Nothing has Harmed the Driven Steel Pile more than Resistivity-PPT Presentation

PPT Presentation

Pdf Summary

The presentation argues that resistivity has been overused in assessing driven steel-pile corrosion. Resistivity measures how dissolved salts affect water’s electrical resistance; it is an indicator of possible corrosivity, not a direct cause or reliable predictor of corrosion. Standards and resistivity-based specifications mainly address aerated or disturbed soils. For piles driven into undisturbed soils, resistivity, pH, drainage, soil type, and chemical composition do not reliably establish corrosiveness.<br /><br />Steel corrosion requires an electrochemical process, including anodic and cathodic areas and an electrolyte; dissolved oxygen and chlorides can contribute. Corrosion rates also vary by exposure zone, with splash and low-water zones generally experiencing higher losses than atmospheric, buried, or permanently immersed zones.<br /><br />Durability should be addressed through design rather than resistivity alone. Options include providing sacrificial steel thickness, using higher-grade steel, coatings, marine-grade steel such as A690, and cathodic protection. Higher grades can improve strength and durability and allow lighter piles. Each measure has limitations: coatings have finite service lives, cathodic protection is ineffective in the splash zone, and A690 is not effective in continuous submergence. Protection should therefore be selected for the pile’s exposure zones and maintenance plan.<br /><br />The presentation also reviews steel composition and high-strength low-alloy steel, noting that alloying and grain refinement can improve strength and toughness. Its overall recommendation is to assess corrosion mechanisms and actual exposure conditions, rather than treating low soil resistivity as proof that a driven pile requires maximum corrosion protection.

Keywords

steel-pile corrosion

resistivity

electrochemical corrosion

soil corrosivity

driven piles

corrosion protection

sacrificial steel thickness

cathodic protection

marine-grade steel

exposure zones