Progress continues on the new multi-use path viaduct

From ODOT-

Crews have been hard at work on the new multi-use path viaduct on the south bank of the Willamette River.  The public can now see the latest components rising from the ground: precast and cast in place hammerheads (crossbeams) that will support the path.

Workers constructed these supports by drilling column shafts, placing rebar cages topped with anchor bolt clusters inside each, and then placing concrete. The top-shaft concrete cure for a week before the precast hammerheads are secured to each column with the tightened anchor bolt assemblies.

Two precast hammerheads are installed on the shaft columns, while one shaft on the right awaits anchor bolt clusters.

Workers carefully place a hammerhead atop a shaft.

Crews will soon start building a block retaining wall on the east end of the path to keep the embankment contained.

Next month, they will place box beams, salvaged from the temporary I-5 bridge, that will rest on the hammerheads and act as a base for two inches of asphalt paving to create the final pathway.

Motorists will see increased activity along the north side of Franklin Boulevard just east of the Whilamut Passage Bridge as the box beams are delivered. Trucks will enter and exit the work zone, allowing cranes to offload and install the heavy beams. Please pay close attention to flaggers and expect brief traffic delays.

The first shaft for the viaduct path is under construction.

From ODOT-  By early 2014, improvements to the park paths near the new Willamette River Bridges will be complete.  The most significant change, a new viaduct path on the south bank of the Willamette River, will replace the current path that connects to the south side of Franklin Boulevard, east of the bridges.



Bridge beams reused from the Interstate 5 detour bridge will provide a structure for the realigned path.  The beams will be supported by 14 individual bridge columns spaced along the riverbank.  Rebar and concrete will fill drilled shafts to a depth of at least 10 feet into the bedrock.



We've recently taken the first step in constructing the viaduct, by drilling a shaft beneath the new northbound bridge.  This had to occur now, because the drilling equipment is too tall to fit under the new northbound bridge once it is built.  This may be the only work we do on the viaduct path until this fall.

As you can see, the drill is taller than the new southbound bridge and would not have fit under the soon-to-be-built northbound freeway bridge.

Here, workers line up equipment to place the steel retainer ring, which will prevent dirt and rock from falling back into the drilled shaft.

Arch ribs photo story- part 2 of 4

From ODOT- Over the last few months we've posted photos of work on the Willamette River Bridge, but as the southbound bridge arches near completion, let's look back at how they took shape. We've seen how the crews installed a rebar cage that provides critical strength for the foundation of the bridge. Next we'll explore the point where the arch ribs touch down - a point where we can begin to see the construction of the arch frame.

On top of the drilled shafts that anchor the bridge in place sit custom-designed shaft caps. The caps at each point where the arch ribs touch down are unique, created to perfectly match with the ribs and the bridge's vertical supports. At the single touch point in the middle of the Willamette River, building the shaft cap was exceptionally challenging. This point will support not only the north- and southbound arch ribs, but also two vertical pillars. This center shaft cap is 8 feet wide, 12 feet tall and 6 feet thick. It is shown here with rebar cages coming out of the top to frame the vertical supports and the arch rib connection points sprouting from its sides.

While one part of the team dug deep below the river, another was busy building a frame high above the work bridge to the support for the falsework that would shape the reinforced concrete arches. During construction, this frame will provide critical support to both the arch and the crews working on its construction.

Next time: framing the arches and building the skeleton.