Dry Tortugas National Park
Accessible only by boat or seaplane, the remote Dry Tortugas National Park is a former military fort and prison 70 miles West of Key West built during the Civil War. Known as the home of magnificent Fort Jefferson, it is surrounded by water, vibrant coral reefs and protected marine/bird life. Any new construction had to deal with the limitations of a seven-foot-wide bridge with limited weight capacity and restricted headroom.
Limited access to the fort was the main reason helicals were used. A seven-foot-wide bridge presented both width and weight capacity challenges. In addition, there were site headroom restrictions. A traditional auger rig (required for a concrete solution) could not have been used due to its size, vibration, noise disruption, weight, and mobilization requirements. CHANCE® Helical Piers were an ideal solution.