Innovative orthotropic deck strengthening design for the Suurhoff lifting bridge

From 2018, a significant amount of deck plate cracks have been discovered on the movable part of the Suurhoff bridge. These cracks reduce the strength of the bridge and might lead to unplanned hindrance and costly repairs. Renovation of the ortho‐tropic steel deck was chosen instead of frequent inspections and repairs or replacing the structure from a risk and cost perspective.

The innovative strengthening scheme consists of the addition of a steel plate which is connected to the top of the existing deck plate by a combination of preloaded‐injection bolts and epoxy. The strengthening steel plate reduces the stress in the existing deck plate thereby improving the fatigue performance. The new and old steel work compositely due to the combined effect of bolts and epoxy resulting in a relatively light‐weight strengthening scheme. The design followed a risk‐based approach in which Arup closely collaborated with Rijkswaterstaat, contractors and research institutions to finish the full design and implementation in less than a year. The design objective is to provide at least 15 years additional fatigue life for the existing deck.

The design was developed with the help of a combined numerical and experimental campaign. The novelty of the strengthening scheme and the use of different materials required experimental validation on small and large scale. The extensive validation resulted in sufficient confidence for the Rijkswaterstaat to implement this innovative scheme on an important bridge in The Netherlands. This scheme is especially beneficial from a weight and construction time perspective and therefore suitable for further implementation on other bridges.