The floating bridge of highway 520 in Washington State is nearing retirement after being continuously in service since 1963. With three years remaining until a new bridge can be in place state officials are racing to replace corroded cables, 15 of the 58 anchor cables which range in age from 18 to 33 years old. These large steel cables connect the bridge pontoons to anchors on the lake floor. These corroded cables pose a serious problem as they have the potential to snap in a windstorm. These cables prevent sudden movement of the bridge, and provide a stable surface for cars and without them drivers would find the bridge nearly impossible to navigate. If one or more of these cables snapped in a windstorm it could mean long term bridge closures which would be devastating to residents who rely on the bridge. More than 60,000 vehicles cross this span over lake Washington every day. This bridge stretches 1.5 miles from Seattle to Medina and is the longest floating span in the world.
New pontoons will arrive on Lake Washington in 2014, but for many of these weakened corroded cables, that is not soon enough. As the first few cables were retrieved out of the waters of Lake Washington and their rusted, frayed, splintered shreds were wound around spools and taken away, crews were impressed with just how frayed and corroded some of the cables were.
An aging infrastructure nationwide means many states and municipalities are dealing with corrosion issues, which cannot afford to be ignored. In many cases close monitoring can save millions of dollars by allowing workers to keep old bridges in safe working order until their replacements are ready.
Recent testing found a small pipeline problem near Stanford University. To be more specific, the pipeline is located near Hanover Street on Page Mill Road. Corrosion was the reported cause of the problem. The pipeline experienced a deterioration of the protective coating on the pipe which lead to a hole developing. The Pacific and Gas Company reported that workers were able to apply a protective sleeve around the affected area. They also reapplied a new protective coating over it as well.
Another section of the pipeline was also assessed. This section was very close in proximity to the previous repair described. In order to fix this section, workers needed to cut out the section of pipe and weld in a new piece. The cause for this damaged pipeline was reported as unknown.
Both sections of pipelines were finally tested by operating under pressures that were 1.5 times the maximum pressure limit. Both sections of the pipeline ran into problems during these last final tests. However, further repairs were made and both pipe sections eventually passed the required tests.
An associate of the Stanford office of Land, Buildings Real Estate stressed the importance of these testings. He also stated the importance of gas pipeline system safety.
PG&E was unable to uncover records of previous tests done on the pipelines. These initial tests were then ordered by the California Public Utilities Commission due to the lack of testing proof. Under code, PG&E is required to test all sections of undocumented pipeline. Until the tests are processed, the pipes are required to operate at reduced pressures. More testing is required by PG&E and will continue throughout the winter season.
