ROSE School, IUSS Pavia, Italy
EUCENTRE, Pavia, Italy
Department of Structural Mechanics, University of Pavia, Italy
Earthquake Engineering Center, NWFP University of Engineering and Technology Peshawar, Pakistan


The paper presents the calibration of a displacement-based method, presented herein, for seismic vulnerability assessment of masonry building stock on regional scale. The method makes use of equivalent single degree of freedom (SDOF) systems to assess the seismic vulnerability of structures with due consideration of expected uncertainties in geometrical and mechanical properties of the structures besides the uncertainties in seismic demand. The SDOF system is defined completely by knowing the characteristic vibration period, limit states displacement capacity and the characteristic energy dissipation of the structure. Nonlinear dynamic time history analysis of 3D masonry building classes are performed using equivalent frame method to derive the equivalent SDOF systems of masonry buildings. The SDOF systems take into account the stiffness and strength degradation due to cyclic and in-cyclic response, higher mode effects and torsional response of the buildings. Furthermore, the available experimental data on masonry walls is obtained in order to define the limit state deformation capacity at different performance levels and the characteristic energy dissipation of masonry buildings. Simplified formulae are proposed for the aforementioned characteristic properties of masonry buildings.

Key words
Unreinforced masonry, vulnerability assessment, displacement-based, equivalent frame method