Locale San Francisco Longest span 20ft Opened 1889 Width 20 m Architect Ernest L. Ransome | Official name Alvord Lake Bridge No. of spans 1 Total length 8.8 m Material Reinforced concrete | |
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Crosses Pedestrian entrance to San Francisco's Golden Gate park Heritage status American Society of Civil Engineers civil engineering landmark Bridge type Concrete bridge, Deck arch bridge Similar Ingalls Building, Sharon Meadow, San Francisco City Hall, Panhandle, San Francisco–Oakland Bay Bridge | ||
The Alvord Lake Bridge was the first reinforced concrete bridge built in America. It was built in 1889 by Ernest L. Ransome, an innovator in reinforced concrete design, mixing equipment, and construction systems. The bridge was constructed as a single arch 64 feet (20 m) wide with a 20-foot (6.1 m) span . Ransome is believed to have used his patented cold-twisted square steel bar for reinforcement, placed longitudinally in the arch and curved in the same arc. The face of the bridge was scored and hammered to resemble sandstone, the interior features concrete "stalactites" (some of which have subsequently grown due to redeposition of limestone from the concrete).
E.L. Ransome left San Francisco a few years later, frustrated and bitter at the building community's indifference to concrete construction. Ironically, the city's few reinforced concrete structures, including the Alvord Lake Bridge, survived the 1906 earthquake and fire in remarkable shape, vindicating Ransome's faith in the method.
The Alvord Lake Bridge, which arches over a pedestrian entrance to San Francisco's Golden Gate park, was designated a civil engineering landmark by the American Society of Civil Engineers in 1969.
Alvord lake bridge
