Case Study: The Cape Hatteras Light Station Relocation Project
The nation's tallest brick lighthouse at about 208 feet, the Cape Hatteras Light Station had been deluged with ocean waves for decades and coastal erosion was threatening the structure. Through the years, many different efforts, such as the building of barrier walls in the 1930's and the use of sandbags through the 1980's, had been used in vain attempts to hold back the sea and to mitigate the effects of shoreline erosion. By 1987, the lighthouse, which had been situated 1,600 feet from the shore when it was activated in 1870, was only 120 feet from the ocean.
Though its significance related to coastal navigation has diminished, the Cape Hatteras Light Station has been designated a National Historic Civil Engineering Landmark and has been placed on the National Register of Historic Places. The federal government decided in 1989 that the most cost-effective and environmentally sensitive way to preserve the lighthouse, including two keeper's quarters and three water cisterns, was to move it a half-mile inland, again placing it 1,600 feet from the shore. The National Park Service was provided $9.8 million to move the lighthouse complex.
The move process started with removing more than 800 tons of the granite base of the lighthouse and installing steel support towers equipped with hydraulic jacks. The lighthouse was then lifted up six feet and steel support beams installed to form a temporary foundation. One hundred hydraulic jacks acting on rollers that slid along track beams allowed the lighthouse to move easily and be kept level.
Workers compacted the natural sands, placed crushed stone and then steel mats to form a roadway over which the lighthouse was moved. To make the half-mile journey inland to its new home, workers used five hydraulic push jacks to slowly nudge the lighthouse along the track beams in five-foot increments. Once over the new concrete mat foundation, the lighthouse was lowered to the correct level, and the temporary steel foundation was replaced with a structural brick infill.
Viewed by more the 20,000 visitors daily, the lighthouse began its journey on June 17, 1999, and arrived at its destination on July 9, 1999, about three weeks ahead of schedule. Once again 1,600 feet from the shoreline, the lighthouse reopened to the public on Friday, May 26, 2000.
Additional information available at: http://www.nps.gov/archive/caha/lrp.htm