STRUCTURAL AND DURABILITY ASSESSMENT OF THE BRIDGES ACROSS THE LOW-RHINE (NL)

摘要

The road capacity on the bridges across the Low-Rhine will be increased in the near future. Because of the increased load the bridges were structurally assessed. Inspection revealed many diagonal cracks in the webs of the twin box girder near almost every pier. Based on an in depth-analysis a design for strengthening the bridges by external tendons was made. Due to corrosion of the drainage pipes the concrete around the pipes has been contaminated with chlorides from de-icing salts. In three spans the risk of corrosion of the original prestressing tendons has been assessed. High levels of chloride ingress have been found, leading to a significant risk of corrosion of the tendons of the edge beams. Although the strengthened bridge has sufficient resistance even when six post tensioning tendons are lost by corrosion, it is recommended to assess the risk of corrosion for the whole bridge and take remedial actions where necessary.