The Alvord Lake Bridge was the first reinforced concrete bridge built in the United States, and to this day remains a viable entrance into San Francisco's Golden Gate Park as the oldest standing bridge on the grounds.
Built in 1889 and designed by Ernest Leslie Ransome, the bridge is constructed of a single arch that measures 64 feet wide and 20 feet long. Ransome is often recognized as an innovator of reinforced concrete, a method that adds steel reinforcing bars to the concrete to improve its strength, and is responsible for other notable structures in San Francisco.
Alvord Bridge and the nearby "lakelet" of a slightly earlier installation were named for William Alvord, who was the park commission president and later held court as mayor of San Francisco.
A few years after completing the Alvord Lake Bridge, Ransome left the city because of its "blatant disregard" for concrete construction. Ironically, just a few years later, the Alvord Lake Bridge, along with other reinforced concrete structures, made it through the 1906 earthquake unscathed. Experts theorize that if concrete construction had been more prevalent throughout the city at that time, the overall earthquake damage would have been less severe.
Today, the bridge serves as a remarkable example of modern day construction, and is even recognized by the American Society of Engineers as a civil engineering landmark. Aside from the damage to the whimsical concrete stalactites on the underside of the arch, the bridge has remained in pristine condition, just as Earnest Ransome had planned.