Description
The prevention of progressive collapse of buildings due to abnormal actions has gained interest in recent years. In Reinforced Concrete (RC) frames, strong settlements of one or more columns, caused e.g., by design or construction errors, underground works or foundation failure, can be considered as an example of such abnormal actions. Downward displacement of a limited number of structural elements should not result in disproportionate collapse of the whole structural system or a major portion of it, especially in case of public buildings. Therefore, it is important to establish damage limit states for such indirect actions, which can be used to assess the reliability level of existing structures, as well as to proper design Structural Health Monitoring (SHM) systems. Recent research shows that the behaviour of RC buildings during accidental events can be predicted by means of Non-Linear Finite Element Analysis (NLFEA), which considers material and geometrical nonlinearity.
In the present study, NLFEA is used to examine the behaviour of an existing building with RC framed structural system subjected to column strong settlements. Firstly, the modelling methodology is validated against the outcomes of experimental tests from the literature concerning the progressive collapse of a planar RC frame with and without infill walls. Then, the behaviour of an existing Italian school building subjected to an evolutive movement triggered by column strong settlements or column removal is simulated by both considering and neglecting the presence of infill walls. Damage evolution in the structural elements is assessed with respect to performance limit state thresholds available in the literature. The proposed methodology can represent a useful tool for the assessment of building vulnerability against soil failures and can be extended in the future to different settlement scenarios.
