Proceedings - 13th International Workshop on Micropiles - 2017, Vancouver, BC, Canada, (ISM, DFI, ADSC)
SUPPORT OF THE MORRIS ISLAND LIGHTHOUSE USING MICROPILES
William L. Snow, Sr., William B. Wright, PE, & Will Snow, Jr., PE
The current lighthouse structure was originally built approximately 1200 feet from the shoreline of the Atlantic Ocean. Over the years the Corp of Engineers have undertaken several programs to aid navigation and to keep the Charleston harbor open to increased shipping demands. Significantly, around the turn of the last century a pair of Jetties were constructed, drastically changing the approach direction for ships entering the Charleston harbor. In subsequent years the harbor began to experience accelerated siltation. In an effort to prompt a natural flushing mechanism for the harbor, an opening of several hundred yards across was accomplished near the shore intersection with the South Jetty. This breach, known locally as “Dynamite Hole” partially met its intended purpose, however the new flow of water began to rapidly scour the ocean face of Morris Island, located directly South of the “hole”. Within a few short years, the beach of Morris Island was eroded to such an extent that the MIL now sits surrounded by the sea. The original lighthouse was designed so that the wooden piles would always be below the existing water table of Morris Island. The theory being that the piles would not rot or deteriorate as long as they were continually submerged. The scouring of the soil importantly, to water born parasites such as ship worms or tereda worms, as they are locally known. The introduction of these organisms led to severe deterioration of the original support piles. The deterioration of the lighthouse structure and foundation led to the current effort to save the lighthouse from the harsh Atlantic environment. An organization known as “Save the Light” bought the structure in 1999, and is spearheading the effort to “Save the Light”.
|article #2647; publication #1033 (ISM- 2017)|