Nation’s Bridges Face Increase Scrutiny In light of Wednesday’s I-35 Minneapolis bridge collapse, officials are scrambling to …Full article Can Technology Make Bridges Safer? The U.S. Department of Transportation had declared that “no imminent dangers were observed” on I-35 Bridge in Minneapolis. This was …Full article

Hi,

As the country reels from the horrific tragedy that befell in Minnesota this past week, the nation’s bridges must face increased scrutiny to prevent this from occurring again in the future. On Thursday of this week, Transportation Secretary Mary Peters signed off an advisory that was sent by the Federal Highway Administrating, requiring all state transportation departments, the responsible agency, to conduct thorough inspections of all steel-deck truss bridges. This is the specific type of bridge that collapsed in Minnesota this past Wednesday.

According to federal highway officials, in the United States, there are 756 such spans. Constructing steel-deck truss bridges was popular during the late 1800s and early 1900s. There allure was that there were no piers within their structure, just a single span. This allowed freedom for boats and barges, no obstructions, on the waterways below. Construction of these bridges began to fade in the 1940s as engineers became more aware that due to their lack of redundancy–backup structures–these bridges could collapse with the failure of one single component.

The Minnesota bridge that collapsed on Wednesday evening was among the last bridges to be built using this technique. It was built in 1967. Most of these bridges still existing are older than the one that befell in Minnesota. This is frightening.

With the steel-deck truss bridge technique abandoned in the 60’s, currently there remains five popular forms of bridge construction: suspension bridges, cantilever bridges, cable stayed bridges, beam bridges and arch bridges.

All bridges, irregardless of structural construction, are negatively affected with age.

The older the bridge, the more likely they are to have rust, flaking surfaces or erosion eating deeply into or under the main pieces of steel or concrete that hold them up. State transportation departments must immediately begin the inspection process using age of the structure as a critical factor in determining order of inspection.

The training our engineers are receiving must also be assessed. Ironically, only in the field of bridge engineering does the structural engineer design a complete unit of construction and hold a dominant position. All other structural engineers are actually a sub profession with interests and education in some other form of engineering, such as civil engineering.

Throughout America, we must face the reality of our aging infrastructures. Just this past July 18^th, in New York an underground steam pipe exploded in midtown

Manhattan, resulting in one death and numerous serious injuries. The vast majority of the Northeast side of the country was in a complete blackout for days last year, drawing our attention to the state of our national electrical grid. Hurricane Katrina alarmed the country of the status of our levees and dams. In 1993, cryptosporidium bacteria invaded

Milwaukee’s water supply, killing over 100 people and sickening the entire city.

We cannot have a “no-policy-without-a-catastrophe” attitude any longer. It is time our elected leaders and officials realized that aging infrastructure is no joke. There are lives at stake.

Since life has no reset button…tune into this blog and our website daily. Safe Living, Yovette Mumford

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