Bay Bridge - NIST Presentation Rev 5
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Transcript of Bay Bridge - NIST Presentation Rev 5
NeutroN ImagINg of HydrogeN IN a354 grade Bd Steel aNcHor rodS
by Lisa Thomas, P.E.Metallurgist, Berkeley Research Company
To assess the risk of environmental hydrogen embrittlement cracking to other A354 Grade BD anchor rods
do this...
Measure H concentration in the failed rods, near the fracture and
in the top ends
meaSure HydrogeN coNceNtratIoN
Neutron Tomography Gamma-Ray Activation
generate 3D maps of hydrogen concentrationacross the entire rod cross-section
NIST Center for Neutron Research
Dr. Daniel HusseyDr. Thomas H. Gnaeupel-HeroldDr. Rick L. Paul Dr. Richard M. LindstromDr. David L. Jacobson
NIST scientists:
all tHat IS requIred:
3-millimeter thick discs
specimens from both ends of the S1 & S2 rods & from any other rods that are available
H gradIeNt IN top eNdS vs. H gradIeNt IN Bottom eNdS
“Wa s HE c r a c k i n g E x c lu s i v E to c o r r o s i o n o f b ot to m t H r E a d s?”
informs tHE managEmEnt stratEgy of
otHEr rods
These studies using neutron imaging to measure hydrogen content in A354
Grade BD steel fasteners of this size have not been done!
It will be invaluable, not only for theSAS Bay Bridge but for infrastructure
projects around the world!
In Closing...
Thank You.