Interstate-29 will remain closed until at least Friday morning while engineers look over damage created when a semi struck an overpass. Public Safety Department spokesman Jim Saunders says a southbound semi hit the overpass, just south of Sergeant Bluff. Fortunately the driver wasn’t hurt but there was “significant” structural damage to the overpass, Saunders says. In the southbound lanes officials aren’t sure it’s safe to have vehicles passing under it right now. So the lanes are closed for the rest of the day — and night. From just north of Sergeant Bluff, at the 144 mile marker, down to the 135 interchange, lanes are closed at least until Friday morning. They’re diverting traffic from the Interstate, at the interchange just north of Sergeant Bluff, onto the old Highway 75, now known as K-45, which runs parallel to the interstate, so Saunders says it should minimize the inconvenience. Traffic engineers are on the way to do a thorough inspection of the bridge and see that it’s structurally sound enough to allow traffic to resume.