Engineers

Corrosion - General

The issue of corrosion of steel in ground has long been debated in numerous publications and forums.

Corrosion relating to screwpile design often requires consideration from two environmental issues:

  1. Corrosion of steel in ground.
  2. Corrosion of steel in ambient conditions.

The pile head of a screwpile is either interfaced into a concrete "pilecap" or connected directly to steel or timber beams by way of interfacing brackets or direct welding.  These factors need to form part of the overall design consideration.

Corrosion assessment and calculation may include one or more of the following design options based on the intended structures required design life minimums:

  • Design allows for allowable sacrificial steel loss based available environmental & geotechnical information.
  • Design allows for upgradable steel sectional loss.
  • Design allows for protective coatings such as:
    • Hot dip galvanising
    • Two pac urathane coatings
    • Cathodic Protection

Below is a design comparison between a galvanised section v's a heavier wall section.  A cost analysis between the the two options shows the heavier wall black product option to be more cost effective however this is not always the case in all load case senarios.