Corrosion Case Studies
Highway 3 - Northfield, Minnesota
Four decorative light poles fell within a three-day period in 2011 without apparent extreme, external forces of wind or impact, making corrosion the likely culprit. All the poles were installed in 2004.
Wind from a storm may have factored in on the three of the four collapses but corrosion near the base of the poles is suspected of weakening the structures to a failure point. Seventy-two of the decorative light poles were installed on both sides of Hwy. 3 and several side streets during the reconstruction of Hwy. 3 in 2004 and 2005. After examination of those 72 poles it has been determined 51 along Hwy. 3 have experience significant corrosion and deemed a hazard.
Light Poles - Massachusetts
The structural integrity of 4,000 light poles is in questions after state DOT inspectors found highly corroded bolt connections on some massive poles hanging over the Mass Pike.
And on one day in 2012 two poles on a major bridge completely failed and had to be removed. Other poles have been observed to have completely broken from their base due to corrosion at the bottom of the pole. As a result over 4,000 poles are set for inspection, costing the Massachusetts taxpayers hundreds of thousands of dollars.
Some poles on Route 128 were visually examined and found to have completely rusted bases such that you can see right through them to the other side. Some poles are just missing from their bases and have exposed wires.
Tappan Zee Bridge - New York
Steel, like concrete, is vulnerable to the corrosive effects of rainwater, especially when it mixes with road salt used to melt snow. The 2009 engineering assessment found that the Tappan Zee’s rate of deterioration is “unusually high.” The bridge’s drainage system was designed to dump water onto the substructure below the highway, causing major corrosion in crucial components like its “stringers,” horizontal beams that hold up the deck, and joints. Replacement deck joints manage to last only about ten years. Particular concern surrounds the stringers along the causeway section, which the assessment identified as “high risk.” Major cracking has also been observed on the causeway’s outer columns, reappearing soon after repairs. - (New York Times, Jan. 13, 2013)
Some of these issues were addressed in the repairs done in 2008, shown in this galvanized steel case study.
Parking Structure - Johnstown, Pennsylvania
In 2008, despite an appearance telling otherwise and the public being told the Washington Street parking structure was safe, it collapsed. Parts of the second and third floor of the 37 year old garage collapsed, damaging dozens of cars parked inside. Rusted steel beams were visible throughout the garage and is suspected of contributing in part to the failure. The city will pay about $390,000 to raze the structure and assess whether the city budget and insurance proceeds will allow for rebuilding. In any event, the city will be without a sorely need location for parking of public official vehicles.