Lessons from past explosive tests on protective structures in Japan

This paper introduces three experimental research works on protective structures against bomb and blast loadings that were directed by the late Professor A. Johoji, who was then a Colonel in the Fortification Headquarters of the old Japanese Army before WWII. First, bombing tests for reinforced concrete (RC) buildings were performed in order to examine the effects of reinforcement of the roof against aerial bomb attack. Second, blast loading tests for RC wall shelters were carried out in order to investigate the effects of concrete depth and size of an RC wall against blast loading. Third, explosive tests for various types of tunnel shelters were conducted to determine the effects upon corners in branch type and mesh type tunnels under blast pressure.