PSI - Issue 78

Fabio Micozzi et al. / Procedia Structural Integrity 78 (2026) 1205–1212

1208

Fig. 3. Faults, locations of epicentres and faulting mechanism of the two main earthquakes, field surveys of the fault made by the reconnaissance mission, position of the cases reported in this paper. 2. Expected effect on the structures crossed by the fault. The earthquake was generated by a left-lateral strike-slip fault (standing on one side of the fault and looking across it, the block on the other side has moved to the left). Any structure partially intersected by the surface rupture may undergo a counterclockwise rotational distortion when observed in plan view, as shown in Fig. 4. The resulting differential displacement may introduce torsional effects and shear stresses into the structural system, often leading to complex damage patterns related to the specific position and orientation of the fault respect the structure axes and, in some cases, structural failure. However, in the context of a strike-slip fault, compact structures with foundation that are both rigid and shallow may survive if the structure is able to slide on the ground: if the foundation resistance is higher than the sliding forces induced by the fault movement and the stiffness foundation is enough to avoid significant deformation the fault movement result in a simple rigid rotation of the structure. In such cases, once friction has been overcome by the fault’s relative movement, the structure may behave somehow like a “seismically isolated system”. Consequently, during sliding, dynamic actions can be significantly reduced and the structure is subjected to lower inertial forces compared to adjacent, more rigidly anchored buildings.

Structure

Fig. 4. Rigid rotation and shear deformation of a structure intersected by a strike-slip fault.