Part of an "L'' joint that holds the asphalt in place between the temporary bridge and permanent roadway came loose Saturday morning and the right lane of the bridge was closed for about two hours while crews welded the joint back into place and spread new asphalt, Transportation Department spokesman Kris Olsen said.
The rest of the joints will be inspected between 8 p.m. Saturday and 5 a.m. Sunday.
A portion of the Skagit River Bridge collapsed on May 23 after a truck struck some critical steel supports. A temporary span was opened about a month later. A new $6.87 million permanent bridge is being constructed over the river.
The 58-year-old bridge carries an average of 71,000 vehicles a day over the Skagit River on I-5, Washington's major north-south roadway between Oregon and Canada.
The replacement bridge is expected to be in place in early September.
Federal transportation investigators believe an oversize load struck the bridge last month, causing a portion of it to collapse into the river and taking two vehicles with it. Nobody was seriously injured, but the failure has continued to disrupt transportation.