April 20, 2007

 

GOLDEN GATE BRIDGE TO HONOR 70TH ANNIVERSARY

WITH RELEASE OF NEW BOOK
The Golden Gate Bridge, Report of the Chief Engineer,

Volume II

 

Monday, May 28, 2007, marks the 70th Anniversary of the Golden Gate Bridge (Bridge).

After 2 pm on Thursday, May 10, 2007, a new limited edition (1,000 copies only) collectible hardcover book, The Golden Gate Bridge, Report of the Chief Engineer, Volume II, May 2007, by Mr. Frank L. Stahl, P.E., Mr. Daniel E. Mohn, P.E., and Ms. Mary C. Currie will be available for the purchase price of $70 plus tax/shipping. The book will be available through Bridge Gift Center (on the southeast side) and through the on-line store at www.goldengate.org.

Volume II is the narrative of the many technical, political and financial challenges faced from the late 1940s through the turn of the twenty-first century. It chronicles the most crucial engineering and design challenges met since the Bridge opened. It is an accounting of growth of the Golden Gate Bridge, Highway and Transportation District from its singular responsibility of operating the Bridge for more than three decades to its added responsibility for providing regional public bus and ferry transit services in the Highway 101/Golden Gate Corridor starting in the early 1970s.

Also, by mid-May 2007, the 5th annual Golden Gate Bridge Collectible Holiday Ornament will debut at the Bridge Gift Center and on-line at www.goldengate.org.

 

Golden Gate Bridge Turns 70 Years Old

The Golden Gate Bridge (Bridge), San Francisco, CA, is widely recognized as one of the greatest construction achievements in the twentieth century. Once the longest suspension span ever built, the Bridge is considered an international icon, a structure of grace and beauty, and a lasting symbol of American progress and ingenuity.

The Bridge was constructed as a vital transportation link between the growing urban center of the City and County of San Francisco and the vast Redwood Empire to the north. Since opening, it has served as a critical link in California’s highway system and as an engine of economic vitality, supporting the San Francisco Bay Area’s commerce and tourism. In 1937, it could not have been imagined that this magnificent span, now one of the most recognized symbols in the world, would be visited by millions each year and crossed by 40 million vehicles annually. Since opening to traffic on May 28, 1937, more than 1,769,579,433 have crossed the span.

Initially, the idea of a bridge to span the Golden Gate Strait at the entrance to the San Francisco Bay was one that was met with extreme skepticism and dubbed “the bridge that couldn’t be built.” But the idea of a bridge prevailed, and in December 1928, California Legislature designated the Golden Gate Bridge and Highway District as the entity to design, construct, and finance the Bridge. The District was comprised of six-member counties: San Francisco, Marin, Sonoma, Napa and portions of Del Norte and Mendocino.

Overcoming seemingly insurmountable political, technical, and financial challenges, under the leadership of Chief Engineer Joseph B. Strauss, the now famed span opened to pedestrians on May 27, 1937, and to vehicular traffic on May 28, 1937, at twelve o’clock noon when President Franklin D. Roosevelt pressed a telegraph key in the White House to announce the event to the world. The Bridge, with a main span of 4,200 feet, remained the longest suspension span ever built until the Verrazano-Narrows Bridge in New York open in 1964 with a main span of 4,260 feet.

The 1.7 mile long bridge, under construction from January 1933 to April 1937, became a reality only because of the will of the people who went to the polls on November 4, 1930, and voted to back the $35 million bond issue to finance construction of the Bridge. On July 1, 1971, the original construction bonds were retired—$35 million in principal and nearly $39 million in interest all financed entirely from tolls.

The Bridge is commonly considered one of the most beautiful examples of bridge engineering. It is distinctive because of its striking design, its unique aesthetics that emphasize light and simplicity, rather than solidity and complexity along with its shapes and forms that heighten its tremendous scale and beauty. Its detailed Art Deco styling, International Orange color, extraordinary illumination, the arch over Historic Fort Point all set the Bridge apart from all other suspension spans of the era as both an architectural masterpiece and environmental sculpture.

With four funding sources available to fund operations—Bridge tolls, transit fares, government grants, and concessions and advertising— the structural integrity of the span is held as the highest priority. The Bridge stands today as a testament to its past and present Board members; managers and staff; elected officials; engineers; consultants; geologists; seismologists; planners; contractors; bridge workers; and the many, many hundreds of others who have contributed to making the Bridge the revered and beloved structure that it remains today.

Recognitions and Distinctions
Over the decades, the Golden Gate Bridge has earned numerous recognitions and distinctions. In 1980, the Bridge was determined to be eligible for listing in the National Register of Historic Places. The Bridge was also designated as California Historical Landmark No. 974. The American Society of Civil Engineers has honored the span three times by naming it as a Historic Civil Engineering Landmark in 1984, one of Seven Civil Engineering Wonders of the United States in 1997, and as one of the Civil Engineering Monuments of the Millennium in 2001.

In 1993, the Society of American Registered Architects’ gave it the Distinguished Building Award in recognition of enduring excellence in design. In 1999, the Bridge was designated as a San Francisco Landmark and it was ranked number two in the list of the Top 10 Construction Achievements of the 20th Century. In 2000, the Bridge was named the winner of the second annual Gustav Lindenthal Medal as the most significant engineering project of the twentieth century. The span has also been recognized twice by the U.S. Postal Service, with the release of two postcards featuring the Golden Gate Bridge on June 2, 1997, and the release of the ‘Turn of the Century’ series Golden Gate Bridge stamp, on September 3, 1998.

Key Preservation Projects
Since its completion in 1937, a number of major rehabilitation projects have been undertaken to preserve, protect and extend the life of the Bridge. The Bridge has been the scene of many “firsts,” with an unprecedented number of breakthrough projects occurring on a single structure. The culmination of these successes has set the stage for the Bridge to not only be recognized around the world as a magnificent engineering structure, but as a leading institution of innovation and achievement.

The Bridge structure itself played a leading role in the investigation of long span suspension bridge behavior, in the development of modern design theories, and in the application of modern bridge maintenance methods. Stellar examples of these include the first-ever total replacement of all 250 pairs of vertical suspender ropes completed in 1976; the successful replacement of the original concrete roadway deck with a lighter, stronger, orthotropic steel deck in 1986; and a comprehensive seismic retrofit of the entire span which is underway today with two of three construction phases now completed. Other notable projects include the 1954 addition of a lower lateral bracing system to increase the stability of the Bridge and the 1982 earthquake retrofit of the approaches to the Bridge.

Traffic Management Innovations
By the 1960s, with the public’s growing automobile obsession which resulted in a significant increase in traffic congestion, the Bridge became the setting of several significant traffic management innovations. On October 29, 1963, the use of reversible lanes to improve commute period traffic was inaugurated and on October 19, 1968, the world’s first one-way toll system. In the early 1970s, the Bridge ventured into then uncharted territory when it launched public bus and ferry transit system. On November 10, 1969, California Legislature expanded the District’s authority allowing the development of a mass transportation system in the Golden Gate Highway U.S. 101 Corridor. It was then that the agency name was changed from the Golden Gate Bridge and Highway District to the Golden Gate Bridge, Highway and Transportation District. The most recent advancement in the improvement of traffic flow across the span was the July 2000 launch of the FasTrak® electronic toll collection system—now with 70% of commuters using the system.

Bridge Stats
Total length including approaches: 1.7 miles or 8,981 feet
Length of main span of suspended structure (distance between main towers): 4,200 feet
Width: 90 feet
Width roadway between curbs: 62 feet
Clearance above mean higher high water: 220 feet
Total weight including anchorages and approaches: 887,000 tons
Maximum transverse deflection at center span: 27.7 feet
Maximum downward deflection at center span: 10.8 feet
Maximum upward deflection at center span: 5.8 feet

Height of main towers above water: 746 feet
Height of main tower above roadway: 500 feet
Weight of one main tower: 22,000 tons

Diameter of one main cable with wrapping: 36 and 3/8 inches
Length of one main cable: 7,650 feet
Total length of wire used in both main cables: 80,000 miles
Number of galvanized wires in one main cable: 27,572