INTRODUCTION TO IMMERSED TUBE TUNNELING SYMPOSIUM. IN: PREPARING FOR CONSTRUCTION IN THE 21ST CENTURY, PROCEEDINGS OF CONSTRUCTION CONGRESS '91, SPONSORED BY THE AMERICAN SOCIETY OF CIVIL ENGINEERS IN COOPERATION WITH THE AMERICAN INSTITUTE OF MINING ENGINEERS AND THE AMERICAN ARBITRATION ASSOCIATION, CAMBRIDGE, MASSACHUSETTS, APRIL 13-16, 1991

The papers in this section of the conference focus on the design and construction of immersed tube tunnels for Boston's Central Artery Project. The Third Harbor Tunnel will be a steel shell tube immersed tube tunnel located under Boston Harbor between East and South Boston. The Fort Point Channel will be a concrete tube tunnel. Lastly, the authors discuss innovative possibilities for future immersed tube tunnels. Innovations inclue tethered floating tubes. These techniques will not only result in the possibility of constructing tunnels in extremely deep water, but will also minimize the disposal of excavated materials which, as discussed above, has been a major issue in recent immersed tube tunnels.