Recent Advances in Prefabricated Vertical Drains

Modern port development on the US East Coast and Gulf Coast many times takes place on soft and compressible sites. As such, ground improvement is employed to meet project design criteria. Due to the relative economy of implementing surcharge combined with prefabricated vertical drains, the use of prefabricated vertical drains is growing. To meet the demands of deeper installations, more difficult site conditions, and stricter quality control, the prefabricated vertical drain industry has evolved significantly over the past 5 years. To highlight industry advancements, three case histories for prefabricated vertical drains are presented including the Virginia Port Authority and the U.S. Army Corps of Engineers project - Craney Island Eastward Expansion; the South Carolina State Ports Authority project - Charleston Naval Base Container Terminal; and the Mississippi State Port Authority at Gulfport - West Pier project. The three case histories are presented together to compare and contrast project design criteria, project specifications, and construction quality control. Unique aspects of each project are discussed, as well as industry advancements implemented on each project. Each project individually required installation of 1.8 to 4.8 million meters of prefabricated vertical drain. The paper presents construction considerations and the potential for the expanded role of prefabricated vertical drains in port development.