Serious deterioration of the concrete piers was detected only a few years after opening. Most of the piers were consequently reconstructed in 1980s and 1990s. The expansion joints and several kilometers of the concrete edge beams and railings were also replaced.

In 2004 the Owner required a minimal residual service life of at least 70 years. In order to fulfill this requirement a comprehensive technical and economic investigation has been carried out. This has resulted in an optimal maintenance strategy for the 70 year period. The investigation is based on data from earlier inspections and investigation as well as construction data, which was reviewed and evaluated.

All types of repair methods have been investigated and evaluated, ranging from well known traditional methods to recently developed modern methods.

Each structural element was first investigated separately, which resulted in one to three strategies per element. The individual element strategies were consequently further developed by combining them to one optimal overall strategy. This process was governed by the following main considerations:

• Minimization of traffic disruptions and expenses related to traffic arrangements and access equipment 
• Establishment of the most appropriate maintenance and/or repair methods 
• Well documented and durable repair methods, since the security and economic consequences are vital on a bridge of this size 
• The optimal points of time for execution, which secure a total minimum of expenses for the combined repair works.

An essential part of the overall strategy is the plan for further investigations, which will allow the strategy to be further tuned by giving a more accurate basis for the scope of the repairs as well determining the optimal time schedule.

The final report from the investigations includes:

• Structural assessment 
• Evaluation of condition 
• Traffic analysis 
• Strategy for the individual structural elements 
• Operation and maintenance strategy for the entire bridge (main strategy)