's 30th Bay Bridge Run/Walk. Navy's Bay Bridge Run/Walk. 2016-01-24. en-US.
  20. Web site: Bike the Bay . . Bike the Bay . 2015 . February 17, 2015 .
  21. News: A Turning Point: The Conception and Realization of Chicano Park . Delgado, Kevin . Journal of San Diego History . Winter 1998 . April 23, 2011.
  22. News: Coronado bridge suicide prevention prototypes unveiled, funding in question. Smith. Joshua Emerson. San Diego Union-Tribune. 2018-03-29. en-US.
  23. Through the Air into Darkness. Hagstrom, Suzy . October 12, 2000 . San Diego Reader.
  24. Web site: Coronado to Study Bridge Barrier. NBC 7 San Diego. 2016-01-24.
  25. News: New study looks at ways to stop suicides off Coronado bridge. Wilkens. John. San Diego Union-Tribune. 2018-03-29. en-US.
  26. News: San Diego Reader . September 21, 2012 . A Big Message . Hagstrom, Suzy . October 5, 2000 .
  27. Web site: San Diego-Coronado Bay Bridge Lighting Project (Background) . . Port of San Diego . July 13, 2014.
  28. News: Winning lighting design chosen for Coronado Bridge . . August 6, 2010 . February 17, 2015 . CBS8.
  29. Web site: Peter FINK, San Diego Coronado Bridge (USA) . Public Art directory . . February 17, 2015 .
  30. News: San Francisco stole our lights and our thunder . Jenkins, Logan . March 11, 2014 . February 17, 2015 . San Diego Union-Tribune .
  31. Web site: Coronado Bridge Lighting Project . Port of San Diego . PortOfSanDiego.org . 12 November 2021 . en.
  32. Web site: Holmes . Damian . The lighting of the Coronado Bridge, San Diego reaches large-scale testing phase . World Landscape Architecture . 23 December 2020 . 12 November 2021.
  33. Web site: Testing Underway for Coronado Bridge Lighting Art Project . NBC 7 San Diego . 12 November 2021.
  34. News: Kyle. Keegan. Fact Check: A Bomb Resistant, Floating Coronado Bridge? . Voice of San Diego . January 6, 2011. March 9, 2022.