Miles of steel create strong skeleton for new bridge

From ODOT-

Reinforcing steel, or rebar, is one of the most integral parts of a bridge even though you never see it.

Ironworkers from Manske Construction form and tie together miles of rebar cages, creating the strong skeleton for the piers that will support the new northbound I-5 bridge. Then, they install the steel framework into the drilled shafts before the concrete is poured to form piers, creating the part of the bridge that you do see.

The span of the rebar ranges from as small as 1/2 inch in diameter up to 2.25 inches. For this project, we use the largest diameter rebar available, which weighs 14 pounds a linear foot. The new southbound bridge contains 2.7 million pounds of rebar, the weight of more than 3 fully loaded jumbo jets at takeoff. The northbound bridge will contain a similar amount of reinforcing steel.



Ironworkers tie the steel rebar to form the pier cages in a work area in Alton Baker Park, just north of the Knickerbocker Bridge.

Ironworkers and welders build the steel structures by typing together miles of rebar.

A large crane lowers the tied rebar down into a shaft to form an abutment wall.

Here is how the rebar looks inside of the pier shaft, before the concrete is poured. The bridge pier shafts average about 35 feet deep below the riverbed.