Briefing Report: A Bridge Too Far?

Wednesday, May 15, 2013

“With six months left before the Labor Day opening of the new Bay Bridge span, Caltrans has already managed to break a significant portion of the most expensive public works project in California history.” -- Contra Costa Times, 5/2/2013

In an era that has seen California’s transportation infrastructure go from being the envy of the free world, to being one of the most congested and dilapidated transportation networks in the nation, perhaps it should come as no surprise that the voters have lost confidence in the behemoth Department of Transportation (Caltrans) who, despite spending $13 billion a year and employing 20,000, seem incapable of delivering the projects, maintaining the system, and improving the facilities that are the backbone of the state’s economy.  The general frustration with Caltrans has been a common refrain in Sacramento.  However, in the past several years that frustration level has morphed into a fear that the agency is no longer capable of delivering projects in a timely, cost effective manner that meet the safety requirements of California’s seismic geography.  Nothing illustrates this growing alarm better than recent revelations about the Bay Bridge.

Background

On October 17, 1989, the Loma Prieta Earthquake struck the San Francisco Bay Area. The damage this moderate earthquake caused highlighted the seismic vulnerabilities of all the state-owned toll bridges, especially the Bay Bridge. Caltrans initiated research projects soon after the Loma Prieta Earthquake to understand better the vulnerabilities of the state-owned toll bridges because of their structural complexity and uniqueness.

Based upon the hazard and vulnerability studies, Caltrans determined to seismically retrofit seven of the nine state-owned toll bridges in the Bay Area. In addition, Caltrans deemed replacement to be the most cost-effective, long-term retrofit strategy for the eastern span of the San Francisco-Oakland Bay Bridge.  In 1997, the Legislature enacted SB 60 (Kopp) and SB 226 (Kopp) to establish a funding program to complete the seismic retrofit of all the state-owned toll bridges, estimating the cost for the entire program at $2.6 billion, including $1.36 billion for a new Bay Bridge.  The legislation provided a three part funding package: a $1 toll increase on all state toll bridges, State Highway Account (SHA), and revenues from the passage of the Seismic Retrofit Bond Act of 1996 (Proposition 192).

In 2001, a Caltrans report determined that the cost for the Bay Bridge was $1.32 billion higher than expected.  AB 1171 (Dutra, 2001) was signed into law providing an additional $643 million in state funding and authorized extension of $1 in additional tolls on Bay Area bridges, for 30 additional years.  AB 1171 also amended the specific estimate of the cost for the retrofit of the Bay Bridge to $2.6 billion and set in statute the Self-Anchored Suspension (SAS) design chosen by the Bay Area as its signature bridge, despite significant engineering challenges and additional costs. 

By fall of 2004 it had become apparent that even these funding estimates were grossly insufficient to cover the actual cost of the project. Governor Schwarzenegger proposed amending the proposed signature span design, replacing it with a significantly cheaper, traditional skyway design that would be far less expensive and significantly less difficult to engineer.  This proposal was defeated in the Legislature, where Bay Area Democrats developed an alternative funding plan that would allow for additional tolls to pay for cost overruns, would shield the state from any additional financial responsibility, and would dismiss any chance of a more modest design.

Today, almost 25 years after the Loma Prieta Quake, the total cost of the bridge has grown to a staggering $6.4 billion.  What is worse, seemingly at every step, the project has been plagued by engineering problems and system failures that have further compromised the voters’ confidence in Caltrans ability to deliver the project, and more importantly to guarantee the safety of the new structure. The most recent issue to come to light has been the failure of 32 bolts.

Nuts & Bolts

The eastern span of the Self-Anchored suspension bridge contains seismic devices called bearings and shear keys.  The bearings allow the road deck to move slightly during a seismic event, while the shear keys prevent the deck from moving too much.  The four bearings, two beneath each deck, and the four shear keys, one beneath each deck, and two beneath each cross beam connecting the decks, are bolted between the roadways and a concrete cap beam with steel anchor rods.

“In March 2013, 32 of the 96 high strength steel anchor rods for two shear keys in Pier E2 of the new self-anchored suspension bridge failed within days after they were tensioned.  Since then, Caltrans has been unable to articulate why these huge high strength steel anchor rods failed.”  (SAS Pier E2 Hot Dip Galvanized Grade BD Anchor Rod Failures, prepared for MTC by Yun Chung, April 21, 2013 (hereafter, MTC Report)).

Who Knew?  … err, umm, well… Apparently, Caltrans

The issues with hardened steel are not new in the engineering world.  In fact, the subject has been studied exhaustively at the federal level.  In 2004, Caltrans adopted bridge design specifications that require anchor bolts to be manufactured to standards established by the American Society for Testing and Materials International (ASTM).  ASTM fastener standards include tensile strength (the maximum tension a bolt can support prior to or coinciding with its fracture), ductility (the ability of a material to deform before it fractures), and hardness (a measure of a material’s ability to resist abrasion and indentation).  According to the Federal Highway Administration (FHWA), ASTM and Caltrans own standards, the harder and stronger the bolt, the more susceptible it becomes to hydrogen embrittlement (HE).

“The confusion surrounding these anchor rod failures reflects the lack of expertise by Caltrans in materials engineering, and, specifically, in the nature of HE failures of high strength steels.  Caltrans specification requirements were inadequate and allowed these failures to occur.  What is more troubling is that Caltrans has been oblivious to the possibility of these anchor rod failures due to HE during the 150 year design life of the new bridge.” -- (MTC Report)

Although these standards are not black and white, the compiled research all points to the fact that they should not be used, particularly in a marine environment.  Caltrans’ own bridge design specifications specifically preclude the use of bolts as strong as the 288 bolts on the Bay Bridge.  “If Caltrans had established a conservative maximum hardness for the surface of the Pier E2 anchor rods, no anchor rod failures would have occurred.” (MTC Report)

The rationale for using materials, that the combined expertise at the federal and state level all suggest would fail, under precisely the conditions under which these bolts are being used, simply defies logic.  And yet, they are in the bridge, they are failing, and now Caltrans engineers are scrambling to develop a fix to avoid a predictable problem of their own creation.

 “Safety is not job one, it’s the only job we’ve got.”

-- Steve Heminger, Executive Director of Metropolitan Transportation Commission

Throughout the countless issues associated with the Bay Bridge, from faulty welds, to missing concrete testing data, to the current issue with the bolts, Caltrans and the Bay Area planners involved with the development and construction of the bridge have said all the right things, claiming that their only interest was in delivering a safe bridge.  However, the credibility of these protests is compromised after every new incident.  In addition, a close examination of the history of the planning process makes it clear that safety was not always the first concern.

When initial studies were conducted after Loma Prieta, experts came back with three alternatives.  The first was retrofitting the existing facility, which although the quickest and surest fix, was dismissed because it was considered too expensive.  Ironically the price tag for that retrofit was estimated to be between $250 million and $1 billion.  The second option was a skyway construction model, using tested technology that would be the most cost-effective and safest approach.  This option was dismissed because Bay Area officials, most notably then Mayor of Oakland, Jerry Brown, wanted a world-class bridge, a signature facility.  As a result, the third option was selected, a self-anchoring suspension bridge.  Although technically feasible, this option involved the engineering of the world’s longest SAS facility in the most challenging of geological circumstances.

From the sidelines, it appears that the safety and feasibility of the project may have taken a back seat to the primary goal of developing an aesthetically pleasing product.  As a result, engineers were being forced to work at the outer limits of the possible to ensure that they could deliver a product that met the design criteria while also preserving the look of the facility.  This is one possible explanation for the use of bolts that violated Caltrans design specifications, as reported in the Sacramento Bee, “Caltrans officials told the Chronicle that the Bay Bridge had different project-specific criteria and that the manual’s ‘generic specifications are for run of the mill bridges.” (Sacramento Bee, May 2, 2013) 

Now What?

“When the full potential of these HE failures during service with the 256 not-yet broken anchor rods in Pier E2 is known, it could deal a serious blow to the trust of the earthquake worthiness of the new bridge and any remedial designs or solutions to counteract the failed and yet-to-fail anchor rods”  -- (MTC Report)

Caltrans is currently at work choosing between two potential engineering fixes for the breaking bolts as it is simultaneously testing the viability of the rest of the bolts on the bridge.  These engineering work-arounds will have to provide the same seismic safety for which the bolts were originally engineered.  Under different circumstances these fixes might not merit any particular scrutiny; however, with the scheduled opening of the bridge only a few months off, the public can be excused for lacking confidence that Caltrans can salvage the situation.

When the Bridge finally does open to great fanfare at least six years after the first estimated completion date, will the public be confident that this is the safest bridge in the world?  Will the public believe that the $6.4 billion it has poured into this flashy bridge was money well spent?  Evidently, this doesn’t really concern Governor Brown, one of the loudest original advocates for the “world class bridge.”  When asked about the problems with the bolts, Governor Brown was reported to have said, “S#@t happens!... There are very professional engineers that are looking at this thing, and when they're ready to give us their report, I think the public will be satisfied.” (Sacramento Bee, May 7, 2013)

OK, at least there’s one person that still believes Caltrans!

For more information on this report or other Transportation issues, contact Ted Morley, Senate Republican Office of Policy at 916/651-1501.