OAKLAND -- Taxpayers looking to place blame for the missteps behind the catastrophic failure of steel bolts on the new Bay Bridge will find plenty of targets in a blistering 102-page report unveiled this week and on the table for debate at a public meeting Wednesday.
Caltrans, bridge contractor American Bridge/Fluor Enterprises and consulting engineers at T.Y. Lin International/Moffatt & Nichol all made decisions that led to the fracture of the large anchor rods in key seismic stabilizers, the Toll Bridge Program Oversight Committee concluded after its investigation.
As a result, the bridge opening has been delayed for weeks or months while the engineers and contractor bolster the broken bolts with an exterior steel cable and saddle clamping assembly. That work will not be completed until December, pushing the bridge opening months into the future unless officials are persuaded that a flawed new span is still safer than the old one.
"It is an impressive confession of fault, especially considering that one of the three authors is the director of Caltrans," said retired chairman and materials science Professor Emeritus Charles McMahon Jr. from the University of Pennsylvania. "The knowledge that could have prevented this screw-up has been available in the literature for decades. All it would have taken is a couple of phone calls. Unfortunately, you have to understand that a problem exists before you can set out to avoid it."
Detroit metallurgist Cory Padfield, who is writing a textbook on fastener failures, concurred.
"Fasteners are often considered standard parts that don't require a lot of scrutiny until something goes wrong," Padfield said. "What happened on the Bay Bridge shows that if you are going to build a $6 billion bridge with expensive fasteners, you had better have someone on staff who is aware of all the information available on the subject."
The investigation is the three-member committee's most public and forceful display of its oversight role since the Legislature formed the panel in 2005. In addition to Caltrans Director Malcolm Dougherty, the committee includes Metropolitan Transportation Commission Executive Director Steve Heminger and California Transportation Commission Director Andre Boutros.
"This is exactly the kind of report I had hoped to receive -- a candid, forthright analysis into the causes of the failures of those rods in terms of the materials and the selection process," said Orinda Mayor and Metropolitan Transportation Commission Chairwoman Amy Worth. "This type of transparency will allow policymakers and the public to have confidence when we open the bridge."
The oversight panel also addressed in its analysis the outcome of testing on the 2,210 fasteners that did not break, finding no cause for immediate concern.
But pending the results of long-term corrosion testing that has not yet started, the panel flagged 736 anchor rods in seismic stabilizers adjacent to those that broke for possible replacement or reduced tension levels.
These bolts are made of especially hard steel and are tightened to 70 percent of their capacity, making them vulnerable to long-term stress corrosion and failure.
The oversight panel puts the bulk of the blame on Caltrans and the consultants for the chain of events that culminated in March, when 32 out of 96 steel anchor rods snapped a few days after contractors tightened them down. The rods are embedded in seismic stabilizers called shear keys in the pier east of the main tower.
Metallurgists point to a well-known phenomenon that affects hot-dip galvanized high-strength steel under heavy loads, in which hydrogen atoms infiltrate steel's latticelike molecular structure and leave it brittle and vulnerable to fracture.
The path to failure began with the consultants hired by Caltrans in 1997 to design the bridge.
The engineers needed ultra-strong¿ steel that would work within the span's unique architecture and withstand the incredible stresses and strains expected under daily traffic load and from earthquakes.
The oversight panel found emails showing that Caltrans and the consultants were aware of the steel's susceptibility to embrittlement but preventive measures were not sufficient.
The engineers had modeled the Bay Bridge specifications after guidelines on the earlier Richmond-San Rafael bridge retrofit.
But the Richmond bridge bolts were only snug-tight and their loads are nowhere near as high the Bay Bridge. The greater the loads, the greater the susceptibility for embrittlement.
Among their other findings of fault with Caltrans and the design team:
The committee singled out American Bridge/Fluor Enterprises for failing to protect the rods that broke from five years of wet weather. The water may have contributed to the failure.
They also panned Caltrans for its inability to locate quality assurance tests for the main span tower's marine foundation.
"Such information is vital not only for an investigation of materials failure such as this but for routine maintenance and major rehabilitation of the self-anchored suspension span over its 150-year life," the committee wrote.
More details about the Bay Bridge's delayed opening will be hashed out at the Bay Area Toll Authority meeting at 10 a.m. on July 10 at the Metropolitan Transportation Commission offices at 101 Eighth Street in Oakland.
Can't attend? An audio stream of the meeting will be available at www.mtc.ca.gov/meetings/schedule/.
A copy of the Wednesday presentation slideshow will be posted at baybridge.org/rods at 10 a.m. Wednesday.
The full Toll Bridge Oversight Committee bolt investigative report is available at www.mtc.ca.gov/projects/bay_bridge/A354.htm.