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Structural Topology Optimization Suggests Improved Suspension Bridge Design

Seventy-five years after its creation, the Golden Gate Bridge's well-known, parabola-shaped cable design is up for revision.

Today's more realistic approach has revealed that new U-shaped cables might be redesigned to better handle tension and compression. That's the proposition that structural engineer 
Matthew Gilbert (University of Sheffield) put forth in Structural and Multidisciplinary Optimization (January 2010). The findings are a fine example of the mathematics of structural topology optimization.

Using a numerical optimization program, Gilbert and colleagues showed it's possible to reduce the amount of material in parabola-shaped cables by 0.3% if Hencky nets are used at their ends. The researchers have been working under the assumption that the well-know and simple parabolic-shaped cables represented the optimum bridge design until Gilbert realized that the only option was that the current wisdom was wrong.

Structural engineer Tomasz Lewiński (
Warsaw University of Technology) indicated that Hencky nets could be fashioned out of composite materials.

Science Now 

Start Date: 
Monday, February 15, 2010