New pedestrian bridge now open over I-17

By Kimberly Noetzel
ADOT Public Education Manager

The Phoenix-area's newest pedestrian bridge is in place over Interstate 17 just north of Happy Valley Road.

ADOT installed the 160-ton, 600-foot long bridge over two nights in June next to the Central Arizona Project (CAP) canal.

Working in partnership with the CAP, city of Phoenix and Federal Highway Administration, ADOT designed and built this bridge to provide long-term connectivity for the CAP's multi-use recreational trail. Because the city of Phoenix will maintain the bridge, ADOT designed it to require only minimal maintenance after installation.

When you drive under or walk over the bridge, you might wonder why a new structure looks so … weathered. The answer? Weathering steel. Crews used weathering steel which, by design, gives outdoor structures a rustic appearance. Better yet, it never needs to be painted, which significantly reduces maintenance costs.

Weathering steel has what’s known as a "sacrificial surface." This means it rusts only on the outside. The base metal (structural component) does not rust. If you hail from the eastern United States, you might know that some big, old steel bridges need to be replaced over time because they rust all the way through and weaken...

But, with weathering steel, the load-bearing capacity and long-term durability of a bridge or other structure are not compromised.

In the Metro-Phoenix climate, the weathering process usually takes about six months and a couple of good rains. But for this project, we’ll let you in on a little secret: to jump start the weathering process crews sandblasted the steel and hosed it down prior to installation, making our new bridge look older than it really is to complement the natural environment.

The bridge, which is accessible from the CAP trail, is now open.