Lecture No. 2: Amtrak
Peter Finch, project director from Amtrak gave a great technical presentation on the work done for the replacement of the vertical lift span of the Thames River Bridge located in Groton and New London, CT. This bridge has a lot of traffic with about 38 trains per day and over 1600 annual openings, including opening for the United States Navy and Coastguard.
Some of the major design elements for this project were replacing the bascule, modifying the channel piers and constructing two 135 foot lift towers for a span of 188 feet, while retaining the approach spans and finding an efficient way to remove the old counterweights.
A major problem faced during this project was the settling of one of the piers after construction. This became most important when the settlement did not appear to be stopping. The settlement caused sinking and tilting of the pier which prohibited the opening of the bridge. This problem was eventually solved through permeation grouting which filled the voids that had been causing settlement underneath the pier.
Though there were unforeseen challenges in the replacement of this lift span, the problems were solved effectively. With a goal of July 4th, the bridge was complete for limited scheduled openings by July 1st and the approach spans are ready for painting in the near future.