Open Well Caissons Of A 1917 Railroad Bridge: How 19th Century Construction Can Influence 21st Century Construction (f1b0a5f2-b1b8-41d4-bbfb-fab6f395e7a0)

Amtrak made a decision to replace an aging bascule bridge with a vertical lift bridge for their crossing of the Thames River in New London, Connecticut. The new lift bridge occupies the same alignment and shares the same foundations as the bascule span. During construction the deep foundation caisson supporting the bascule span settled and tilted. Investigation into possible reasons revealed interesting historical facts, both of the construction of the innovative open well caisson foundations and of the state-of-the-art in tremie concrete placing methods in use at the turn of the century. This paper describes both of these topics.