The traffic on Highway 43 near Portland took a turn this month, another step toward the early 2016 completion of the new Sellwood Bridge over the Willamette River.

Traffic on the northbound lane of Highway 43 now uses the new interchange ramps associated with the Sellwood Bridge project and the southbound through lane travels under the new bridge, a process that will continue until next summer, even after the new bridge opens. Moving traffic in this way has allowed work to begin on the west ramps of the interchange, with the first steps including excavation and lagging for the west retaining wall.

The effort to replace the 88-year-old crossing with a new seismically sound structure included shifting the old bridge 66 feet to the north for use as a detour bridge, allowing the new bridge to fill in where the old bridge previously crossed.

All this off-water work ensures that Highway 43 keeps moving its 30,000 daily vehicles during the construction process. Once completed, the Highway 43 interchange with the Sellwood Bride will features a new two-level structure.

For the river work, the new bridge has plenty of ongoing construction efforts too. Six of the 11 concrete deck pours for the main bridge span have wrapped and two more pours—lasting up to 20 hours—should finish at any point. With crews completing tasks all across the bridge, the tower crane will leave the work zone around Thanksgiving and electricians will install power lines in the main arch spans and in the conduits inside the bridge sidewalks.

Owner Multnomah County says that general contractor Slayden-Sundt Joint Venture has the project over 85 percent complete, with the new bridge expected to open in early spring 2016.

Follow Tim Newcomb on Twitter at @tdnewcomb.