Transcript group 17.ppt

The Wexford Bridge.
Group 17
Vincent Carey
Amy Fitzpatrick
Patrick Gibbs
Micheal McCarthey
History of the Bridge.
• Constructed: 1959.
• Location: The River Slaney, Co. Wexford.
• Span: 383m.
• Bridge Type: Prestressed Concrete
Cantilever.
Why was the Bridge Replaced?
• Excessive Chloride Ion Content.
• Irreparable Structural Damage, to:
– Concrete Reinforcement,
– Prestressing Achors,
– Lamination & Spalling.
What is Chloride Ingress?
• The Corrosion of Reinforcement Steel.
• How?
• 2 Stages in the Process.
– First Stage:
– Transport Within/Without to Reinforcement
Areas
– Due to Chloride Content in Water
What is Chloride Ingress?
– Second Stage:
– Destroys Protective Passivation Layer.
– Provided Oxygen Present Starts to Corrode
Bars
– This is called “Pitting Corrosion”.
– Causes Significant Mechanical Stress in Steel
Solution For Our Bridge?
• Damage to Extensive.
• Demolish and Rebuild.
• 10 Week Construction For New Bridge
New Bridge
• Continuous Steel Grider Deck
• Composite Concrete Slab
• Max Fabrication Off Site (time)
The New Wexford Bridge
How To Prevent Chloride Ingress in
the New Bridge?
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OPC better then SRPC
Temperature Of Cement
Corrosion Inhibitors
Hydropholic Treatment
Paint For Exposed Steel(20 year Marine)
The End.