Expert: Replace At Risk Bay Bridge Rods

Caption

Close

Image 1 of 20

John Fisher is a member of Caltrans' peer-review panel for the Bay Bridge eastern span project.

John Fisher is a member of Caltrans' peer-review panel for the Bay Bridge eastern span project.

Photo: Max Whittaker/Prime, Special To The Chronicle Image 2 of 20 News media at new eastern section of the Bay Bridge at Pier E-2 which contains the found fractured anchor rods, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less News media at new eastern section of the Bay Bridge at Pier E-2 which contains the found fractured anchor rods, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on ... more Photo: Michael Macor, The Chronicle Image 3 of 20 Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (one of eight clusters of rods ) as CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (one of eight clusters of rods ) as CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday ... more Photo: Michael Macor, The Chronicle Image 4 of 20 Caltrans deputy director Will Shuck holds a section of bolt removed from the new Bay Bridge in preparation for testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less Caltrans deputy director Will Shuck holds a section of bolt removed from the new Bay Bridge in preparation for testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the ... more Photo: Max Whittaker/Prime / Special To The Chronicle Image 5 of 20 Image 6 of 20 The eastern side of the old, (left) and new eastern section of the Bay Bridge as construction continues while CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less The eastern side of the old, (left) and new eastern section of the Bay Bridge as construction continues while CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, 2013, in ... more Photo: Michael Macor, The Chronicle Image 7 of 20 Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (one of eight clusters of rods shown at bottom left ) as CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (one of eight clusters of rods shown at bottom left ) as CalTrans conducts a boat tour of the impacted areas of ... more Photo: Michael Macor, The Chronicle Image 8 of 20 Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (at bottom center ) as CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less Pier E-2 of the eastern section of the new bay Bridge which contains the fractured anchor rods, (at bottom center ) as CalTrans conducts a boat tour of the impacted areas of the bridge on Wednesday Mar. 27, ... more Photo: Michael Macor, The Chronicle Image 9 of 20 News media at Pier E-2 of the new eastern section of the Bay Bridge which contains the fractured anchor rods, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less News media at Pier E-2 of the new eastern section of the Bay Bridge which contains the fractured anchor rods, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on ... more Photo: Michael Macor, The Chronicle Image 10 of 20 Image 11 of 20 A section of bolt removed from the new Bay Bridge in after breaking during a Charpy V notch impact test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less A section of bolt removed from the new Bay Bridge in after breaking during a Charpy V notch impact test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 ... more Photo: Max Whittaker/Prime, Special To The Chronicle Image 12 of 20 A section of bolt removed from the new Bay Bridge in undergoes a Rockwell hardness test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less A section of bolt removed from the new Bay Bridge in undergoes a Rockwell hardness test at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the ... more Photo: Max Whittaker/Prime, Special To The Chronicle Image 13 of 20 Workers continue the construction of the new eastern section of the Bay Bridge, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on Wednesday Mar. 27, 2013, in Oakland. Inspections found that 30 large bolts on the new eastern span of the Bay Bridge have fractured. less Workers continue the construction of the new eastern section of the Bay Bridge, as CalTrans conducts a boat tour of the impacted areas of new eastern section of the Bay Bridge on Wednesday Mar. 27, 2013, in ... more Photo: Michael Macor, The Chronicle Image 14 of 20 Bolts are covered in paper and duct tape on an earthquake shock absorber beneath the new Bay Bridge Monday August 26, 2013 where bolts were found to be broken.Hours before the schedule shutdown of the Oakland-San Francisco Bay Bridge, CALTRANS officials showed off the shims which will allow the new span to open near Labor Day 2013. less Bolts are covered in paper and duct tape on an earthquake shock absorber beneath the new Bay Bridge Monday August 26, 2013 where bolts were found to be broken.Hours before the schedule shutdown of the ... more Photo: Brant Ward, The Chronicle Image 15 of 20 Image 16 of 20 Steel shims, shaped like rectangles, (behind bolts) above the earthquake shock absorbers will allow the bridge to open. Hours before the schedule shutdown of the Oakland-San Francisco Bay Bridge, CALTRANS officials showed off the shims which will allow the new span to open near Labor Day 2013. less Steel shims, shaped like rectangles, (behind bolts) above the earthquake shock absorbers will allow the bridge to open. Hours before the schedule shutdown of the Oakland-San Francisco Bay Bridge, CALTRANS ... more Photo: Brant Ward / Brant Ward / The Chronicle Image 17 of 20 A machine carves out the teeth of the saddles that will fix the broken bolt problem on the Bay Bridge during a media tour of the XKT Engineering facilities in Vallejo, Calif. on July 31, 2013. A machine carves out the teeth of the saddles that will fix the broken bolt problem on the Bay Bridge during a media tour of the XKT Engineering facilities in Vallejo, Calif. on July 31, 2013. Photo: Ian C. Bates, The Chronicle Image 18 of 20 An XKT worker carves out grooves for the the saddles that will fix the broken bolt problem on the Bay Bridge during a media tour of the XKT Engineering facilities in Vallejo, Calif. on July 31, 2013. An XKT worker carves out grooves for the the saddles that will fix the broken bolt problem on the Bay Bridge during a media tour of the XKT Engineering facilities in Vallejo, Calif. on July 31, 2013. Photo: Ian C. Bates, The Chronicle Image 19 of 20 A section of bolt removed from the new Bay Bridge for testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch steel rods that broke during construction. less A section of bolt removed from the new Bay Bridge for testing at Caltrans TransLab in Sacramento, California, May 9, 2013. Caltrans is testing the so-called "2010 rods", following the failure of 32 three-inch ... more Photo: Max Whittaker/Prime, Special To The Chronicle Image 20 of 20 Expert: Replace at-risk Bay Bridge rods 1 / 20 Back to Gallery

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.

LATEST SFGATE VIDEOS

Now Playing:
  • Bus dash cam video shows near-miss with car sfgate
  • Biking across frozen Caples Lake near Kirkwood, Calif. sfgate
  • Helicopter and crew installing a new chairlift at Bear Valley ski resort sfgate
  • MLK march in San Francisco SFGate
  • Georgia firefighters share dramatic rescue video sfgate
  • Vacaville police dog breaks in new shoes sfgate
  • Black Comix Arts Festival 2018 SFGate
  • Five vans for your #vanlife sfgate
  • See First: Take control of your Facebook News Feed sfgate
  • Bay Area woman reunited with her dog after it was stolen sfgate

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."

Jaxon Van Derbeken is a San Francisco Chronicle staff writer. E-mail: [email protected]

Source : http://www.sfgate.com/bayarea/article/Expert-Replace-at-risk-Bay-Bridge-rods-4532939.php

Loading...
Expert: Replace at-risk Bay Bridge rods
Caltrans officials acknowledge more cracked rods in Bay Bridge
Are molasses and corn syrup fix for broken Bay Bridge rods?
Bay Bridge Bolts Show More 'Ominous' Cracks, May Not Even Be Safe To Drive On
Fishing Report for Dec. 12: Stripers calling from San Luis to the Delta and the Bay
On Infrastructure, California Goes Back to Basics
Kahn, Horn: More questions need answers about Zilwaukee Bridge construction foul-up after MDOT investigation finds no fault
Pretzel Logic: 192 picks from a Fantasy Football Expert Draft
Mega projects need expert management
Loading...