The History of Helical Piers

The Helical Pier was invented by a blind Irish brickmaker, named Alexander Mitchell in 1833. The very first Helical Piers were made of cast iron and were used to build lighthouses exposed to raging seas and heavy ice fields. The Helical Pier shafts were from 3 to 8 inches in diameter with the helices ranging from 18” to 60” in diameter! The Helical Piers were torqued down to 10 to 20 feet into the soil by 30 to 40 men, pushing 6 to 8 capstan bars. The first such structure was built on Maplin Sound at the mouth of the Thames River in 1838. In the United States, the first Helical Pier tower was built at in 1843 at the Black Rock Harbor in Connecticut. Capt. William D. Swift of the Army Corps of Topographical Engineers was the architect. Prior to construction he traveled to England to study the Maplin Sands Lighthouse and talk with Alexander Mitchell

Another early lighthouse constructed on Helical Piers in the United States was erected in the Delaware Bay, New Jersey, on Brandywine Shoal.

The Brandwine Shoal made a precarious site for a lighthouse structure. The first tower had been constructed in 1828, but was demolished by storms and replaced by lightship. It wasn’t until 1850 that a second tower was attempted.

Marine engineers, Maj. Hartman Bache and Lt. George G. Meade, were both young and energetic when they were appointed by Congress to design and build Brandywine Shoal Lighthouse, eight miles offshore. Alexander Mitchell sailed to Delaware to serve as a consultant on the project. The 46-foot lighthouse has 32 screw piles supporting a keeper’s house and was fortified by tons of riprap dumped around its base to prevent ice floes from shearing off its legs. The pricetag was $53,317.

At the time, this was regarded as “breakthrough technology”. Despite harsh weather, the Delaware Bay tower served for more than 60 years! Since then Helical Piers are becoming the preferred choice of deep foundation systems for a growing number of applications.