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Re: fracture critical welds

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>Aren't all welds fracture critical? No
AASHTO/AWS D1.4-2002 12.2.2 defines FRACTURE CRITICAL MEMBERS "Fracture Critical members or member components are tension members or tension components of bending members (including those subject to reversal of stress), the failure of which would expected to result in he collapse of the bridge.  The designation "FCM" shall mean facture critical member or member component.  Members and components that are not subject to tensile stress under any condition of liveload shall not be defined as fracture critical."
Addition requirements are charpy impact testing (CVN) of base metals and weld metals.
The fabricator must be certified under the AISC Quality Assurance program, Category II, Major Steel Bridges with Fracture Critical Rating.
Each State's DOT (or equal) has their own criteria of what is and is not FC along with the required Charpy Impact testing requirements (CVN), dependent on temperature.
Out of the last 236 bridges that I was involved with only 1 was a fracture critical project (AREMA project - Railroad)

Richard M. Beldyk, PE, NSPE, CWEng, CPE
Professional Engineer - Delaware 6788, Maine 9987, Maryland 26594, Michigan 6201048734, Ohio E-66691, Oklahoma 20523, Pennsylvania PE061240, Virginia 37138
Registered Member - International Registry of Professional Engineers - Certificate IR101
AWS Certified Welding Engineer - Certificate  0009Eng
AFE Certified Plant Engineer - Certificate 4582
----- Original Message -----
Sent: Wednesday, August 28, 2002 11:08 PM
Subject: RE: fracture critical welds

Aren't all welds fracture critical?  If not, why use them?  ;)
Jake Watson, P.E.
Salt Lake City, UT