A new design for steel bridge decks using laser fabrication


Steel orthotropic decks provide a lightweight form of construction, essential for weight-critical structures. However, their cost and poor record of fatigue durability has discouraged their use for mainstream construction. As a result, steel decks are generally considered an option of last resort, only used where the minimisation of self-weight is essential, such as long-span and moveable bridges. An innovation is proposed to overcome these problems and transform the design of steel decks. The innovation is based upon the use of laser welding to produce an enclosed 'sandwich panel' profile. The sandwich profile shown below overcomes many of the constraints to structural performance associated with the use of conventional orthotropic steel decks. As well as enhancing the global structural characteristics of the deck, fatigue durability is further enhanced by the laser welding process used to fabricate the panels. An extensive range of fatigue tests are presented on the welds used to join the panels. A jointing arrangement is described which offers outstanding fatigue strength and exceptional economy in assembly and fabrication. Laser welds are extremely cheap to produce and the use of proprietary rolled sections offers significant savings inconstruction costs compared to conventional steel deck designs. The sandwich design has the potential to provide a , competitive, lightweight alternative to the concrete decks used in general bridgeworks. Proprietary sandwich panels may also be an attractive proposition for deck replacement schemes where the introduction of a lightweight deck could facilitate an increase in the live load capacity of understrength bridges. Further testing of a complete deck assembly is required to exploit the future potential of the system.

Publication Title

Structural Engineer

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