This paper reports damage to an RC school building, particularly severe shear failure to secondary flat walls, by the 2016 Kumamoto earthquake. The vibration characteristics of building were evaluated by micro-tremor observation. Additionally, the damage to the building was investigated through numerical simulations. A series of parametric analyses revealed that the amount of the secondary flat walls would affect the collapse mechanism. Ultimate deformability of the building decreased when a partial collapse mechanism was formed, which was well evaluated by an evaluation method proposed herein.
