This report is part of the Infravation research project “Fast and effective solution for steel bridges life-time extension”. Within Work Package 4 “Strengthening system process qualification”, the adopted strengthening system for Jarama Bridge in Madrid, Spain, is to be validated by means of a well-defined experimental campaign regarding static, dynamic, application and durability topics of the assembly. This report covers the result of task 4.6 “Fine-tuning and formulation of the methodology: assessment, design, application and maintenance guideline”. In the scope of Work Package 4 it is the fourth delivery. This report seeks to fine-tune the methodology with inputs of Work Package 2 and the tasks 4.1 to 4.4. Doing this, a guideline will be developed, explaining the proposed methodology. This guideline will be simple and user friendly in order to reach a considerable amount of users.