Causes, Prevention, & Designing for Corrosion Resistance on Sheet Pile Structures by Roll Form Group

Causes, Prevention, & Designing for
Corrosion Resistance on Sheet Pile Structures
Compiled By: Ryne Allen, B.S.CE, P. E.

Objectives
Causes
• What variables make steel corrode &
deteriorate?
Prevention
Objectives
• What options and processes are available
on the market to help extend the steel life?
Designing for Corrosion Resistance
• After choosing a prevention process, what
should the expected life be?

Causes
Objectives
• Soil Conditions/Properties
• Water level, water type, & splash zone
• Pollution/Contamination
• Exposure to Air
• Time
Corroded Spud Pile

Causes
Corrosion is the destructive attack of a metal by
chemical or electrochemical reaction with its
environment (Revie & Uhlig, 2008 p. 1)
Causes
• Soil Conditions/Properties
• Water level and water type
• Pollution/Contamination
• Exposure to Air
• Time
Corroded Spud Pile

Causes
Soil Conditions & Properties
•Soil Grain size: bigger grain size allows for
more air exposure at face of structure,
therefore exposing to corrosion. aka
porosity
•pH of soil: more acidic soils will
be more corrosive (pH < 7)
•Disturbed Soil:
Clean backfill contains more usable
oxygen. Oxygen promotes corrosion.
Therefore disturbed/backfill material
can promote corrosion along face of
wall
Porosity Visualization
http://www.renewedlivinginc.com/how-your-ph-determines-your-overall-state-
of-health/#

Causes
Water level & Water Type:
•Sea water is more corrosive than fresh
water due to the salt content.
•Tidal bodies of water are more corrosive
than stationary bodies
•Groundwater flow has an effect on
corrosion
Corroded walls in Okinawa, Japan
http://www.acotec.be/ProjectDetail.aspx?id=738c2290-be56-4700-8365-
02eed905bdc0

Causes
Pollution & Contamination:
•Pollution can break down and make soil
more acidic, increasing corrosion
probability.
•Contaminated soil with different
concentrations of chemicals can have
negative effects on chemical interaction
between soil and steel wall
•Vegetation built up on steel influences
corrosion
Replacing Contaminated soil in Florida

Causes
Exposure to Air:
•Oxygen is needed in order to make the
chemical reactions to yield corrosion.
(oxidation)
•The salt in Salt Air by a coastal region
allows for accelerated corrosion.

Causes
Time:
•The longer there is exposure, the more
damage

Prevention
• ASTM A572 Bare/Black Steel Properties
• Sacrificial Thickness
• Coating Systems
• ASTM A690 Mariner Grade Steel
• ASTM A123 Hot Dip Galvanizing
• Cathodic Protection
Objectives

ASTM A572 Bare Black Steel
Prevention
Bare/Black Steel Properties
include:
•Carbon-Manganese for strength
and ductility
•Only corrosion resistance is
trace Columbium (0.05%)

Coating Systems
• Coal Tar Epoxy Coating
with/without zinc primer coats
• Most common corrosion prevention
system
• Specified on majority of marine
applications
• Generally placed to ~5ft below mud
line to assure high corrosive area is
covered
• Accepted by many US DOT and
Waterway agencies
• Cost effective, ~$1.50 – $2.95/SF
of covered area
• Easily damaged & Compromised
• Proper maintenance/touch-up will
greatly extend life
South Florida Water Management Bulkhead in Palm
Beach County, FL
Prevention

Galvanizing
• Hot-Dipped (Zinc) Galvanizing
• Meets ASTM A123
• Aesthetically Pleasing
• Recommended for non-tidal,
freshwater applications
• Salt in Seawater has negative
chemical reactions with Zinc and
negates corrosion prevention
• Galvanizing sheet pile generally
full length
• Generally, lengths greater than 40’
require “double dipping”, and
increase costs.
• Not cost effective for longer/heavy
sheets due to cost based on
weight vs. coating area
Prevention
Hot Dipped Galvanized Steel Sheet Pile

Cathodic Protection
• Works when a sacrificial anode is attached to sheet pile wall
that “absorbs” the electrochemical cell from the environment
• Though cathodic protection works, “burned out” anodes must
be replaced in order to maintain working condition; else
corrosion will start
• Labor intensive installation
• Expensive Installation, Maintenance, & Operations
• Requires annual to bi-annual
inspection/maintenance/replacing
Prevention

Prevention
Increased Thickness
• No extra handling/secondary applications; no additional maintenance
• Life span is affected by multiple environmental conditions
• Life can be somewhat determined vs. other applications when applying the
Eurocode3
• Using the Eurocode3, weight increases as a result of thicker steel, thus
increasing total cost (typically 50-80% for weight and costs)
• Typical product lines of sheet pile producers do NOT carry thicknesses
exceeding 0.500”
• In situations where greater than 0.500” required, secondary fabrication
(cover-plating) or special rolling may be needed, dramatically increasing
costs.

• Using Engineering principals,
Allowable Moment Capacity
is a function of Section
Modulus and yield strength
(Grade)
• Increasing Grade (Carbon
content) may reduce section
size/thickness while
maintaining structural
integrity
• Increasing Grade of sheet
pile will keep thickness the
same; counteracts corrosion
over time by starting with an
initial higher strength
• Deflection must still be
considered & checked
Prevention
Increased Grade

• Meets ASTM A690
• Adding Copper & Nickel increase corrosion prevention properties.
• ASTM: “Substantially greater resistance to seawater ‘Splash Zone’
corrosion than ordinary steel”
• Grade extra charge; longer lead time.
Prevention
Mariner Grade Steel

Design Life and Cost Comparisons:
Given a jobs specific condition, environment, and budget, the following
table represents our general thoughts and recommendations:
Corrosion Protection
Approach
Costs Durability/Life Availability/
Installation Time
Cathodic $$$$$$
Coatings $$$
Galvanizing $$$$$
Sacrificial Thickness $$$$
Increase Grade/Yield Strength $
A690 Mariners Steel $$
Designing for Corrosion Resistance

References
References:
Revie, R. Winston & Uhlig, Herbert H. (2008). Corrosion and Corrosion
Control (4th ed.). Hoboken, New Jersey: Wiley, John & Sons,
Incorporated
Elaine & Nevin. (2012). pH Chart. http://www.renewedlivinginc.com/how-your-
ph-determines-your-overall-state-of-health/#.
Acotec. Corroding Sheet Pile Wall. http://www.acotec.be/ProjectDetail.aspx?
id=738c2290-be56-4700-8365-02eed905bdc0.
ASTM Standard A690/A690M-07, 2007, “Standard Specification for High
Strength Low-Alloy Nickel, Copper, Phosphorus Steel H-Piles and Sheet Piling
with Atmospheric Corrosion Resistance for use in Marine Environments”
ASTM International, West Conshohocken, PA, 2007, DOI:
10.1520/A0690_A0690M-07, www.astm.org.

For more information, please contact:
ROLL FORM GROUP
Heavy Construction / Road Transportation
heavyconstruction@rollformgroup.com
Canada: (800) 233-6228
North Eastern USA: (570) 504-5880
South Eastern USA: (904) 287-8000
Mid-West USA: (800) 762-7631
Western USA: (916) 989-6720

Causes, Prevention, & Designing for Corrosion Resistance on Sheet Pile Structures by Roll Form Group

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