The wire mesh panels that line the sides of this pedestrian bridge, named Gideon Overcrossing, play a key role in the design of the award-winning walkway in Portland, Oregon. Spanning across the TriMet light rail and Union Pacific Railroad heavy lines, the elevated passage relieves crossing wait times that previously could exceed a half-hour, often resulting in pedestrians and bicycle riders climbing between rail cars to cross. Architects at DAO Architecture, LLC, working with fabricators at A2 Fabrication, utilized Banker’s pattern LZ-185 in weathering steel to create an enclosure that is durable, safe, and long-lasting.
The wire mesh pedestrian bridge portion of Gideon Overcrossing stretches across the tracks at 12 feet wide and 140 feet long, with 8-foot tall walls. Flanking both sides of the bridge are concrete staircases and bike channels as well as steel and glass elevator towers. The structure is primarily constructed from weathering steel, including wide flanges, corrugated siding, and Banker’s wire mesh. LZ-185 covers the full 8-foot height of the wall from one end of the bridge to the other, as well as the barriers along the stairs.
“Gideon Overcrossing is public infrastructure, so needed to be extremely durable and low-maintenance,” states Joann Dao Le, principal at DAO “Weathering steel was used for its aesthetic qualities, as well as it being virtually maintenance-free and not requiring any additional painting or finishing. The material, weathering steel, and mesh pattern reinforced the refined industrial nature and aesthetic that we were looking for with the bridge.”
The vertically oriented rectangular openings of LZ-185 create a sturdy and reliable barrier surrounding Gideon Overcrossing. The small openings prevent objects from being thrown or falling onto the tracks. They also offer a consistent barrier that protects from fall risks across the 26-foot high bridge. Benefitting from the use of wire mesh over other solid materials like glass or metal panels, the pedestrians making use of the crossing enjoy abundant natural light, ventilation, and an unhindered view of the Portland skyline.
The choice of weathering steel comes from a variety of factors, the most prevalent being durability and maintenance. The mesh pictured here has nearly completely developed its patina over the course of a year, creating a protective layer that will defend the structure against corrosion and heavy wear and tear. The unique orange and brown tones of the wire mesh complete the visual aesthetic of Gideon Overcrossing, contributing to DAO’s win of the 2021 Engineering News Record NW Best Small Project award and finalist placement for the 2021 DJC-Oregon Top Projects Award.