Seattle bridge reopens after sinkhole

SEATTLE – Two vehicles that fell into a sinkhole caused by a water main break in Seattle were towed to street level Thursday to allow city workers to repair a 10-by-15-foot gap in the University Bridge’s foundation.

Bikes and pedestrians were allowed back on the bridge at 7 a.m. and cars started moving across the span around 3 p.m., said Gregg H. Hirakawa, spokesman for the city Transportation Department.

“We’re still asking motorists to use caution in the area” because there’s still a lot of work being done, he said.

Hirakawa said the corner of the bridge where city workers poured a slurry of concrete and sand was designed to carry a maximum load of 300 tons – when it’s not missing part of its foundation.

“We do have a section of the bridge that is being supported by open space, and air is not a good support,” he said.

The bridge, used by 31,400 vehicles daily, didn’t collapse because most of its weight was distributed elsewhere, Hirakawa said.

The flood of water Wednesday also opened up a sinkhole 8 to 10 feet deep and 30 to 40 feet wide that swallowed two cars and closed the lone street to more than 50 houseboats.

City workers have turned a walkway into a temporary road to give houseboat residents and repair crews access to the area, Hirakawa said.

It will take a few more days to repair the sinkhole, Hirakawa said.

The 2-foot-diameter cast iron pipe may have been leaking since Tuesday, but the rupture became evident shortly after 7:30 a.m. Wednesday when a muddy cascade emerged near the southern foundation of the bridge, which was closed within minutes.