Behind the orange cones: the skeleton of the bridge

From ODOT-

In our latest video, crews tie together miles of rebar to form the intricate web of steel reinforcing bars that is the unseen skeleton of the entire bridge. The rebar ranges from as small as one-half inch in diameter up to 2 1/4 inches across.



For this project, we use the largest diameter rebar available, which weighs 14 pounds per linear foot. These big steel bars are so heavy that it takes several steelworkers to move them into place and tie them into the reinforcing framework that supports the bridge piers and arches.



It’s fascinating to see up-close the cages that will become the concrete columns supporting the bridge. I interviewed ODOT Quality/Quantity Coordinator Thor Alvarado about the training and experience needed to work with this heavy and intricate material.



Thor’s job is to inspect bridges under construction throughout the state. His experience is valuable on a complicated project like ours because he makes sure bridges are built properly, safely and within budget.



According to Thor, the biggest challenges of working with rebar are harsh weather and lifting the long and heavy steel bars into place. He says teamwork is important because it’s dangerous work.



Do you know what happens to the rebar if steelworkers try to bend it with a torch? Watch the video to find out!



And feel free to post your comments and questions. Your feedback is important to us.

I-5 Canoe Canal Bridges near completion

From ODOT-

Crews with Slayden Construction Group are almost finished with the new northbound Canoe Canal Bridge. Now that the bridge deck is poured, the focus turns to installing railing and finishing the roadway.

Crews install wood forms between the bridge beams. The ironworkers use the rebar embedded in the beams (shown in the foreground) to secure interwoven rebar which will be surrounded by concrete when the deck is poured.

To pour the deck, the contractor installs steel rails on either side of the roadway to guide the concrete spreading machine. In addition, string lines control the paver direction and surface elevation. As concrete is delivered to the site, the paving machine spreads and vibrates the concrete evenly across the surface. Workers follow with hand tools to finish the deck surface.

Steel railing supports and guides the concrete paver along with an electric eye that follows the string line.

The deck then cures for up to two weeks to achieve the required hardness. When the railing and roadways are complete, the bridge will be ready for freeway traffic.

The finished deck awaits striping and other finishing touches.

A lot of concrete, rebar and other materials

From ODOT- Have you ever wondered about the amount of material it takes to construct a new bridge, especially one as large as the new southbound Willamette River Bridge?

Visitors on the project tours often ask this question. Here’s the answer.

The finished portion of the bridge will be made up of 2.7 million pounds of rebar and 7,300 cubic yards of concrete. Rebar is used to add tensile strength to concrete. It is usually made of carbon steel, and has ridges for better anchoring into the concrete.

The rebar ranges from as small as 1/2 inch in diameter up to 2.25 inches. It is labor intensive to install and link all that rebar together before the concrete can be poured.

More steel and a lot of wood was needed to build the work bridge in the river and the supports and wooden falsework where the rebar is installed and concrete poured to build the new bridge. About 14 million pounds of steel was used to drive the piles supporting the work bridge and to support the wooden falsework use to form the bridge arches. The amount of wood used on the work bridge and falsework exceeds 2 million board feet and includes 2-by-4’s, 8-by-8’s and many sheets of plywood.

The crew building the bridge used these materials to create the arches you now see spanning the river and the bridge supports and beams south of Franklin Boulevard.

On a side note, the web cam is operational again, check it out.