Numerical investigation of the structural role of vertical connectors between drums in ancient columns

The present paper is part of a research program, aiming to investigate the effect of vertical connectors (gomfoi) on the seismic behaviour of columns and colonnades, in ancient Monuments. The columns in ancient Monuments are constructed following the dry construction system, i.e., large dimensions structural members (marble or porous stones, depending on the importance of the monument and the availability of materials at the vicinity of the construction site) are positioned without mortar. Since the Classical Era, connectors are used for the better connection of the consecutive drums. The system of “poloiempolia”, which are of cylindrical shape, positioned in the centre of the drum, is in many cases replaced, or co-esixts in the Hellenistic and Roman Era, by vertical connectors of orthogonal parallelepiped shape (gomfoi), positioned near the edges of the drums. The dimensions and the positions of the vertical connectors (gomfoi) in ancient columns have been documented, based on published work and in situ observation, in monuments in Greece. Among the investigated monuments, the Gymnasium in Ancient Messene has been chosen for further analytical and experimental investigation. Preliminary numerical modelling and analysis (under seismic actions) of single columns has been performed, using two different types of numerical modelling, namely a finite element and a discrete element program. The results of the different procedures are presented here and are commented upon. The columns are modelled without connectors, in order to study the effect of the number and the height of the drums in the behaviour of the columns. The original column, consisting of three drums and a capital, is modelled also with vertical connectors, and the structural role of the connectors is commented upon. The modelling of the columns leads to the selection of the exact geometry of the columns to be tested, the expected actions on the interfaces, the required characteristics of the seismic excitations to be imposed to them, etc. as well as to the adequate design of the specimens and the setup for the shaking table tests.