Serviceability and damage scenario in RC irregular structures: post-earthquake observations and modelling predictions

The catastrophic earthquake that struck the city of L'Aquila in early April of 2009 caused extensive damages to University of L’Aquila buildings. Among these edifices those of the Engineering Faculty, in particular, suffered large structural displacements and accelerations that resulted in failures of non-structural elements (infills, false ceilings, door and window frames), the breakage of wiring and piping systems, and the destruction of furniture and machineries. Of these buildings, so-called “Edifice A” presents the most critical damage scenario, requiring a significant rehabilitating intervention. The structural behavior of this building, composed of seven independent RC substructures, is the object of intensive investigation, in part because irregularities among these substructures, in terms of geometry, stiffness and weight distribution, provide a rich case study for interpreting different structural and non-structural damage scenarios. The paper tends to interpret the observed damage through the use of incremental analyses for the evaluation of the threshold between linear and nonlinear structural behavior. For this purpose, several FE models are developed with increasing complexity in the geometry and in the shear wall modeling. The capacity curves obtained by the nonlinear pushover analyses are afterwards compared with the seismic demands perceived by the structures including site effects. Moreover, numerical evaluations of the acceleration producing failures in the infill walls and the split-face brick walls are made, based on simplified analyses, to achieve an overall description of the structural and non structural damage that occurred.