The increasing tendency to use urban civilian buildings for military purposes prompts the need for the assessment of their blast resistance. Many of these buildings are made of reinforced concrete (RC). Popular tools available for the assessment of existing RC structures in practice include guidelines and design standards, technical manuals and specialised software. These tools include certain assumptions based on scarcely available test data, as historically they were collected for military purposes. Efforts to transfer this knowledge from military to civilian applications are relatively recent and need be corroborated by further testing and numerical analysis. The objective of this paper is to present the results of field tests on full-scale RC members to check the validity of a number of assumptions routinely made in current numerical/analytical models. The data captured during the tests, including reflected pressure and member displacements, are compared with results of empirical and numerical models, in order to gauge the robustness and accuracy of the assumptions underpinning these models. Finally, recommendations are made for an expedient assessment of existing buildings based on simple methodologies.