The buildings analyzed, namely Mallorca cathedral in the island of Mallorca and the church of Santa Maria del Mar in Barcelona, show common architectural features but also significant dissimilarities which, in turn, have lead to different damage and deformation conditions. As will be later described, one of the main differences is found in the construction processes and their consequences for the latter condition of the structure.
The studies were undertaken in close cooperation between historians, structural engineers, mineralogists, architects, geophysicists and other specialists. Detailed research on available historic documents has permitted the identification of essential issues related to the construction process and later events (architectural alterations, earthquakes, fires) having left their imprint on the structure. Geophysics, carried out by means of seismic tomography, pulse radar and dynamic testing, has been very useful in characterizing essential structural and morphological features. Structural analysis, carried out by means of classical approaches (limit analysis) and advanced non-linear numerical models, has permitted the characterization of the structural performance under gravity, soil settlements and earthquake (Clemente, 2007, Martínez, 2008).
Based on the information provided by historical and geophysical research, a sequential analysis has been developed, in the case of Mallorca cathedral, as an attempt to simulate some aspects of the construction process.
An essential issue of the diagnosis lays in the distinction of damage related to active phenomena, still contributing to further deterioration, from that which has resulted from past or already extinguished actions. In some cases, stabilized damage or alterations caused by past actions may be preserved and respected as a sign of identity linked to the historical character of the building. In other cases, repairing this type of damage may be necessary to avoid problems related to durability or functionality, or to improve the capacity of the building under extraordinary actions (as earthquake). If repaired, historical or traditional techniques should be preferred to alternative possibilities in order to avoid unnecessary loss of authenticity of materials and structure.
For obvious reasons, the ISCARSAH Recommendations (2005), state that the intervention must always address the real causes rather than "the symptoms". When addressing past or extinguished actions, the need for intervention should be carefully appraised and repair and strengthening should be limited to truly indispensable operations.
Possible historical actions which may have contributed to damage, but (in principle) are not expected to happen again, include anthropogenic ones (wars, fires and other types of destruction, lack of maintenance and inadequate restorations) and natural ones (as stabilized soil settlements). Earthquake does not lay in this group for obvious reasons. Yet another "action" belonging to this group, which by no means should be neglected, is the construction process itself and its related hazards and difficulties.
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