Retrofit, Restoration and Preservation of Byzantine Monuments: Assessment of Natural Degradation and Evaluation of Intervention Options

Monuments reflect the depth and grandeur of a great civilization developed in a certain region, during a specific period of history. They possess aesthetic, historical and functional values. Undoubtedly, they are seen as part of mankind’s cultural heritage. In particular, the ecclesiastical byzantine monuments in countries where the byzantine civilization flourished, between the 4th and the 15th centuries, such as in Greece and Cyprus, are of great importance, because they are considered as edifices that offer, through their aesthetic and archeological study, a mental upgrade and valuable knowledge of roman and byzantine building techniques. Thus, the need for periodic maintenance and restoration of such monuments is imperative. The objective of the present work is to give a general description of the basic steps of the dominant retrofit methodology which is nowadays used in Greece and Cyprus and leads to the preservation of byzantine monuments. This method is the same as in any other type of monument and goes through four stages: (i) in-situ visual investigation of the degree of wear and on-site experiments, (ii) laboratory testing of the original materials of the monument under study, (iii) installation of a wireless sensor network on a monument under study, aiming at the most efficient monitoring of local displacements, differential foundation settlements, temperature changes, local humidity concentration, salt formation, etc. and (iv) evaluation of several retrofit options and the implementation of the optimal solution, by applying a formulated grading methodology. An immediate finding of the present work is that these steps enable the creation of a suitable analytical model which can be used in runnig a software package, for the design of a complete retrofit/restoration procedure and the preparation of accurate architectural and structural drawings, which will finally be used for the implementation of the maintenance/preservation design. Undeniably, what is important is to select the optimal retrofit procedure for this type of historical buildings, something which is explained in detail in this article. The latter statement expresses the scope of the present work. Another major finding of this review research is that the above retrofit procedure has already been applied to many byzantine monuments, during the past twenty years in Greece and in Cyprus and seems to have already become the dominant method over existing practices, because it uses modern technologies and is more efficient and effective, since it is based on optimization procedures.