Back-analysis sheds light on the history of the Acropolis Wall: The interpretation of a permanent structural failure

摘要

This work describes a back-analysis for the interpretation of a serious structural failure observed in an area of the Acropolis North Circuit Wall. The failure occurred, according to the available historical and archaeological evidence, at the end of the 18th or beginning of the 19th century and it includes a) the collapse of the upper part of the Wall in the area examined (the crown of the Wall that had been constructed of architectural members of the entablature of the Old Temple of Athena), b) significant outward lean from the vertical (7 cm) of the remaining lower part (the part beneath the crown that collapsed), c) rotation of approximately lo d) systematic cracking of the outward face of the wall. For the analysis, the principles of rock mechanics were applied for simulation of the dry-masonry construction. Since the damage was primarily attributed to a strong earthquake motion, for the problem description information is drawn from a wide range of scientific specialization. The analyses comprised: 2-D FE elas-toplastic analysis, simplified (pseudostatic) spectral dynamic analysis and a rigorous 2-D time history analysis. The results are proven very satisfactory. The permanent displacement of the current crown of the wall, the rotation of the structure, the collapse of the entablature members (form T) and the systematic net of fractures at the outward side of the wall are consistently predicted. Therefore, the assumption that the damage was caused by an earthquake was also verified, limiting the termini of the event between 1785 and 1805.