Finite element analysis of the seismic response of ancient columns

Abstract

Summary This paper presents a numerical study of the response to earthquake actions of eight ancient Greek multidrum columns, which were chosen as representative of a broad spectrum of the ancient columns preserved to date. The study was conducted using the FE software Abaqus, in three steps. At first, the software efficiency to predict the rocking response of dry‐stone structures was verified. Afterwards, various numerical models of one typical ancient multidrum column were seismically excited. Records of four real earthquakes differing in frequency content were used for the excitation of the models. Each column model was different from the others at least in one geometric or modeling parameter. Although the examined parameters affected the numerical results, their variation did not alter significantly the overall behavior of the column. In the last step of the study, numerical models of eight columns were seismically excited using four seismic records. In these analyses, among the simulation approaches tested in the second step, the simpler one was adopted. On the basis of the numerical results, conclusions were drawn regarding the seismic resistance of the columns and its correlation with the dynamic characteristics of the columns (size, slenderness, and frequency parameter) and with the basic intensity measures and frequency content indicator of the seismic motions (PHA, PHV, PHD, and Tg). Thus, criteria of seismic collapse for the multidrum columns are proposed, which can be used for the approximate assessment of the seismic vulnerability of free‐standing ancient columns, provided that the columns are in good preservation state.

Multidrum Stone Columns at the Pompeii Archaeological Site: Analysis of Geometrical Properties and State of Preservation

“…Nowadays, many ancients columns are free-standing elements with low or zero axial load, due to missing entablature and roofs [4]. Moreover, material decay, due to the time and natural or anthropic phenomena, foundation failures, presence of cracks, missing or misplaced parts, compromise their stability and seismic capacity.…”

“…The study of the seismic behavior of ancient Greek and Roman columns is of particular interest due to the significant seismic activity of the Eastern Mediterranean area [4]. Such studies were typically developed in technical literature according to three main approaches: (i) analytical [3,[5][6][7][8], (ii) numerical, with the use of a software [2,4,[9][10][11][12][13][14][15][16][17][18][19], or (iii) experimental [20,21]. The dynamic behavior of a multidrum free-standing column is controlled by rocking, sliding or a combination of the two mechanisms of the single drums or groups of them.…”

“…This seismic response is complex and highly non-linear [2,4]. Therefore, theoretical approaches initially involved analytical studies based on simplifying assumptions following the landmark study of G. W. Housner [5] and considered single and multiple block structures [3,[5][6][7][8]; then, recent studies were mainly developed with numerical methods [2,4,[9][10][11][12][13][14][15][16][17][18][19]. These studies found that the seismic response of such elements is sensitive to the geometrical parameters of the columns, as well as to the material elastic properties, the coefficient of friction and the amplitude and frequency of the seismic action.…”

“…It was found that when keeping the other factors constant when increasing the slenderness, the probability of collapse increased; conversely, when the size of the column was increased, the probability decreased. Likewise, Papadopoulos et al, from the Finite Element Method (FEM) analysis, derived criteria for the seismic stability of ancient free-standing multidrum columns in which, for a given seismic input, lager columns were more stable than smaller ones with the same aspect ratio [4].…”

“…The number of drums was found to be another important parameter affecting the seismic response of a column in terms of sliding and energy dissipation due to friction [4,13]. The influence of this parameter depends on the frequency of the seismic action [11].…”