Seismic reliability assessment of classical columns subjected to near source ground motions

Abstract

Classical columns are articulated structures made of several discrete bulgy stone blocks (drums) put one on top of the other without mortar. Thanks to their unique structural system, many of these structures have survived several strong earthquakes over the centuries. However, many others have collapsed. The dynamic behaviour of these systems is rich, complex and very sensitive to the ground input motion. A performance-based seismic risk assessment methodology for the vulnerability assessment of multidrum columns is discussed and presented on two columns of different size. The first column was inspired by the Parthenon Pronaos and the second from the Propylaia of the Acropolis hill in Athens. The Discrete Element Method (DEM) is adopted in order to simulate the three-dimensional dynamic response of the columns. Limit-state exceedance probabilities are obtained using the Monte Carlo simulation and a series of synthetic ground motion records of varying magnitude and source distance. The results pinpoint the different vulnerability of the two columns and verify that larger columns are more stable compared to smaller with dimensions of the same aspect ratio. The methodology presented may serve as a valuable decision-making tool for the restoration of classical monuments.