Proposals for the Military Load Capacity Assessment of Existing Road Bridges

The STANAG 2021 agreement, which is used by NATO member states, defines the standards for the military capacity assessment of road bridges. The standard allows bridges to be classified into 16 classes. The standard does not give a fixed value for the factors for the load capacity classification, but each member country can determine these in the light of their national bridge design codes. The present study summarises the proposals for the inclusion of certain factors (safety factor, dynamic factor) for the classification of existing bridges in Hungary. This summary also includes a proposal for modifications to the magnitude of civil loads travelling parallel to military loads. With these factors, many trial calculations were made for each group of existing Hungarian road bridges. Out of the hundreds of sample calculations, some examples (for eight types of bridges) have been presented, including some with good load capacity and some with low load capacity. Based on the sample calculations, it can be determined for which types of bridges it is recommended to carry out further calculations to verify higher military capacity. For this, STANAG 2021 provides options assuming cautious and risk crossing conditions. The sample calculations also show where in the Hungarian bridge stock structures can be found that may be inadequate for military mobility. Our research is also an example of civilian and military cooperation, which is essential for the load classification of existing road bridges.