This article has been adapted from a series of Structural Stainless Steel case studies produced on behalf of Team Stainless by SCI and available for download from www.nickelinstitute.org -
March 20, 2014
Imposing and important, Stonecutters Bridge in Hong Kong provides a vital commercial link in an environmentally demanding setting. It also depends on nickel-containing stainless steel to ensure safe and continuous service over its 120 year design life to cope with salt water, industrial pollution and frequent typhoon events.
The most striking features of the bridge are the twin tapered mono towers at each end which rise to 295m above sea level and support the 50m wide deck. While the lower sections are reinforced concrete, the upper 115m are composite sections with an outer stainless steel skin and a reinforced concrete core.
Circular towers are known to be susceptible to vortex shedding vibration. To avoid it, the upper part of the tower was designed as a composite structure with a stainless steel skin around a reinforced concrete annular core enclosing the steel cable anchor boxes. Its greater mass, stiffness and damping gave the bridge an improved response to vortex shedding.
In addition, the height of the towers and the busy traffic beneath means that maintenance needs to be kept to a minimum. Nickel-containing stainless steel was chosen to clad the upper part of the tower because of its durability and attractive appearance. The alternative, carbon steel, would have required replacement after an estimated 25-30 years with repeated additional costs and disruption of traffic over the 120 year service life. Duplex stainless steel 2205 (S32205) was the material of choice, thanks to its high yield strength (460 MPa) and superior corrosion resistance.