The completion of the last major bridge deck pour on the Sellwood Bridge in Portland marks a major milestone for the project to construct a new 2,000-ft span across the Willamette River.

Building the new bridge, which will be the second new span across the river since 1973—the first new span opened in November with the welcoming of Tilikum Crossing—required the sliding of the original 1925-built bridge in order to make room for the new structure.

With construction starting in December 2011, the 1,976-ft span will cost just over $317 million. The TY Lin International-designed steel deck arch bridge will come with three sweeping arches built by a joint venture between Slayden Construction Group and Sundt Construction.

Finishing the final major deck pour allows crews to move forward on relatively smaller tasks, such as sidewalks and parapet construction, all in preparation for the bridge’s planned early spring 2016 opening.

The first deck pour was performed on Oct. 20.

Next up for the project is a “topping-off party” on Dec. 18. Along with the two new driving lanes across the majority of the structure, the bridge will have two 12-ft-wide sidewalks, two 6.5-ft-wide bicycle lanes and new lane options at each landing—both the west and east ends widen to four lanes.

The original bridge opened on Dec. 15, 1925, as a four-span continuous deck-truss. The main span runs 300 feet. The seismically unstable structure was slid 66 feet to the north for use as a detour bridge during the construction process, allowing the new bridge to fill in where the old bridge previously crossed.

Follow Tim Newcomb on Twitter at @tdnewcomb.