Walter J. Papp, Jr. (center) presented Golden Apples to Mr. Fisher (left) and Mr. Rhyner (right) after the Kapp Lecture (Photo by Robert Talby)

Amtrak's Thames River Bridge in Connecticut spans from New London to Groton and was originally constructed in 1918. During a recent major construction work to convert the original bascule to a new lift structure, one end of a caisson dating from 1918 abruptly settled 1.5 inches during installation of adjacent piles. The abrupt settlement and continuing creep interfered with operation of the moveable span, which stayed in service during construction. After an intense study of options, an unusually deep grouting program was begun that lasted ten months and ultimately placed more than one million gallons of grout to stabilize the bridge.

Alan Fisher represented the contractor on this job, Cianbro, and started the talk by providing a historical background about the construction of this bridge, accompanied by drawings and photographs of the bridge's original design and construction. He related how the problem came to be noticed and the causes identified.

Fred Rhyner of Mueser Rutledge was involved originally as a reviewer on the project and stepped in to design a ground improvement program to stop the settlement. He described the site characterization program, which was utilized to prepare an elaborate grouting scheme, and was eventually successful in arresting the settlement and brought the bridge span to a stable configuration, where the lift span could be safely installed.

Summary by Anirban De