Forensic analysis of a RC building collapsed during the 1998 Sarno Landslides

On May 5th and 6th, 1998, hundreds of flow-type landslides were triggered in the “Pizzo D'Alvano” relief, causing more than 100 deaths and huge damage to the built environment. This study evaluates the vulnerability of reinforced concrete (RC) structures to landslide impact. A detailed back-analysis was conducted on a five-storey reinforced concrete building that collapsed during the event. This analysis established probable impact velocities that led to the structure's collapse and identified the initial failure mode. The building characteristics were defined through a simulated design procedure based on the codes in force at the time of construction. Nonlinear static analyses, implemented through fibre-based distributed plasticity models in OpenSees, were used to assess load-bearing capacity at both global and local scales. Sensitivity analyses under varying flow velocity, impact angle, flow depth, and column-to-wall connection further clarified the collapse mechanisms.