WSDOT closed down one northbound lane over crack. In a seven-hour operation, crews placed 3/8-inch steel plates on either side of the beam to stabilize it.

The crack was found on May 5 during a routine inspection. The crack caused "serious concern" because it wasn't there during a previous inspection in 2017. The "stringer" beam was cracked top-to-bottom, according to WSDOT.

"First crews removed the rivets and cut the steel to size. Next they placed it over the defective area and drilled new holes to secure the plate. Finally, they tied the ends together and painted the repair. It may sound simple, but there are many moving, complex parts that come into play, and working from a mobile platform suspended over the water does not make it easy, especially while trying to keep our workers and drivers safe and traffic moving," WSDOT wrote on its blog.

The Nisqually Bridge was built in 1937 for the old SR 99, long before it was needed to carry I-5 traffic. The bridge crosses the Nisqually River between DuPont and Lacey.