Degradations analysis and prediction methods of the mechanical behavior of masonry structures in the archaeological site Volubilis (Morocco)

Abstract

The archaeological site of Volubilis is located in Morocco, 60 km from the city of Fez. It is one of the most preserved sites of a large Roman city registered in the UNESCO world heritage list. This site is composed of several historical monuments, most of which are built in masonry. These structures are composed of blocks of stones bound or not with mortar. These components have different physical and mechanical characteristics, which makes understanding the mechanical behavior, mainly the mode of failure and damage and the bearing capacity of these structures, a complex task due to their anisotropic, heterogeneous, and composite nature. The constructions built on the site Volubilis have experienced deterioration and intense degradation over time, affecting their structures due to several factors. This makes the protection and conservation of these structures paramount. The present study aims firstly to classify the types of degradations observed at the level of the existing masonry structures in the Volubilis site by giving explanations, interpretations as well as the causes of these degradations; secondly, to explain the various analytical, empirical and numerical approaches usually adopted to predict the mechanical behavior of these masonry structures affected by degradations and more precisely their modes of failure, their zones of weakness as well as their bearing capacities. The analytical and empirical approaches presented in the literature only allow us to estimate the compressive strength of these masonry structures, which have a specific geometry. In contrast, the numerical approaches will enable us to highlight the causes of degradation and predict the modes of failure and damage of these masonry structures. Three modeling techniques are used in the numerical approach: detailed micromodeling (DMM), simplified micromodeling (SMM), and Macromodeling (MM), based on the finite element method (FEM). These techniques differ from each other in their degree of accuracy.