Expert: Replace at-risk Bay Bridge rods

[Leroy N. Soetoro]

http://www.sfgate.com/news/article/Expert-Replace-defective-Bay-Bridge-
rods-4532939.php

Caltrans needs to examine hundreds of at-risk rods on the new eastern span
of the Bay Bridge and replace any that are hard enough to be vulnerable to
cracking, says an internationally known expert who serves as an adviser to
the state agency.

John Fisher, 82, an emeritus professor of civil engineering at Lehigh
University and member of Caltrans' peer-review panel for the project, said
the state's decision to use galvanized, high-strength steel rods was "not
well-thought through" because such metal can crack when exposed to the
elements.

"I would have certainly urged them to take another course," said Fisher,
who joined Caltrans' eastern span advisory panel in 2009. That was several
years after Caltrans made an exception to its ban on galvanized, high-
strength metal for bridge construction and ordered such rods to be
installed throughout the eastern span.

Fisher, who has spent decades studying failures of U.S. steel structures,
including the World Trade Center in 2001, urged that Caltrans test all
bridge rods that are under high stress and replace any that register
toward the upper levels of hardness.

Such large, threaded steel rods are rated on a numeric scale - the higher
the number, the harder the steel, and the more vulnerable it is to being
invaded by corrosion-causing hydrogen found in the environment. Fisher
said any rods registering above 34 on that scale should be replaced. The
acceptable range for these rods is considered to be between 31 and 39.

Hedging on deadline

Caltrans documents suggest that the state agency received hundreds of such
rods for the eastern span. Thirty-two designed to hold seismic-stability
structures in place have already broken.

It is unclear how long replacing hundreds of rods would take or how much
it would cost. The $6.4 billion structure is scheduled to open to traffic
Sept. 3, but officials have hedged recently on whether that target will be
met.

Caltrans is planning tests to gauge the long-term risk from 2,200
additional rods on the span, but Fisher said the agency should simply
replace all the rods at high stress if field tests show they fall into the
danger zone of hardness.

Fisher is one of three members of the eastern span peer-review panel, a
group of experts who review Caltrans' decisions and provide advice.

He has published more than 275 articles in scientific and engineering
journals and is the co-author of an authoritative 1974 book on high-
strength steel rods and bolts. Before joining Caltrans' peer-review panel,
he assessed welding problems on the bridge project for the Federal Highway
Administration.

'Valuable' opinions

Caltrans Director Malcolm Dougherty said in a statement that "Dr. Fisher's
opinions are now, just as they have always been, valuable and
independent."

He said the agency would make sure that any defective rods are replaced
with ones that are made with more "restrictive specifications and extra
testing."

Brian Maroney, Caltrans' chief engineer on the bridge project, said he was
aware of Fisher's view on replacing rods if they exceed 34 on the hardness
scale.

"We haven't decided to do that yet - that is one alternative, one
consideration," Maroney said. "We might do that."

Caltrans had prohibited using high-strength, galvanized rods on bridges
since 2000 because of the long-recognized risk that they could crack under
the heavy loads typically carried in bridge projects.

Dougherty told the state Senate's transportation committee last week that
his agency made the call in 2002 to deviate from its ban because of the
high demands placed on the rods by the unusual single-tower suspension
span.

'Eyes wide open'

He said the agency had done so with its "eyes wide open" and after
"absolute due consideration" of the risks involved. He said the state had
tried to keep the rods from being invaded by hydrogen during the
galvanization process, when the metal is dipped in molten zinc to guard
against rust.

Dougherty did not, however, say whether Caltrans had taken steps to
prevent the rods from cracking in the elements. The 32 rods that failed
when workers tightened them in March are thought to have been invaded by
hydrogen after being put in place on the span in 2008.

Fisher said in a telephone interview from his home in Bethlehem, Pa., that
Caltrans should simply have lowered the hardness of steel to begin with,
setting a maximum of 34 on the hardness scale. The bolts that snapped in
March had an average rating of 37.

"I think they understand at this point that they should have done
differently," Fisher said. "I'm not 100 percent sure why they looked at
this the way they did."

Federal warning

He pointed out that the federal government issued guidelines in 1991
against using high-strength steel above a hardness of 33 in bridges. "It's
puzzling that the warning was not given more attention," Fisher said. "I
am surprised that this was done without putting some limits on it."

He added, "The irony (is), the team that they (Caltrans) put together
included not just civil engineers but material science and corrosion
people. It brought together all those disciplines."

In his appearance before the state Senate committee, Dougherty said a host
of engineers and materials experts had been involved in the decision to
use the rods.

"This was not an issue of us using these bolts and taking an additional
risk," Dougherty said. "We had positive experience of using these bolts
and galvanizing them for corrosion protection."

However, one of those involved in the decision, a former senior corrosion
engineer for Caltrans, said in an interview that he had repeatedly warned
bridge builders about the cracking risk of high-strength steel in the
marine environment.

"We brought that up many times," said Rob Reis, who left Caltrans in 2012
after 21 years to work for the state Department of Water Resources.

Tests weren't done

Reis said he had urged that the rods be tested for potential vulnerability
to cracking before being installed on the eastern span. Caltrans officials
have acknowledged no such tests were done, in part because the rods were
so thick that the required bending would be difficult.

Maroney confirmed that he has seen documents that showed Reis was
concerned about corrosion and wanted the rods tested for embrittlement
before being put in the bridge.

Maroney added that he was "pretty sure" that bending the 3-inch-diameter
rods would have been possible. As for why it wasn't done, he said, "We are
digging into that right now."


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