For a second week, south-metro commuters will navigate around ramp and lane closures on Interstate 35W at Hwy. 13 in Burnsville.

Over the last two weeks, road crews have twice had to assess and repair damage to the Hwy. 13 bridge, likely caused by trucks carrying too-tall loads smacking into its girders.

“This is one of our lower-clearance bridges,” said Kent Barnard, spokesman for the Minnesota Department of Transporation. “With a truck going 60 to 65 mph, there likely was a bang and a jerk, and the driver kept going,” Barnard said, pointing out that no one reported hitting the bridge.

A crew painting the bridge on Saturday noticed the latest crack in an outside girder, which set off the latest round of ramp closures, he said.

Last week, crews closed the ramp from southbound I-35W to northbound Hwy. 13 to repair damage likely caused by a blow from a truck carrying a load over the legal height limit, Barnard said. Traffic was back to normal there by Friday, but then crews noticed new damage on Saturday and ramp and lane restrictions returned.

The damage isn’t anything “major,” Barnard said, but the crack must be repaired so it doesn’t expand or rust. “The bridge is still safe,” he said. The closures are needed to allow crews room to work, Barnard said.

The ramp from northbound Hwy. 13 to northbound I-35 reopened midway through Monday’s rush morning rush hour but the ramp from southbound I-35W to northbound Hwy. 13 remains closed until crews finish their work, Barnard said.

Motorists can likely expect additional lane closures this week once repairs get underway, he said.

Drivers who use the ramp from southbound 35W to northbound Hwy. 13 are being detoured. A possible alternate route is to use County Road 42 to northbound I-35E and back to Hwy. 13.

The ramp from northbound Hwy. 13 to northbound 35W is heavily used, especially since many motorists are using Hwy. 13 to avoid the traffic tangles created by lane closures on Hwy. 169 over the Bloomington Ferry Bridge. That project is scheduled to be completed by Friday.