Screw Pilings

[MTChE]

I am the on-site engineer for a process plant project. The soils on the site vary wildly from 500 psf to 4000 psf depending on location. Our contractor building the facility will use screw pilings for supports for pipe racks and cable trays. The screws will be put in soil that is mildly erodable (Kw 0.28 to Kw 0.37) and mildly corrosive (pH 8.3 to 8.7). We have told the prospective screw piling vendors to make recommendations for dealing with the corrosion issue and one suggested galvanized pilings. Would this be a good option?

 

[rscassar]

I had a piling contractor design the screw piles to take into account corrosion of the cross section. They considered 2.0 mm of the pile wall thickness to be sacrificial and did not include this 'sacrificial steel' in their calculations.

 

[six06]

by screw piles you mean Helical piles?

 

[csd72]

Galvanising is not a fix all for everything, I suggest you do some reading:

http://www.galvanizeit.org/

 

[rscassar]

It can be done, I just noticed when reading through specifications for screw piles:

Once manufactured screwpiles are to be visually inspected and approved prior to hot dip galvanising if required.

CORROSION PROTECTION TO SCREWPILES
1. Steel screwpiles to be designed in accordance with [clause from local code] with an allowance for sectional loss based on the site corrosion classification and design life.