Sundial Bridge at Turtle Bay

The Sundial Bridge provides pedestrian access to the north and south areas of Turtle Bay Exploration Park, a complex containing environmental, art and history museums and the McConnell Arboretum and Gardens. It also forms the gateway to the Sacramento River Trail, a {{Convert|35|mi|km|adj=mid|-long}} trail completed in 2010 that extends along both sides of the river and connects the bridge to the Shasta Dam.{{citation |last=Ottesen |first=Peter |title=Finished trail is 35 miles of pure heaven |date=June 2, 2010 |url=http://www.recordnet.com/apps/pbcs.dll/article?AID=/20100602/A_SPORTS03/6020326 |archive-url=https://web.archive.org/web/20100614091802/http://www.recordnet.com/apps/pbcs.dll/article?AID=/20100602/A_SPORTS03/6020326 |archive-date=June 14, 2010 |url-status=dead |publisher=Recordnet}}. Drift boats of fishermen are often seen passing beneath the bridge as they fish for salmon, steelhead and rainbow trout.{{citation|title=Tourists lured by Redding bridge|journal=Sacramento Bee|date=October 5, 2005}}. In the distance, Mount Shasta is barely visible. Shasta Bally is visible to the West looking upstream the Sacramento.

File:Sundial Bridge (8843646383).jpg

File:Sundial Bridge time marker noon.jpg

The support tower of the bridge forms a single {{Convert|217|ft|m|adj=on}} mast that points due north at a cantilevered angle (42 degrees), allowing it to serve as the gnomon of a sundial. The spar's angle is slightly incorrect for it to be accurate the whole year, as the bridge's latitude is approximately 40.59 degrees. It has been billed as the world's largest sundial,{{citation|title=Redding is seeking to bridge image gap|journal=Sacramento Bee|date=July 12, 2001}}.{{citation |last=Fullwood |first=Janet |title=California's Seven Wonders: There's no shortage of the spectacular |date=July 26, 2007 |journal=Pittsburgh Post-Gazette |url=http://www.post-gazette.com/pg/07207/803169-37.stm}}.[https://www.post-gazette.com/life/travel/2007/07/20/California-s-Seven-Wonders-There-s-no-shortage-of-the-spectacular/stories/200707200299] although Taipei 101 and the associated sundial design of its adjoining park are much larger. The Sundial Bridge gnomon's shadow is cast upon a large dial to the north of the bridge. The shadow cast by the tower is said by the nearby time markings (see photo) to be exactly accurate on only one day in a year – the summer solstice, June 20 or 21 – but that has not been demonstrated. The time is given as Pacific Daylight Time. The tip of the shadow moves at approximately one foot per minute so that the Earth's rotation about its axis can be seen with the naked eye.{{Citation | title = Physics: For scientists and engineers with modern physics | last1 = Serway | first1 = Raymond A. | last2 = Jewett | edition = 7th | publisher = Thomson, Brooks/Cole | year = 2007 | isbn = 978-0-03-004538-7 }}. Back cover.

File:SundialBridgeCA2.jpg

File:Sundial Bridge.jpg

The Sundial Bridge is a cantilever spar cable-stayed bridge, similar to Calatrava's earlier design of the Puente del Alamillo in Seville, Spain (1992). This type of bridge does not balance the forces by using a symmetrical arrangement of cable forces on each side of its support tower; instead, it uses a cantilever tower, set at a 42-degree angle{{citation |title=Calatrava's "Sundial Bridge" Opens In Redding, California |date=July 21, 2004 |journal=Architectural Record |url=http://archrecord.construction.com/news/daily/archives/040721calatrava.asp |archive-url=https://web.archive.org/web/20040818192018/http://archrecord.construction.com/news/daily/archives/040721calatrava.asp |archive-date=August 18, 2004 |url-status=dead}}. and loaded by cable stays on only one side. This design requires that the spar resist bending and torsional forces and that its foundation resists overturning. While this leads to a less structurally efficient structure, the architectural statement is dramatic. The bridge is {{Convert|700|ft}} in length and crosses the river without touching the water, a design criterion that helps protect the salmon spawning grounds beneath the bridge.Santiago Calatrava's Sundial Bridge: Angle of Inspiration, Mill Valley Film Group, 2004. The cable stays are not centered on the walkway but instead divide the bridge into a major and minor path.

The cable for the bridge totals {{Convert|4,342|ft}} and was made in England. The dial of the sundial and a small plaza beneath the support tower are decorated with broken white tile from Spain. The bridge's deck is surfaced with translucent structural glass from Quebec, which is illuminated from beneath and glows aquamarine at night. The steel support structure of the bridge was made in Vancouver, Washington and transported in {{Convert|40|ft|m|adj=on}} sections by truck to Redding.

File:Sundialbridge2.jpg

Plans for the Sundial Bridge began in the 1990s, when the city of Redding budgeted $3 million for a pedestrian bridge across the river. However, costs escalated after Calatrava's design was chosen in 1996,{{citation|title=Walking Bridge That Soars: Backers See Stardom for Sundial Bridge|url=http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2004/06/30/BAGEN7EAIH1.DTL|journal=San Francisco Chronicle|date=June 30, 2004|first=Greg|last=Lucas}}. and the project supported by a small group of doctors, lawyers, and other professionals and opposed by other residents who thought it would be too expensive{{citation |last=Calvan |first=Bobby Caina |title=Bridge unites parkland, divides town: Some see path to future, others a misguided mess |date=April 5, 2004 |journal=Boston Globe |url=http://www.boston.com/news/nation/articles/2004/04/05/bridge_unites_parkland_divides_town/ |archive-url=https://web.archive.org/web/20040407044602/http://www.boston.com/news/nation/articles/2004/04/05/bridge_unites_parkland_divides_town/ |archive-date=April 7, 2004 |url-status=dead}}.{{citation|title=Coronary: A True Story of Medicine Gone Awry|first=Stephen|last=Klaidman|publisher=Simon and Schuster|year=2007|isbn=978-0-7432-6754-0|pages=[https://archive.org/details/coronarytruestor00klai/page/25 25–26]|url-access=registration|url=https://archive.org/details/coronarytruestor00klai/page/25}}. and who favored a more "folksy" covered bridge design.{{citation|title=Bridge Out of Nowhere Leads a Town to Its Future|journal=New York Times|url=https://www.nytimes.com/2004/02/19/garden/bridge-out-of-nowhere-leads-a-town-to-its-future.html|date=February 19, 2004|first=Patricia Leigh|last=Brown}}. The bridge was completed in 2004, three years later than originally planned, at a cost of $23.5 million, with funding from the Redding-based McConnell Foundation.{{citation|title=California's Timeless Bridge|journal=Washington Post|date=July 25, 2004|url=https://www.washingtonpost.com/wp-dyn/articles/A9484-2004Jul23.html|first=Christine|last=Vovakes}}.{{citation|title=Aesthetics and economy in pedestrian bridge design|last1=Woodruff|first1=Shawn|last2=Billington|first2=David P.|journal=International Journal of Space Structures|volume=22|issue=1|year=2007|pages=81–89|doi=10.1260/026635107781037310|s2cid=110630511}}. The expense was justified on the basis that it would increase tourism in the Redding area, which also features Shasta Dam as another architectural marvel, and it has been successful in that goal.{{citation|title=Redding's magnetic bridge; The Sundial span has a powerful pull. The architect's stunning creation has drawn tourists and is changing the city's image|journal=Los Angeles Times|date=June 3, 2007|first=Beverly|last=Beyette}}.

In the fiscal year following its grand opening, Turtle Bay Exploration Park, adjacent to the bridge, saw a 42-percent increase in its visitation. As of 2011, Redding's city manager stated that the bridge "continues to generate millions of dollars worth of commerce and tourism each year".{{citation|title=It's meant to startle – and it does|journal=Sacramento Bee|date=April 11, 2011|first=Loretta|last=Kalb|url=http://www.sacbee.com/2011/04/11/3543095/its-meant-to-startle-and-it-does.html|url-status=dead|archive-url=https://web.archive.org/web/20110430025132/http://www.sacbee.com/2011/04/11/3543095/its-meant-to-startle-and-it-does.html|archive-date=April 30, 2011}}.

In 2009, Nor-Cal Think Pink, a non-profit organization dedicated to raising awareness of the importance of early detection of breast cancer, received approval from the City of Redding to illuminate the Sundial Bridge in pink for its Think Pink Day. The event now takes place annually.[https://web.archive.org/web/20120425071428/http://www.norcalthinkpink.org/pink-sundial-bridge.php Nor-Cal Think Pink][http://www.redding.com/news/2009/oct/15/sundial-bridge-will-turn-pink-tonight-think-pink-b/ "Sundial Bridge turns pink for Think Pink Breast Cancer Awareness Day"] Redding.com[http://www.redding.com/news/2010/oct/18/txy-xy-xy-xyx-y-x/ "3 nights of pink lights"] Redding.com

The bridge is the cover image of a general physics textbook by Serway and Jewett, demonstrating the bridge resisting forces of wind and gravity.

• Puente de la Mujer, Buenos Aires, Argentina
• Samuel Beckett Bridge, Dublin, Ireland
• Puente de la Unidad, Monterrey, Mexico
• Alamillo Bridge, Seville, Spain

{{Reflist|2}}

{{Commons category}}

• {{official site|https://www.turtlebay.org/sundial-bridge}}
• [https://web.archive.org/web/20140531051535/http://www.turtlebay.org/sundialbridge Sundial Bridge official site] (archived)
• {{Structurae|id=20002419|title=Turtle Bay Sundial Bridge}}

Category:Bridges completed in 2004

Category:Bridges over the Sacramento River

Category:Cable-stayed bridges in the United States

Category:Pedestrian bridges in California

Category:Bridges by Santiago Calatrava

Category:Sundials

Category:Towers in California

Category:Redding, California

Category:Transportation buildings and structures in Shasta County, California

Category:Neo-futurist architecture

Category:Steel bridges in the United States

Category:Cantilever bridges in the United States

Category:Inclined towers

Category:Buildings and structures in Redding, California

Category:2004 establishments in California