The committee in charge of the $6.4-billion San Francisco-Oakland Bay Bridge retrofit project announced July 8 that the previously scheduled Labor Day opening of the structure’s new East Span has been postponed until around December 10 of this year.
The Toll Bridge Program Oversight Committee (TBPOC) also released the findings of its investigation into 32 of the 96 A354 grade anchor bolt rods on the structure's eastern span that broke when crews tightened them in March. The investigation found that the rods, fabricated in 2008, did indeed fail due to hydrogen embrittlement, which requires a source of hydrogen, susceptible material and tension.
The report states that the contract specifications for the East Span did not consider the unique requirements of the seven different rod locations on the SAS Bridge – locations above and below water, and at different tension levels. “One specification was inappropriately applied to all locations,” it reads.
The investigation also found there was inadequate consideration to allow for alternative types of steel for the rods, “inadequate consideration given to the combined effect of high-strength rod material requirements and corrosion protection,” and “inadequate consideration of alternative corrosion protection treatments, given well-known concerns about the risk of hydrogen embrittlement from hot-dipped galvanizing of A354 grade BD rods.
“In particular, alternative treatments such as Geomet, or greased and sheathed, or painted solutions should have been more fully considered depending on the various sizes and applications. A life cycle cost analysis should have been prepared for the various rod alternatives and the various methods of long-life corrosion protection,” the report states.
Further findings found that Pier E2, where the failed rods where placed, should not have allowed for water to collect during the construction process; that more extensive pre-testing for the potential of hydrogen embrittlement should have been conducted; and that not nearly enough written records of rod testing and selection, and the construction process were created.
And then there is the blame, which the report spread throughout involved parties, including Caltrans, the owner/operator; T.Y. Lin International/Moffatt & Nichol Design Joint Venture, the Engineer of Record; American Bridge/Fluor Joint Venture, the contractor for the SAS Superstructure; and Kiewit/FCI/Manson Joint Venture, the contractor for the SAS E2/T1 Marine Foundation.
While the TBPOC sorts through its conclusions, American Bridge-Fluor Joint Venture is continuing to build the innovative steel saddle retrofit on the east pier to take up the support from the failed bolts. The contractor estimates this will take approximately five more months to complete.The TBPOC says it will select a bridge opening date based upon actual completion of the east pier retrofit work, weather windows, traffic impacts and other information as it becomes available.
I hope the person designing the this bridge...
Why do none of these articles ever mention...
The failure of the rods can be seen as a cautionary tale of the hazards of applying "experience".<br/><br/>No doubt the fact that bolts given this treatment were performing well on anot...