Mechanically consistent scaling of historical stone columns

A number of sites inscribed on the World Heritage list have sustained damage to their stone columns as a result of seismic events that have occurred over a period of thousands of years. Despite the acknowledged risk posed by seismic activity to such structures, there remains a paucity of scientific knowledge concerning the behaviour of stone block structures under seismic loading. The present study focused on the rocking motion between two stone drums, besides the sliding and torsion motions. This mechanism is the primary driver of seismic behaviour in large multi-drum stone block columns, exemplified by those observed in the Neptune Temple. The contact mechanism was modelled at the local level using tribology. In order to develop a realistic global model for such structures, a connection was established between the local and global behaviour by applying Mechanically Consistent Scaling (MCS). Consequently, the global structural analysis incorporates local information, thereby facilitating the generation of more detailed results. The local numerical model was developed using the finite element method with the Abaqus software. The model takes into account the non-linear characteristics of the local contact between the two stone drums, including behaviours such as stick-slip and overclosure-clearance. Subsequently, MCS furnished the constitutive relationship for a macro element that connects individual nodes situated at the centres of consecutive stone drums. The utilisation of only six degrees of freedom (DOF) at each drum enables the efficient modelling of complete columns, drum by drum, without the loss of information at the local or global scale. Local behaviour can be retrieved at any time-step during a time history analysis. To verify the developed local and macro models, a series of small-scale tests and hybrid simulations using a 1:3 scale model column of the Neptune Temple were conducted. The developed local model can now be applied with confidence for the seismic analysis of other Greek column structures that have survived through many earthquakes.