Trivia Tuesday, April 21
Last week's answer
Question: The Sherman Minton Bridge, which carries I-64 between Indiana and Kentucky, is a rare example of a double-decked, dual-tied arch bridge. During its recent multi-year rehabilitation, the sequence of the hanger replacement was extremely restricted. Why was the order of operations so critical for the engineering team?
Answer: Because the bridge is "non-redundant" (Fracture Critical), meaning the failure or removal of certain primary members could lead to a progressive collapse.
An inspection by the Federal Highway Administration found the ties of Sherman Minton Bridge to be fracture critical, in addition to the fracture-prone steel used. It was classified as one of the most nonredundant structures, with the bridge's structural stability relying entirely on two tie girders "to acommodate the total thrust imposed by the arch ribs."