Beauty that carries the load

Leslie McManus


A landmark pedestrian bridge posed unique needs: a primary structural material that could deliver both enormous strength and longevity in a marine environment.


Forta, Outokumpu’s high-strength duplex stainless steel, was the designers’ recommendation for uncommon strength and exceptional corrosion resistance.


Steel grade: Outokumpu Forta DX 2205

Opened in 2011, the Harbor Drive Pedestrian Bridge spans 168 meters, giving pedestrians safe passage over a busy thoroughfare, rail yard and trolley tracks. Part of the 3.2-kilometer Park-to-Bay Link, the bridge symbolizes San Diego’s nautical heritage while serving as the new southern gateway to the downtown area.

The graceful, single-cable self-anchored suspension bridge features a 40-meter pylon inclined at a dramatic, 60-degree angle over the bridge deck, which is suspended over just one side. The bridge’s streamlined design is a departure from the bulky suspender and main cables typical of traditional suspension bridges. Here, smooth, uninterrupted lines created by innovative design completely hide the large main cable.


Unique structural requirements

Designed by Safdie Rabines Architects, the Harbor Drive Bridge has a uniquely transparent profile. A 6-meter-wide deck is supported by 34 individual suspenders attached to the main cable.

The main cable, which is carried in a stainless steel welded pipe fabricated from Outokumpu plate, supports the bridge deck via tension cables through the pipe and heavy plate railing posts. The railing posts do double duty, alternately supporting the concrete deck and transferring radial force from the top of the railing to the deck.

Structural engineers T.Y. Lin International chose Outokumpu’s exceptionally strong duplex stainless steel, Forta DX 2205, for the custom-fabricated posts and the welded pipe.


Designed for sustainability

Corrosion resistance is essential for a bridge in a marine environment, particularly one marked by regular salt fog and infrequent heavy rain. Acknowledging its superior properties, the project’s designers chose stainless steel rather than painted steel, gaining long life with minimal maintenance.

For pedestrians, the Harbor Drive Bridge offers a unique opportunity to experience timeless design. The use of stainless steel as both a primary structural material and one delivering enduring beauty makes this an iconic landmark.

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Stainless steel for bridges

Bridge projects are in a class of their own – just like Outokumpu stainless steel. Marked by harsh environments, heavy lifetime usage and high aesthetic expectations, bridges demand special considerations upfront if they’re to go the distance.


The Forta range contains duplex and other high strength stainless steels that enable thinner structures and weight reduction (measured in Rp0.2 > 400 MPa. PRE 16 to 43).


Stainless steel is a superb material for sustainable solutions as it is 100% recyclable, efficient and long-lasting. Our vision is to become the customers’ first choice in sustainable stainless steel.

Recommended reading

Global megatrends article

Taking the sustainable path towards building bridges that endure and inspire


Materials in bridges: a designer’s perspective


Design standards and sustainability in structural engineering


Welding of stainless steel bridges


New opportunities with modular bridges


Sustainability is driving the adoption of duplex steel

Case Sodertalje bridge

Bridging the way to a more sustainable and economical future


The future belongs to sustainable bridges


Economic drivers for selecting stainless steel