Bay Bridge SAS Foundation is 'Safe,' Says Peer Review Panel
A peer review panel investigating the seismic safety inspection practices of a former Caltrans engineer concluded that the Bay Bridge east span foundation in question is safe and that it “meets or exceeds the state-of-practice and will result in a safe and reliable performance.”
Duane Wiles, a Caltrans safety technician in its Foundation Testing Branch, was fired in November for falsifying safety tests on other Caltrans projects. Wiles also tested the Bay Bridge’s Self-Anchored Suspension span T-1 foundation, which caused a regional uproar as well as calls for hearings by the state assembly.
Steve Heminger, the executive director of the Bay Area Toll Authority and chairman of the Toll Bridge Program Oversight Committee (TBPOC), requested an independent review of the safety practices on the foundation via the Seismic Safety Peer Review Panel (SSPRP).
The panel’s report, issued last week, concluded that it was highly unlikely that any data falsification occurred in the testing of the T1 foundation piles. The letter was signed by the panel’s chairman, structural engineer Joseph Nicoletti, along with members Dr. Frieder Seible, dean of the Jacobs School of Engineering at UC San Diego; Dr. I.M. Idriss, an independent consulting geotechnical engineer and professor of civil engineering at UC Davis; and Dr. John Fisher, a professor of civil engineering at Lehigh University.
The report addresses the SAS pile design, structural capacity and seismic safety and responded to redundancy in design, rebar congestion, testing requirements (e.g. gamma test pipe clearances and spacing) and use of gamma-gamma logging versus cross-hole sonic logging.
“The foundation technician in question participated in the gamma-gamma log nondestructive testing on eight of 13 piles,” the report said. “For all of these eight pile tests, other Caltrans foundation testing technicians or supervising engineers were present. Since discovery of the falsification of data at other bridges, the test records for the T-1 piles were investigated by Caltrans engineers for inconsistencies in data and time stamping and no inconsistencies were found.”
The panel further found that the performed gamma-gamma log testing showed good results and even the cross-hole sonic log testing conducted independently by the contractor showed the expected good construction quality.