Interstate bridge's crack likely dates back to 1970s [View all]

LITTLE ROCK Ark. (AP) — A crack in a steel beam that forced the closure of the Interstate 40 bridge connecting Arkansas and Tennessee for three months likely began when the span was fabricated in the 1970s and went undetected for years, a report by Arkansas' Transportation Department released Thursday said.

A forensic investigation by an outside firm hired by the department said the crack occurred in a weld between two plates during the bridge's fabrication. Those welds were more susceptible to cracking because of the type of steel and welding method used then, the department said.

“In all likelihood the cracking in the weld occurred within hours of its completion but was not detected by any post-weld repair fabrication testing and remained unchanged for a number of years," the department's report said.

The crack had been visible in 2016, and an inspector who had missed it was fired by the department in May. The report said the weld fracture initially was not visible by conventional inspection and was not caught by an ultrasonic inspection in 1982.

https://www.yahoo.com/news/report-interstate-bridges-crack-likely-203502049.html