OAKLAND -- When water leaks sprung in the decks of the unbelievably expensive replacement Bay Bridge during a recent storm, people asked a logical question: Is that bridge really going to last 150 years?

After all, the steel and reinforced concrete span is outdoors where rain, fog and the salty bay water could ultimately transform the gleaming structure into a rusted hulk. Just look at the old eastern span now under demolition.

Caltrans insists the new span is here for the duration but concedes that water -- or at least, water in the wrong places -- will be an ongoing threat.

Demolition of the old Bay Bridge continues Friday morning, Feb. 21, 2014, in San Francisco, Calif. (Karl Mondon/Bay Area News Group)
Demolition of the old Bay Bridge continues Friday morning, Feb. 21, 2014, in San Francisco, Calif. (Karl Mondon/Bay Area News Group)

"The bridge is literally a battle zone between steel and water," veteran Caltrans engineer Brian Maroney said. "It's a war that we will eventually lose. But we have taken a number of extra measures to fight corrosion, and if we do a good job maintaining the bridge, we can stay ahead of it for 150 years or more."

Not everyone is so sure, given Caltrans' series of water-related setbacks on the span since construction started 10 years ago.

First, water seeped into ducts that held steel tendons used to strengthen the reinforced concrete in the skyway segment of the span.

In March 2013, a third of 96 very large high-strength steel bolts -- 3 inches in diameter and up to 24 feet long -- inside key seismic stabilizers snapped. Experts say pooled water in the bottom of the bolt casings may have contributed to the failures.


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Then the rains came in mid-January, and water leaked into places beneath the travel deck where water isn't supposed to go.

"It looks like incompetence," said Charles McMahon Jr., an engineer and retired chairman and professor emeritus of the Department of Materials Science and Engineering at the University of Pennsylvania.

Water's destructive effect on steel is well-known and preventable, he said.

"Just by looking at something, you should be able to come to the conclusion that you must have seals that last forever," McMahon said. "Once you get water in a crevice, you get corrosion."

The vast majority of the 900 small leaks found in the bridge were along the north side of the span where the crash barriers along the outside edges are bolted onto the travel deck. These connections appear to have been inadequately sealed, bridge engineers said.

Bay Area Toll Authority deputy executive director and engineer Andrew Fremier is tentatively blaming a design flaw. But he recently told local officials that he is awaiting more technical information before he comes to a conclusion or recommends a fix.

"It's fixable, but it may not be easy," Fremier said. "(To properly seal the barrier connections), the contractor may have to reopen the back side of the bridge deck, open the panels and repeat the process in every segment."

On the plus side, Fremier said he saw no evidence of corrosion and very little moisture elsewhere inside the deck during his personal inspection.

Various news accounts have described the bridge as "watertight" -- or supposed to be -- but in reality, Maroney said, the bridge is better described as water-resistant.

The span contains nearly 1 million bolts and numerous holes and joints to accommodate electrical and utility wires, all of which provide countless nooks and crannies for water to gather.

"The term 'watertight' is appropriate for a submarine, not a bridge," said Maroney, the Caltrans engineer. "But we clearly don't want leaks ... and we have taken a number of measures designed to keep water out."

To move the water through and out -- standing water is particularly damaging -- engineers incorporated weep holes, gutters and drain exits in strategic locations throughout the bridge.

Moisture-sensitive areas such as the chambers that contain portions of the main cable and its anchorage contain high-powered dehumidifiers that pull the water out of the air.

Other anti-corrosion measures on the bridge include:

  • In areas such as the splash zone -- where the piers enter the bay and drainage isn't an option -- engineers factored in known oxidation or rust rates and incorporated extra concrete and epoxy-sealed rebar (reinforcing steel bar).

  • The mile-long main cable is slathered in a heavy zinc paste.

  • Every steel surface is coated with a corrosion inhibitor -- typically, zinc -- including those beneath the decks. Exposed steel is also painted. Joints, intersections and connections are caulked.

    Aside from preserving the bridge's structural integrity and extending its useful life, an effective anti-corrosion program reduces maintenance costs. A new coat of paint, for example, is far cheaper than replacing rusted steel, Maroney said.

    Just how much it will cost to ward off the ravages of water and time remains an open question.

    Caltrans has a baseline annual maintenance budget of $850,000 for the Bay Bridge -- eastern and western sides -- that is adjusted based on conditions.

    Early on, little maintenance is expected on the new eastern span. Most of the initial costs will be for inspections and monitoring, said Caltrans spokesman Andrew Gordon.

    But there are still significant unknowns.

    Initial testing results on the span's high-strength steel rods show no evidence of likely failures similar to the breakage that occurred in the seismic stabilizer. But experts could recommend an aggressive and expensive bolt-replacement schedule or add dehumidifiers.

    Engineers must also determine how to fix the leaking decks and ensure they remain sealed, or risk costly corrosion-related repairs and maintenance headaches.

    "We're clearly not done with the bridge yet," Maroney said. "We have a punch list of items we are working our way through."

    The final bolt-testing analysis and projected maintenance budget is expected this summer.

    While engineers will deliver the technical solutions, the man with the sharpest eye on the maintenance question is probably Steve Heminger, who leads the Bay Area Toll Authority and the Metropolitan Transportation Commission.

    The minute the contractors turn over the keys to the bridge to the state, so to speak, the Toll Authority and the toll-payers are on the financial hook for the upkeep.

    "One lesson we have learned is that nothing is perfect even when you spend $6.4 billion," Heminger said. "But we don't want to accept a level of imperfection that will cause our maintenance budget to drain the bank account."