Leaks have been detected on the rebuilt eastern section of the San Francisco-Oakland Bay Bridge in California, despite the use of caulking in an effort to solve the problem.

News service Sourcable reports that the internal leaks caused by bolt holes for guard rails were first detected last winter. This led the Bay Area Toll Authority to caulk around 900 holes in a bid to plug the leakages, the news report said.

The caulking proved inadequate during recent stormy weather. Water reportedly accumulated within the splay chambers, which are sealed rooms that play a role in securing the main bridge cable to the new span.

Splay chambers need to be kept dry to prevent corrosion of the anchor rods that attach the main cable to the span.

Despite the ongoing leaks, the use of dehumidifiers has kept moisture levels inside the splay chambers within acceptable levels. The California Department of Transportation (Caltrans) reportedly has measured humidity within the rooms at 38%, just below the 40% threshold at which corrosion begins.

Leakages and corrosion problems reportedly have long been concerns for the rebuilt eastern section of the Bay Bridge, which opened in the fall of 2013 at a cost of more than $6.5 billion.

Bill Casey, a senior Caltrans engineer for the eastern section, was reported as saying the chambers were affected by water during the construction process for roughly a year, from December 2011 to December 2012.

Humidity levels within the splay chambers rose last winter as a result of the leaky bolt holes. This caused puddles to form during stormy weather at a time when the dehumidification system was not yet properly operating.

According to news reports in April 2014, two types of corrosion were found within one of the splay chambers: white rust produced by a protective layer of zinc, and the reddish-brown rust of the underlying steel.

This rust can create risk for the integrity of the bridge as it makes the cable strands and rods susceptible to cracking, particularly given the vibrations caused by heavy traffic on the span.

In response to these reports, officials planned to caulk all the leaks prior to the start of northern California’s rainy season. Caltrans reportedly will consider the task of plugging the leaks to be a repair and maintenance issue.

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