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NU Helps CTA Measure Bridge Span Strength

By Chuck Sudo in News on Nov 29, 2010 10:00PM

Another interesting article in today's Tribune from transportation columnist John Hilkevitch. This one looks at how CTA bridge spans, particularly on the northern reaches of the Red Line, have long exceeded their lifespan thanks in large part to the lower payload that the "L" cars carry (these bridges were originally built to handle steam rail).

In an effort to determine just how deteriorated these bridge spans are, CTA President Richard Rodriguez reached out to Northwestern University's Infrastructure Technology Institute after reading a story about how NU researchers were measuring the strain on highway bridge spans. Nu started measuring the Devon-Sheridan bridge in July to measure how much the structure bends when trains pass over. What the data that was collated so far indicates is that, so far, the structure is tolerating the daily strain of train traffic. The data can also be used to determine what types of stopgap measures can be utilized for the Devon-Sheridan and similar bridges.