Construction crews installed the last major section of the 520 bridge on Monday, Aug. 24, one of 776 precast, interlocking roadway deck sections that will make up the new 7,710-foot-long bridge, making it the longest floating highway in the world.

Using a barge-mounted crane, crews lowered a 7.5 foot wide, 50 to 60 ton section of roadway into place, marking the end of what Greg Meadows, deputy construction manager for the Floating Bridge and Landings Project, called the last of the big tasks for the project. While the existing Evergreen Point Floating Bridge (commonly known as the 520 Bridge) has been the longest floating highway for the last 52 years, this new bridge will surpass it by 132 feet.

“This is one of the key milestones of the floating bridge project,” he said. “Over the next few months, we’ll be pouring concrete for the road deck, doing electrical work– the smaller tasks that are part of getting this project done.

When it opens, the new 520 floating bridge will be comprised of four general purpose lanes, two HOV lanes, a 14-foot-wide bicycle and pedestrian path, and a shoulder for disabled vehicles. Designed to be able to withstand wind speeds up to 89 miles per hour and resting 20 feet above the water level, it won’t be slave to closures due to high winds and waves like the existing 520 bridge.

“The lower height of the other bridge is more of a typical design, but it would get shut down because of waves and it makes maintenance more difficult because you have to shut down traffic to do work,” said Denise Cieri, Washington State Department of Transportation deputy administrator for the SR 520 Bridge Replacement and HOV Program.

Crews are expecting to finish the bridge on time and just under their initial $4.65 billion spending cap, having just received an additional $1.65 billion in funding from the Legislature to finish the western portion of the bridge and widen roads on the Montlake approach and the Portage Bay section ending at I-5. Whether or not tolls for drivers crossing the new bridge will increase remains to be seen.

When the bridge opens in the spring, the three westbound lanes will narrow down to two lanes upon reaching Seattle.

With the additional funding from the Legislature, however, crews will continue on construction throughout 2017 to first expand the Seattle approach to three lanes until Montlake Boulevard, and then the corridor leading ending at I-5. The same will happen with the eastbound lanes heading towards Bellevue.

“Right now, it really is a very tight, urban area over by Montlake Boulevard,” said Cieri. “This will definitely help alleviate some of that, for drivers, pedestrians and cyclists.”

The last phase of construction will yield a new Portage Bay Bridge, Montlake interchange, better shoulders and sidewalks, and paths for cyclists that will allow riders to make a 23-mile loop from Bellevue, across the 520 Bridge, through Seattle and back over the I-90 Bridge.

Although the recent $1.65 billion in funding did not come from bonds, a portion of the project’s revenue (around $1 billion) does come from tolling on the existing and new 520 bridge. While the state Transportation Commission has planned for another toll increase, but no increase has been scheduled or is in the works at this time, according to Cieri.

The new bridge has an expected lifespan of 75 years, compared to the current bridge’s surpassed lifespan of 50 years.

After the new 520 floating bridge opens, crews will deconstruct the original Evergreen Point Floating Bridge, breaking down and selling the concrete pontoons that make up the base to likely be used for projects like breakwaters and floating piers all over the world.