Innovative reinforcement method
In principle, there are two reinforcement methods for steel bridges: the application of high-strength concrete or the installation of steel plates that are glued to the road surface with epoxy or in other words glue. However, high-strength concrete is too heavy for the relatively light Suurhoff Bridge. For this renovation, Rijkswaterstaat therefore chose to use reinforcing plates.
The Suurhoff Bridge, however, moves so much that epoxy alone would not be strong enough to allow the steel plates to adhere properly and permanently. Therefore, for the first time in the Netherlands, the plates on the Suurhoff Bridge are being reinforced with epoxy and steel bolts. This new combination method ensures that the steel plates are firmly attached and do not shift or deform.
Suitability test
The new approach was developed and tested in collaboration with engineering firms Arup and Royal Haskoning DHV and with the hiring combination Stipt, consisting of Hollandia, Dura Vermeer, Besix and Mobilis TBI. TNO and TU Delft also contributed to the study.
Last year we carried out a suitability test, including a load test in which a section of the carriageway of the Suurhoff Bridge was reconstructed on the Hollandia site with new reinforcement plates driven over by fully loaded trucks. Thanks to sensitive sensors on and under the plates, the researchers involved were able to study the effects and check the research models immediately. In all control stages, the epoxy in combination with bolts proved to perform better than expected and was therefore suitable for use on the Suurhoff Bridge.
Tough challenge
Rijkswaterstaat has a tough task ahead of it for the replacement and renovation of existing infrastructure. Many bridges and tunnels date from the 1950s and 1960s and are in need of major maintenance or replacement.