Steel decks are mainly used in bridges where concrete decks result in too much dead weight: in both decks for long fixed bridges and for movable bridges. In traffic bridges, steel decks are often built as welded orthotropic decks.

At the end of the last century it was found that many of the orthotropic steel bridge decks showed signs of fatigue due to the increase of traffic intensity in general and the use of super single wheels for trucks in particular. Orthotropic steel decks generally consist of a deck plate of 12 mm thickness at a minimum, and typically every 300 mm is supported by webs of bended \_/-shape steel plate ribs, which are welded underneath the deck plate.

Currently, the most applied solution to fatigue is an in-situ overlay with high strength concrete (HSC), replacing the asphalt layers. For decks with only a thin epoxy/grit wearing surface layer, this results in a heavier and higher deck, which is a considerable disadvantage when it comes to movable bridges.

As an alternative, an underlay of the steel deck plate consisting of a foam core and a glass-fiber reinforced polymer (GRP) bottom plate was studied, as a potential solution for obtaining the same weight and height. The hybrid sandwich replaces the \_/-ribs. The foam core creates a smooth uniform distributed support for the steel deck plate instead of the concentrated line supports.

This article appeared in the July–August 2019 issue of Reinforced Plastics. Log in to your free materialstoday.com profile to access the article.

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