The collapse of a 40 year old motorway bridge over the Mississippi River in Minneapolis, Minnesota, on 1 August 2007 has reinforced concerns about the condition of much of the US highway infrastructure. Four months earlier, the MacArthur Maze interchange which feeds traffic into the San Francisco-Oakland Bay Bridge in California collapsed after a petrol tanker crashed into a central pier and caught fire.
The US Department of Transport (DoT) immediately advised state highway departments and other owners of bridges of a similar type to the Minneapolis bridge to inspect their bridges because the cause of the failure was unknown.
Many US highways are aging, some 40 to 50 years old, while traffic loads have increased and maintenance budgets have not kept pace. According to DoT figures, about 25% of the country’s nearly 600,000 bridges are structurally deficient or functionally obsolete. Weights and speeds have to be restricted for structurally deficient bridges. Functionally obsolete means they are unsuitable for current loads.
In China, at least 36 people were killed and dozens injured on 14 August when a bridge collapsed in the town of Fenghuang, in Hunan province while workers were removing scaffolding. The Chinese Ministry of Communications has identified 6,300 bridges across the country that are dangerous because of serious damage to “important structural components”, the state run China Daily reported. The paper says the government in Beijing has pledged to fix or rebuild all the damaged bridges.
