Simulation of the response of ancient columns under harmonic and earthquake excitations

In this paper, the seismic behavior of ancient monumental structures with monolithic or multi-drum classical columns is investigated. In particular, the Discrete Element Methods (DEM) are utilized in the study of ancient columns under strong ground excitations, by simulating the individual rock blocks as distinct bodies. A specialized software application has been developed, using modern object-oriented technologies and computer graphics. A large number of parametric studies has been performed in order to investigate the effect of certain parameters on the response of multi-drum columns. Specifically, the influence of the peak ground acceleration and the excitation frequency under harmonic excitations is examined, using small-scale experiments and numerical simulations. The value of the peak ground acceleration that is needed to initiate either sliding or rocking of multi-drum columns was found to decrease with the increase of the frequency of a harmonic excitation. Conversely, the simulations indicate that multi-drum columns are significantly more vulnerable to collapse at low-frequency excitations, which do not commonly occur in the Eastern Mediterranean region where most of these monuments can be found.