Follow us on Twitter Follow us on LinkedIn Like us on Facebook Follow us on Instagram Visit the TPC Store
Search the site




Coatings Industry News

Main News Page

New Bay Bridge May Be Under Microbe Attack

Tuesday, January 30, 2018

More items for Quality Control
More items from North America

Comment | More

According to a report from a San Francisco-area television news station, the new span of the San Francisco-Oakland Bay Bridge is experiencing corrosion at unexpected rates, possibly brought on by microbes.

Bay Bridge
Dllu, CC BY-SA 4.0, via Wikimedia Commons

The new eastern span of the San Francisco-Oakland Bay Bridge, which opened less than five years ago, is exhibiting signs of microbiologically influenced corrosion.

NBC Bay Area’s investigative unit reported Thursday (Jan. 25) that the California Department of Transportation is looking into why pitting appears to be afflicting welds on the piles securing the new eastern span in the bay floor. The new bridge cost $6.4 billion to build, opened in 2013 and has been subject to scrutiny over cost overruns and potential material deficiencies in the years since.

MIC on Bridge Piles

The latest problem, corrosion that Caltrans says is proceeding at an accelerated rate in some areas, could potentially cut the bridge’s projected 150-year service life by a third, NBC reports. The station acquired public records indicating that Deepwater Corrosion Services Inc., of Houston, inspected piles that were covered in barnacles, finding that under the biofouling was pitting corrosion that appears to be more serious than anticipated.

Caltrans told the station it is investigating whether microbes in the bay could be responsible for the corrosion. Microbiologically influenced corrosion (MIC) is common in structures such as wastewater facilities and sewers, where bacteria convert hydrogen sulfide gas into sulfuric acid, which speeds corrosion. While MIC is less prevalent on bridge projects, NBC reports that the study indicated that there are microorganisms on the bay floor that could speed corrosion.

Bay Bridge

Caltrans is looking into why pitting appears to be afflicting welds on the piles securing the new eastern span in the bay floor.

The corrosion on the bridge’s 13 piles, according to the news station, could reduce the bridge’s service life by up to 50 years.

Caltrans did not immediately respond to a request for a copy of the Deepwater Corrosion report on Monday (Jan. 29).

Past Project Problems

After the completion of the new span in 2013, several reports of issues with the structure surfaced. In 2014, corrosion was found on cable strands; the same year, water intrusion was found in an area that was supposed to be watertight.

In 2015, cracking was found on improperly grouted anchor rods, and last year, Caltrans defended the bridge’s materials after reports that discarded steel from the project showed yield strengths lower than what was required on the job.

The old eastern span of the Bay Bridge was replaced due to concerns about its safety under earthquake conditions; part of the span infamously collapsed during 1989’s Loma Prieta earthquake, killing one driver. While the western span—a suspension bridge reaching from San Francisco to Yerba Buena—was retrofitted for seismic durability, Caltrans determined that the eastern span should simply be replaced.


Tagged categories: Bridges; Caltrans; Corrosion; Microbiologically Induced Corrosion (MIC)

Comment from Fred Wittenberg, (2/4/2018, 7:45 PM)

Hydrogen sulfide is anaerobic. S.F.Bay isn't a sewer, so why isn't there enough oxygen in it? I've commented before regarding the problems with this bridge; and they just keep occurring?

Comment Join the Conversation:

Sign in to our community to add your comments.

DeFelsko Corporation
PosiTector SST Soluble Salt Tester
Measures the concentration of soluble salts on metal surfaces. Use with all Bresle patch types including the reusable, adhesive-free PosiPatch.

HoldTight Solutions Inc.
Our HoldTight®102 salt remover & flash rust
preventer prevents flash
rust by removing surface contaminants. Contact us
for your nearest distributor.
(800) 319.8802

SAFE Systems, Inc.
Custom blast rooms
by SAFE Systems
Don't waste time and money "making do" with a "standard" design. Let us work with you to design and build the system that best fits your requirements.
Call 1-800-634-7278

Industrial Vacuum Equipment Corp.
Hurricane Vacuums
& Dust Collectors
Vacuum and dust collector hose, filters and related accessories.

Fischer Technology Inc.
DUALSCOPE®FMP100 with DataCenter IP
Transfer customized inspection plans from PC to FMP100 using step-by-step guidance with prompts and pictures throughout the measurement procedure

SABRE Autonomous Solutions
The ALPHA1 provides reliable results consistently allowing you to cost your next job with confidence.

KTA-Tator, Inc. - Corporate Office
• Coating failure analysis
• Independent testing
• Accelerated weathering testing
• Abrasives Testing
• Oil & Gas Material Qualification
• A2LA Certificate #2455.01
Contact: Rob Leggat
at 412-788-1300 x176

Sauereisen, Inc.
SewerGard® 210XHB
• 300 mils in a single coat by plural component equipment
• Fast Setting
• 100% Solids Epoxy
• Chemical-resistant barrier for municipal wastewater environments

ARC / A.W. Chesterton Company
Superior Impact & Wear Resistant Lining
100% solids, impact resistant, ceramic reinforced, epoxy/urethane hybrid lining for severe abrasive wear and impact resistance.

Jotun Paints Inc.
Jotun Jotachar 1709
Mesh-free passive fire protection epoxy designed to protect against hydrocarbon pool fire scenarios for up to four hours as defined in the ANSI/UL1709 standard.


Technology Publishing Co., 1501 Reedsdale Street, Suite 2008, Pittsburgh, PA 15233

TEL 1-412-431-8300  • FAX  1-412-431-5428  •  EMAIL

The Technology Publishing Network

Durability + Design PaintSquare the Journal of Protective Coatings & Linings Paint BidTracker

EXPLORE:      JPCL   |   PaintSquare News   |   Interact   |   Buying Guides   |   Webinars   |   Resources   |   Classifieds
REGISTER AND SUBSCRIBE:      Free PaintSquare Registration   |   Subscribe to JPCL   |   Subscribe to PaintSquare News
MORE:      About   |   Privacy policy   |   Terms & conditions   |   Site Map   |   Search   |   Contact Us