Golden Gate Bridge

The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. As part of both U.S. Route 101 and California State Route 1, it connects the city of San Francisco on the northern tip of the San Francisco Peninsula to Marin County. The Golden Gate Bridge was the longest suspension bridge span in the world when it was completed during the year 1937, and has become an internationally recognized symbol of San Francisco and California. Since its completion, the span length has been surpassed by eight other bridges. It still has the second longest suspension bridge main span in the United States, after the Verrazano-Narrows Bridge in New York City. In 1999, it was ranked fifth on the List of Americas Favorite Architecture by the American Institute of Architects.

Strauss was chief engineer in charge of overall design and construction of the bridge project. However, because he had slight experience with cable suspension designs, responsibility for much of the engineering and architecture fell on other experts. Irving Morrow, a relatively unknown residential architect, designed the overall shape of the bridge towers, the lighting scheme, and Art Deco elements such as the streetlights, railing, and walkways. Senior engineer Charles Alton Ellis, collaborating remotely with famed bridge designer Leon Moisseiff, was the principal engineer of the project. Moisseiff produced the basic structural design, introducing his deflection theory by which a thin, flexible roadway would flex in the wind, greatly reducing stress by transmitting forces via suspension cables to the bridge towers.

The bridge-opening celebration began on May 27, 1937 and lasted for one week. The day before vehicle traffic was allowed, 200,000 people crossed by foot and roller skate. On opening day, Mayor Angelo Rossi and other officials rode the ferry to Marin, then crossed the bridge in a motorcade past three ceremonial "barriers," the last a blockade of beauty queens who required Joseph Strauss to present the bridge to the Highway District before allowing him to pass.

The center span was the longest among suspension bridges until 1964.The Golden Gate Bridge also had the world's tallest suspension towers at the time of construction and retained that record until more recently. The weight of the roadway is hung from two cables that pass through the two main towers and are fixed in concrete at each end. Each cable is made of 27,572 strands of wire. There are 80,000 miles or 129,000 km of wire in the main cables. The bridge has approximately 1,200,000 total rivets.

The color of the bridge is officially an orange vermillion called international orange. The color was selected by consulting architect Irving Morrow because it compliments the natural surroundings and enhances the bridge's visibility in fog. The bridge is said to be one of the most beautiful examples of bridge engineering, both as a structural design challenge and for its aesthetic appeal. It was declared one of the modern Wonders of the World by the American Society of Civil Engineers. It is the most beautiful and most photographed bridge in the world.

Aesthetics was the foremost reason why the first design of Joseph Strauss was rejected. Upon resubmission of his bridge construction plan, he added details, such as lighting, to outline the bridges cables and towers. The bridge was originally painted with red lead primer and a lead based topcoat which was touched up as required. In the mid 1960s, a program was started to improve corrosion protection by stripping the original paint and repainting the bridge with zinc silicate primer and vinyl topcoats. Since 1990 Acrylic topcoats have been used instead for air-quality reasons. The program was completed in 1995 and it is now maintained by 38 painters who touch up the paintwork where it becomes seriously eroded.