LOS ANGELES Gerdau Long
Steel North America says that the steel it produced to create
anchor rods for the San Francisco-Oakland Bay Bridge that have
since failed met the specifications "it was ordered to."
A spokesman for San
Franciscos Metropolitan Transportation Commission (MTC)
said last week that U.S. subsidiaries of Brazilian steelmaker
Gerdau SA produced the steel that was turned into rod for the
bridges new east span.
The metallurgical condition of
the 2008 anchor rods was "less than ideal," with a
"higher-than-normal susceptibility" to hydrogen embrittlement,
Malcolm Dougherty, director of the California Department of
Transportation (Caltrans), said during a meeting of
Californias Toll Bridge Program Oversight Committee. The
same description was used in a Caltrans analysis of the
In March, 32 out of 96
galvanized ASTM A354 grade DB rods manufactured in 2008 by
Dyson Corp., a Painesville, Ohio-based fastener systems
fabricator, broke when they were tightened to connect seismic
safety devices called shear keys (
amm.com, April 1). Gerdau Long Steels St.
Paul, Minn., facility produced the steel used to make the rods,
the MTC spokesman told AMM.
A second batch of 192 rods
produced in 2010 and put into service hasnt shown the
same problems, according to initial indications (
amm.com, May 17), but they are now being tested
for integrity. The steel for those rods was produced by Monroe,
Mich.-based Gerdau Special Steel North America.
A decision on whether to replace
the 2010 rods is expected at the May 29 meeting of the Bay Area
Dyson has maintained that the
metallurgical report on the 2008 rods, which were supplied to
project contractors American Bridge Co., Coraopolis, Pa., and
Fluor Corp., Irving, Texas, "exonerates" the fabricator because
it determined the rods met the requirements of ASTM A354 grade
A spokeswoman for Tampa,
Fla.-based Gerdau Long Steel North America, who said the
company takes great care to produce steel to the "most
demanding standards," confirmed it produced the steel used for
both the 2008 and 2010 anchor rods, but said in a statement it
"met the specifications it was ordered to."
Gerdau said it was "looking into
this matter," but noted that "there are many possible root
causes, given the various steps associated with the fabrication
and placement of steel products, and these root causes are
being investigated by multiple parties."
The metallurgical analysis found
that the principal source of internal hydrogen in the steel was
"likely the freeing of trapped residual hydrogen by the
upquenching effect of hot-dip galvanizing." The MTC spokesman
later said the galvanizing was performed by Monnig Industries
Inc., Glasgow, Mo.
Monnig vice president Jason
Monnig declined to comment.
Dougherty said during an
oversight committee meeting that Caltrans currently
doesnt allow the use of A354 rods that are galvanized on
"standard" bridge applications. But Brian Moroney,
Caltrans chief bridge engineer, later said that its
not uncommon for a bridge to contain several "deviations" from