Every day Islanders head across the floating bridge, mostly unaware of what is below. On each trip, drivers can’t help but feel the distinct buzz of their tires as they cross over the two sets of steel grates set in the roadway.

But now the welded steel ribs that support the weight and control the movement of the massive concrete structure are giving out. Repairs and upgrades will require shutting down the interstate for a total of 43 days next year.

Islanders can expect two three-week closures of the Homer Hadley Bridge when the reversible lanes are repaired next May and the outer roadway is fixed in July. Engineers Russ East and Randy Simonsen told the City Council that traffic will be diverted to the center roadway for the July closure, limiting Island access to the highway at two on-ramps at Island Crest Way and 77th Avenue S.E. During that time, there will be just two exits onto the Island, at 80th Avenue S.E. and East Mercer Way.

“This will have significant impacts and will limit traffic on westbound I-90. It is not going to be easy getting on Mercer Island,” said East.

Under the worse-case scenario discussed, gridlock in the Town Center could result from the closures. Simonsen and East said that WSDOT expects backlogs on the Island and is considering metering on-ramps to stagger traffic.

“This threatens to bring this Island to its knees,” said Councilmember Dan Grausz.

During the May closure, Islanders will lose SOV access in the center roadway as the reversible lanes will be closed to all traffic. Both closures will repair aging and deteriorating expansion joints that connect the floating section of the bridge to the landlocked portions of the highway.

“The reality is we put this off as long as we can,” said East. “We don’t want to do the work in the winter months, during the storm season.”

The joints have required constant repair, East said, as cracks and fatigue were noticed two years after the bridge’s construction in 1989.

“We have been repairing them almost since day one,” East said. “The cracks must be welded to prevent the joints from failing. This ongoing maintenance work is costly and inconvenient.”

The total cost to replace the four expansive joints will be about $7.9 million. Two joints extend across the entire span of both sections of the highway, on both the eastern and western ends, and the entire portions must be closed for the replacement work. The Homer Hadley Bridge is 9,559 feet long. On the outer roadway, the joints are 65 feet long and weigh 65 tons, slightly larger than the joints in the center roadway, which are 42 feet long and weigh 40 tons. A large crane will be used to lower the expansion joints into place. The first phase of the work to be done from May 4 to 23 will occur in the reversible lanes.

Another “pinch point” expected by WSDOT will take place at the lane reduction planned at Bellevue Way just before the East Channel Bridge during the second closure, July 6-28. At that time, the outer roadway will be closed and westbound traffic will be directed onto the center roadway. WSDOT hopes that regular commuters will find alternative routes and minimize the congestion.

“Our goal is to get other people [non-Island residents] to divert so that they won’t go into the corridor by convincing people there are other opportunities,” East told the Council. “We will do what we can to get people to divert. If they don’t, it gets more and more terrible.”

Councilmembers asked WSDOT officials to come back with more information prior to construction. Mayor Jim Pearman stated that he was concerned that emergency vehicles, such as fire trucks and aid cars, would not be able to pass through the expected choke point at Bellevue Way and the westbound express lanes. Mercer Island depends on paramedic services from Seattle or Bellevue, as well as ladder-equipped fire trucks and additional support or large fires.

“That is a vital concern,” Pearman said of retaining emergency vehicle access.

Deputy Mayor El Jahncke and Grausz suggested that WSDOT complete both projects in the summer. While Mercer Island’s Summer Celebration is scheduled to take place during the July closure, Jahncke said that the impact on city and school district employees in May would be rough. A majority of the hundreds of city and district employees live off the Island and commute to work.

“Getting teachers to school is more important than Mariners and Seahawks games,” the deputy mayor said in response to the suggestion that May was preferred over August because of the impact on Seattle sports fans.

Grausz also suggested that Sound Transit offer the North Mercer Park and Ride during the two closures only to Island residents. That way, Islanders would have an easier time riding the bus. Councilmember Mike Grady expanded on the idea of Islanders using alternative means of transportation and suggested that WSDOT find ways to keep the pedestrian and bike path open for the entire duration of the closures. According to East, a detour route will be available during the construction and will be closed for only a few days.

For more information on the highway closures, go to www.wsdot.wa.gov/projects/i90/homerhadleybridgerepair.

COMMENTING RULES: We encourage an open exchange of ideas in the PNWLocalNews.com community, but we ask you to follow our guidelines for respecting community standards. In a nutshell, don't say anything you wouldn't want your mother to read. So keep your comments:

• Civil
• Smart
• On-topic
• Free of profanity

We ask that all participants own their words by registering for an account. It's a simple process that will take seconds and helps keep our comments free of trolls, cranks, and drive-by commenters.

As a community site, we ask that the community help by using the "Flag" button on each comment if they feel the comment has violated the rules. You can also use the up and down arrows on each comment to voice your opinion about that particular comment.

Want to tell us something but you don't want it to be public? Talk to us privately.