Development of a methodology for the optimized planning of retrofitting and/or replacement of important bridges

Many of the federal highways built before 1985 have a load-bearing capacity that is not sufficient to withstand the present or predicted freight traffic loads.

The subject of the predecessor projects "Retrofitting I and II" was the planning of necessary retrofitting and/or replacement measures on the bridges concerned. A prototype procedure for calculating optimised retrofit programmes to minimise the overall economic impact of the unavailability or limited usability of bridges in a subnetwork was developed. The methodology was applied to an example with Rhine crossings in NRW between Bonn and Duisburg. In the project, the method was further developed with the aim of applicability to larger sub-networks. The aim of the project was to develop a software prototype with which optimised retrofitting programmes can be calculated.

The task of the continuation project "Retrofitting III" is to transfer the developed methodology into practice. This is to take place within the framework of an initial application for a sub-network with approx. 50 bridges using the present prototype.

Method for the preselection of buildings

The procedure for the pre-selection of structures under constructional and macroeconomic aspects is intended to help building authorities to identify particularly critical structures at an early stage in order to include them in a procedure for planning measures at subnetwork level.

Methodology for the analysis of retrofitting options

With the new methodology the structural effects and the impacts on traffic and economy of different upgrading options can be assessed.

Methodology for setting up upgrading programmes for subnetworks

The upgrading programme is intended to generate the highest possible macroeconomic benefit for the selected subnetwork and to keep the user costs as low as possible.