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New Bay Bridge Faces Corrosion Challenges: Safety Concerns Emerge

The iconic new Bay Bridge, stretching from Oakland to San Francisco, has faced ongoing structural issues since its initial corrosion signs in 2011. Despite its 2013 opening and a projected 150-year service life, the bridge is already showing signs of potential structural instability, raising concerns for its long-term safety.

This $6.5 billion suspension bridge is known for its unique design featuring a single cable composed of 137 steel strands, forming an impressive tower that supports the bridge structure. The cable, secured on the bridge's eastern edge, is encased in chambers designed to protect it from corrosive environmental effects, including water and marine air. However, recent investigations have unveiled visible rust on the cable's rods and strands inside one of the protective chambers, jeopardizing the bridge's intended 150-year service life.

Corrosion signs have been confirmed through laboratory tests, posing a substantial threat of structural damage well before the bridge's planned lifespan. Ongoing issues, including water leakage into the chambers, are exacerbating the problem.

A noteworthy discovery was made earlier this month, revealing that a vast majority of the 423 steel rods anchoring the bridge's tower to its base were submerged in water due to inadequate grout filling in protective sleeves. A staggering 95% of these rods had approximately 1-2 inches of water, and 17 rods were improperly filled. Identifying the water source remains a challenge, but it is feared that bay water intrusion could be responsible.

Corrosion prevention and repair efforts are anticipated to cost toll payers over $25 million, with an additional $20 million spent on assessing the risk of further failures akin to the 32 rods that snapped in 2013. Effective sealing of the chambers, drying the cable strands using hot, dry air to remove residual moisture, and potential rod replacement are among the proposed solutions to halt corrosion's progression.

Some bridge builders are exploring the use of non-corrosive carbon fiber rods and cables to fortify bridges. These carbon fiber components, which are ten times stronger than steel, offer resistance to oxygen, water, and chemicals, making them a durable choice for bridge construction and repair.

The Bay Bridge's structural integrity issues underscore the significance of innovative materials like carbon fiber to ensure the longevity and safety of critical infrastructure projects.

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