PSI - Issue 47

A. Vrouva et al. / Procedia Structural Integrity 47 (2023) 521–534 Vrouva et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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5. Conclusions During the restoration works on the Parthenon’s west pediment a rose the need for redesigning the pediment ’ s connections. In an effort to determinate the seismic forces induced to the connectors a systematic analysis of the construction was carried out, using the DEM method, utilizing the results obtained by the installed on site accelerographic array, thus determining the damping parameters for the analysis. The results of the analysis apart from providing the induced forces to the connections showed that: a) The connections were crucial for the stability of the west façade of the pediment, called orthostate, under seismic loading. b) The freestanding orthostate preformed a rocking motion around its base while -for the same scenario- the backing wall tend to slowly slide towards the east. c) The connection of the two facades of the pediment minimized the drifts on both facades and imposed a conformed and restricted rocking motion. The design of the connectors had to comply with determined design forces that prompted from the analysis and the preservation state of the marble blocks to be connected. Moreover the design aimed to safeguard as much archaeological information intact from the initial construction. An initial design that adapted to the aforementioned requirements was planned out and tested in situ. The tests aimed to ensure that final design would suffice to bear the intended design loads. From the tests the following are concluded: a) The design of well fitted L-shaped unthreaded titanium rods inside marble in drilled holes in total absence of mortars cannot bear pull out forces according to the tita nium rod’s capacity (up to 9 tons). The system fails with slipping of the rods at approximately 2tons. b) The design of anchored with cement mortar L-shaped threaded titanium rods inside marble in drilled holes can bear pull out forces according to the titan ium rod’s capacity (up to 9 tons). c) Two types of threading were tested for the anchorage, typical and low, and both behaved equally acceptable. d) The special design of the anchors for the backing wall with the generic form of a barrel anchorage with wedges proved sufficient for bearing the intended loads and all specimens failed with breaking of the titanium rod. Though the design comported in an acceptable mode it was decided that a simple anchorage with a double nut would suffice for that part. e) The complete connector with the anchored L-shaped rod in the marble joined with the special nut and the part anchored to the backing wall was tested proving the anchorage system can be trusted since only the intended part was systematically failing within the desired design loads of about 8,5 tons. Acknowledgements The authors would like to thank the Acropolis Restoration Committee for the fruitful discussions on the subject and especially Professor M. Korres and Professor P. Koufopoulos for their valuable insights. Also the Acropolis Restoration Service and especially the Director, Architect, V. Eleftheriou that encouraged and supported the project. The Supervisor of the Parthenon’s Restoration Technical Office, Architect, R. Christodoloulopoulou for the assistance to organize the experiments on the working site, and of course the personnel of the Service that materialized the specimens and took part in the experimental procedure, namely the Chief of Technical Stuff Sp. Kardamis, and the marble workers and technicians V. Velonas, D. Paparidis and G. Skalkotos, G. Koloniaris, N. Vailakakis, S. Hatzilias, M. Gasparis, M. Mentis, G. Kayiorgis, D. Kostas, E. Ntoga. Special thanks are owed to Dr. Civil Engineer E. Pasiou who helped throughout the experimental procedures and supervised part of the experiments, and the Architects of the Parthenon’s Restoration Technical Office Dr. V. Manidaki and K. Skaris for the many productive discussions. Special mention is intended for the Head and personnel of the Laboratory for Earthquake Engineering, of the NTUA’s School of Civil Engineering , without the support of whom this project couldn’t have been realized. The Laboratory apart from the personnel S. Asimakopoulos provided the loading devices and measurement instruments and of course the expertise in the field of testing. Mechanical engineer G. Parcharides, as an external partner, was responsible for the formation of all the special titanium parts used and tested in the experiments.