In the early 1800’s, the very first recorded design and use of helical foundations took place in England to support lighthouses in tidal basins. Today, helical piles offer numerous economic solutions to support structural foundations. As one of the leaders in the helical pile and products market, MacLean Civil Products Group (MCP) offers proven and high quality helical piles that have been evaluated by the AC358 helical pile acceptance criteria as documented in the (ICC-ES) ESR-3032 report. Additionally, MCP offers our patented (US 8,777,520 B2) square-on-square coupler system, which increases pile performance and reduces installation time. To create a cost-effective grouted helical pipe pile, the installer can easily connect our MCP cutter plates to our square-on-square connection.
Working with one of our United States distributors, MCP supplied over a thousand piles to a customer site in the northeast. Our customer’s site plans called for a multistory structure to be placed on low consistency soils that encounter tidal influence. Foundation plans called for P35H, or 3.5″ O.D. (0.300″ wall thickness) helical piles with 10″, 12″, 14″ helix configuration followed by a P35H extension with two 14″ helices and P35H extensions in conjunction with an 8″ diameter grout column in the upper 18 feet of the pile assembly. The supplied piles have a maximum torsional capacity of 15,000 ft.-lbs. and ultimate load capacity of 105,000 lbs. with a Kt factor of 7. The 8″ grout column assisted in stabilizing the piles laterally while increasing the compression capacity.
Over one thousand piles were installed to complete the foundation pile work. Soil testing indicated that this site was susceptible to increased corrosion due to the high resistivity values found in the soil combined with Jamaica Bay’s tidal action. Helical piles are often protected with a hot-dip galvanized zinc coating in aggressive soils to achieve the needed service life. In isolated cases, further corrosion protection is needed. Due to soil conditions for this project, cathodic protection was used to protect the steel by minimizing the rate of corrosion with a sacrificial anode. This solution offered cost-effective corrosion protection prolonging the service life of the helical piles.
The MCP anchor team is always striving to build solid foundations worldwide in various projects of diverse nature.
Aerial views of project site along shoreline. Bottom right shows wires connecting the pile caps to the anode for cathodic protection.