To visit past Bridges of the month, click on the above links.

    The Third Street Bridge in San Francisco, California, is also known as the Francis "Lefty" O'Doul Bridge after the native son  baseball player.  It is a trunnion bascule bridge built in 1933 crossing Mission Creek in the China Basin area of the city.  The engineer, Joseph Baerman Strauss (1870-1938), was known for his bascule bridges and was also the engineer behind the Golden Gate Bridge. A  bascule (from the French for "balance" or "see saw") movable) bridge works by having the large counterweights descend and raise the deck portion of the bridge.  The trunnion is the pivot point around which the bridge rotates.  Compare this with the Mystic, Connecticut Bridge also on this website.  The Virtual Museum of San Francisco has further information about Strauss and his work on other San Francisco bridges.