Beauty that carries the load

Leslie McManus

Challenge

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

Solution

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

Delivery

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.

Recommended products and insights

How to build a bridge that saves a fortune

Our expert Andy Backhouse explains how the right grade of stainless steel can create a structure that resists corrosion and minimizes maintenance needs over a typical bridge lifetime.

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.

Forta

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).

Sustainability

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

Article

What if bridges were built to last?

Case pedestrian bridge

Spanning time and distance

Article

Home of Rioja wine toasts sustainable stainless steel footbridge

Case Pedestrian Bridge at TRUMPF Headquarters

Footbridge safely connects TRUMPF employees

Case Stockholm railway bridge

Upgrading bridge construction

Case Södertälje bridge

Designed to last

Case Story

The ultimate cliffhanger - The Gap

Article

Duplex in bridges and structures

Article

Sustainability is driving the adoption of duplex steel