Since the 1930s, numerous efforts were made to protect the lighthouse from the encroaching sea. The Coast Guard installed walls perpendicular to the shore to protect the tower. By 1936 these proved to be ineffective - the lighthouse was abandoned to the sea and its original light moved to a skeleton steel tower. A severe storm in 1980 accentuated the island's westward movement and caused the National Park Service (NPS) to begin planning, under the National Environmental Policy Act, for long-term protection. In 1987, the NPS requested the assistance of the National Academy of Sciences, a group of scientists and engineers who advise the federal government on technical matters. The Academy's 1988 report, Saving Cape Hatteras Lighthouse from the Sea: Options and Policy Implications, considered ten options but recommended relocation as the most cost-effective method of protection. But how to move a 120-year old landmark without inviting disaster? Critics said it could not be done. Enter the engineers.
To accomplish this feat, the original foundation down to the pine timbers was replaced by temporary shoring beams and supports. Hydraulic jacks built into the main beams were used to raise the tower approximately 6 feet so roll beams and rollers could be introduced. After all jacks were shored, the system was pressurized and the jacks began lifting. At this point it was ready to roll. After it was lifted, the tower moved along to its new location 2,900 feet to the southwest on steel mats starting on June 17, 1999. Steel track beams became rails and roller dollies permitted the support frame to move along the track. The lighthouse was equipped with sixty automated sensors to measure the transfer of the load, tilt, vibration, and shaft diameter. A weather station was installed at the top to monitor wind speed and temperature.
The Principal Keeper's Quarters, Double Keepers’ Quarters, oil house, cisterns, and sidewalks, were moved before the lighthouse in February, March, and April. On July 9, 1999 the lighthouse was carefully placed onto its new foundation, which consisted of a 60' x 60' steel-reinforced concrete slab 4 feet deep, 5 feet of brick, and 1 1/2 to 2 feet of rock. The light station was whole once again with all the buildings being in the same relative position as they were originally. The Cape Hatteras Lighthouse resumed its duties on November 13, 1999 and continues to do so to this day. Now safely 1,600 feet from the ocean, it should not be threatened by the indomitable ocean waves for another 100 years.
I hope you will join me over the next few articles as we delve deeper in the field of engineering. I will be exploring past and present engineering projects and their impact on society as well as the ever-expanding need for engineers. Designers imagine the future – engineers build it.
By
Alan Cundiff
Alan is a freelance writer for Engineer-Jobs.com. He has more that 30 years work experience in the environmental engineering and government regulatory fields. To read more of his blogs, please go to Engineer-Jobsblog.com, and be sure to check out the postings for jobs in nearly any industry at Nexxt .
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