Dashing rumors to the contrary, officials with the state’s Department of Transportation hold fast to their belief that work on the Kummer Bridge will be finished in time for the hectic Fourth of July traffic.
One rumor was floated about last week, suggesting that work will take a year or more. Some report hearing that the entire bridge will be replaced, a project that will keep the Green River span out of commission for years.
Not true, Department of Transportation officials say.
“We continue to see good progress,” said Russ East, assistant regional administrator for the DOT. “We really want this road open for the Fourth of July.”
DOT staff gathered the morning of April 8 with public officials from Black Diamond to explain what’s being done and what chores still need to be completed. Strolling through the work site on the south side of the Green River Gorge, visitors in hardhats and safety vests stood approximately 35 feet below the bridge deck.
The bridge is a crucial link in state Route 169, connecting Enumclaw and points south with Black Diamond and destinations to the north. While there are other ways to make the trip, the Kummer Bridge is the easiest, most direct route.
The bridge has been closed since November, after being deemed unsafe by DOT geotechnical engineers.
East said the decision came after heavy rainfall caused a pier on the southern slope to slip about a half-inch in one wet weekend. The state agency has known of the bridge deficiencies for some time and attempted a couple of low-cost alternatives earlier in 2008. When those failed to solve the problem, the decision was made to close the bridge and launch a major fix.
The root of the problem goes back thousands of years. The bridge was built on the edge of an ancient landslide, East said earlier this year when he gave separate updates to the Enumclaw and Black Diamond city councils. The entire southern edge of the Green River Gorge is shifting east and toward the river, he said, adding that no one could have been aware of the geologic condition when the bridge was built in 1932.
The problem has been evident for years to SR 169 motorists who have noticed that the bridge deck and the highway are not exactly aligned – not by design, but rather due to the west-to-east movement of the entire hillside.
The April 8 visitors to the work site were warned that the bridge is a busy place these days, with assorted bulldozers, excavators, forklifts and concrete trucks moving in and out. On a dry day, there are still random wet spots and baseball-sized rocks make for unsteady footing.
When all the visitors had arrived, East explained that the biggest component of the $15 million project is the installation of 55 vertical concrete shafts. They line the bridge approach on the east side and are intended to prevent further erosion. The columns range up to 90 feet tall and most extend 20 feet into pre-drilled bedrock.
Other work will be done, East said, to help drain groundwater away from the unsteady southern slope.
When that work is done, crews will haul in approximately 27,000 yards of material to replace the soil previously excavated. Once the ground is returned to bridge level, a new stretch of roadway will be added.
When everything is complete, East said, travelers won’t notice much of a difference. All the work will be hidden underground.
Reach Kevin Hanson at firstname.lastname@example.org or 360-802-8205.