Please wait a minute...

Frontiers of Structural and Civil Engineering

Front. Struct. Civ. Eng.    2019, Vol. 13 Issue (4) : 767-786     https://doi.org/10.1007/s11709-019-0515-9
REVIEW
Marble epistyles under shear: an experimental study of the role of “Relieving Space”
E. D. PASIOU1, I. STAVRAKAS2, D. TRIANTIS2, S. K. KOURKOULIS1()
1. Department of Mechanics, Laboratory of Testing and Materials, National Technical University of Athens, Athens 15773, Greece
2. Department of Electronics, Laboratory of Electrical Characterization of Materials and Electronic Devices, Technological Edu-cational Institution of Athens, Athens 12210, Greece
Download: PDF(9002 KB)   HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks
Abstract

The mechanical response of mutually interconnected epistyles is studied experimentally. The specimens are made of two marble blocks connected to each other with an “I”-shaped titanium connector placed in grooves sculptured on the blocks and covered with cementitious material. The specific way of connecting epistyles simulates the one used by scientists restoring the ancient “connections” of the epistyles of the Parthenon Temple. This “connection”, although designed to sustain mainly tensile loading, undertakes, also, shear load, in case of excitations imposing to the epistyles displacements normal to the connector’s axis. Attention is focused to enlighten the role of a novel design technique aiming to relieve the stress field around the connector. According to this technique, part of the connector’s web is left uncovered, forming the so-called “Relieving Space”, assisting the unconstrained deformation of the connector. Both traditional and innovative sensing techniques were employed in an effort to obtain data from the interior of the three-material-complex (marble-cementitious material-titanium). Analysis of the data indicated that the “Relieving Space” reduces the overall stiffness of the system, protecting marble in case of over-loading. Moreover, it was concluded that the innovative techniques employed provide pre-failure indicators well in advance of the catastrophic failure of the specimens.

Keywords monuments of cultural heritage      marble epistyles      pressure stimulated currents      acoustic emission      digital image correlation     
Corresponding Authors: S. K. KOURKOULIS   
Online First Date: 21 March 2019    Issue Date: 10 July 2019
 Cite this article:   
E. D. PASIOU,I. STAVRAKAS,D. TRIANTIS, et al. Marble epistyles under shear: an experimental study of the role of “Relieving Space”[J]. Front. Struct. Civ. Eng., 2019, 13(4): 767-786.
 URL:  
http://journal.hep.com.cn/fsce/EN/10.1007/s11709-019-0515-9
http://journal.hep.com.cn/fsce/EN/Y2019/V13/I4/767
Service
E-mail this article
E-mail Alert
RSS
Articles by authors
E. D. PASIOU
I. STAVRAKAS
D. TRIANTIS
S. K. KOURKOULIS
Fig.1  Columns and epistyles of the Parthenon Temple. (a)The marble blocks are kept in place without any intermediate adhesive material between them; (b)“I”-shaped elements joining epistyles placed either linearly or angularly with respect to each other.
Fig.2  Damaged “connections” of the Parthenon Temple. (a) Fracture of the metallic connector; (b)fracture of the marble volume.
Fig.3  The protocol in situ implemented by Zambas [6]. (a) The specimens; (b) detail of one marble volume; (c) the “I”-shaped steel connector; (d) pouring molten lead in the groove
Young’s modulus
[GPa]
yield stress
[MPa]
elongation at max stress
[%]
ductility
[%]
smax
[MPa]
n
minimum value 105.8 369.6 11.2 32.5 462.3 0.325
maximum value 113.1 401.5 13.6 45.2 498.2 0.340
Tab.1  Mechanical properties of the titanium bars used in the restoration project of the Parthenon Temple on the Acropolis of Athens
Fig.4  (a1) An overview of a typical specimen; (a2) the “immovable” epistyle and the groove; (b) the titanium connector; (c) a detailed view of the groove of a CF-type of specimen (completely filled with cement-based material); (d) a detailed view of the groove of an RS-type of specimen (partially filled with cement-based material)
Fig.5  The experimental set-up
Fig.6  (a) The fractured specimen of the CF type; (b) the final state of the connector
Fig.7  The load imposed versus the displacement of the moving traverse of the loading frame for the CF type of specimen
Fig.8  The distance between the constituent marble blocks of the CF-type of specimen as it was measured by (a) the two traditional clip-gauges and (b) the DIC system
Fig.9  (a) The procedure used to determine the displacement field of the cement based filling material along the common plane of the two marble blocks: The elementary areas of this material isolated on either side of the interfacial plane (the plane of contact of the two blocks) are clearly shown. (b) the displacements of the as above elementary areas along the axis of the connector (horizontal- left plot) and along the loading axis (vertical- right plot) against the load applied
Fig.10  The strains developed at three strategic points of the web of the connector, as they were measured by electrical strain gauges glued at its intermediate section (interface of the two blocks) and on either side of this section (one from the side of the moving marble volume and one on the side of the fixed marble volume)
Fig.11  (a) The fractured specimen of the RS type; (b) the plastically deformed connector
Fig.12  The load imposed versus the displacement of the moving traverse of the loading frame for the RS-type of specimens
Fig.13  The relative distance between the constituent marble blocks of the RS-type of specimen as it was measured by (a) the two traditional clip-gauges; (b) the DIC system
Fig.14  The strains developed at strategic points of the web of the connector of the RS-type of specimen as measured by properly glued electrical strain gauges
Fig.15  The PSC recorded by the electric sensors versus time for the whole duration of the experiments for the (a) CF and (b) RS types of specimens, in juxtaposition to the time variation of the load imposed
Fig.16  The normalized cumulative number of the acoustic events recorded at various parts of the marble blocks versus time for the whole duration of the experiments for the (a) CF and (b) RS types of specimens, in juxtaposition to the time variation of the load imposed
Fig.17  The spatial distribution of the acoustic events for (a1, a2, a3) the CF- and (b1, b2, b3) RS-specimens . Figures 17(a1) and (b1) correspond to the events produced until a load level equal to 17 kN, while Figs. 17(a2) and (b2) to the events produced from the load level of 17 kN until the fracture of the specimens. Finally Figs. 17(a3) and (b3) exhibit the total number of events recorded during the whole loading procedure
Fig.18  The Average Frequency (AF) versus the Rise Time per Amplitude (RA) of the acoustic signals for (a) the CF- and (b) the RS- types of specimens for the whole duration of the tests, as recorded by sensors attached on the “movable” epistyle near the flange of the groove from which fracture started (a1, b1) and away from this flange (a2, b2); (c)The position of the sensors
Fig.19  The crucial role of the method used to measure the displacements.
Fig.20  The time evolution of the cumulative energy of the acoustic signals and of the Pressure Stimulated Currents in juxtaposition to the respective evolution of the load applied to the specimens, for CF (a) and the RS (b) type of specimens.
Fig.21  The time evolution of the PSC in juxtaposition to the respective evolution of the number of hits (the latter were recorded by two sensors attached on the “movable” epistyle near the flange of the groove from which fracture started (a1, b1) and away from this flange (a2, b2).
1 M Korres, Ch Bouras. Study for the Parthenon’s restoration. Athens: Ministry of Culture, Committee for the Conservation of the Acropolis Monuments, 1983
2 C Zambas. Structural repairs to the monuments of the Acropolis- The Parthenon. Proceedings of the Institution of Civil Engineers. Civil Engineering, 1992, 92(4): 166–176
https://doi.org/10.1680/icien.1992.21497
3 Th Skoulikidis. Deterioration des materiaux de construction et notamment des marbres par la corrosion de l’ acier incorpore. Cas de l’Acropole. In: Proc 1st Int. Symp. on the Deterioration of Building Stones, Centre de Recherches et d’Etudes Océanographiques, La Rochelle: Les Imprimeries Reunies de Chambery, 1972, 41–45.
4 S Angelides. Replacement of steel connectors by titanium alloy, The Acropolis: Problems-studies-measures to be taken. In: Proc 2nd Int. Symp. on the Deterioration of Building Stones, Athens: National Technical University of Athens, 1976, 351–352
5 E E Toumbakari. Analysis and interpretation of the structural failures of the orthostate in the northern wall of the Athens Parthenon. Strain, 2009, 45(5): 456–467
https://doi.org/10.1111/j.1475-1305.2008.00529.x
6 C Zambas. Study for the restoration of the Parthenon (vol. 3b). Athens: Ministry of Culture, Committee for the Conservation of the Acropolis Monuments, 1994
7 S K Kourkoulis, E D Pasiou. Interconnected epistyles of marble monuments under axial loads. International Journal of Architectural Heritage, 2015, 9(3): 177–194
https://doi.org/10.1080/15583058.2012.756079
8 The Venice Charter. International charter for the conservation and restoration of monuments and sites. IInd Int. Congress of Architects and Technicians of Historic Monuments. Venice: ICOMOS, 1964
9 D Triantis, I Stavrakas, E D Pasiou, G Hloupis, S K Kourkoulis. Innovative experimental techniques in the service of restoration of stone monuments- Part II: Marble epistyles under shear. Procedia Engineering, 2015, 109: 276–284
https://doi.org/10.1016/j.proeng.2015.06.233
10 S K Kourkoulis, E D Pasiou, I Stavrakas, G Hloupis, D Triantis, K Moutzouris. An experimental study of the mechanical response of a typical epistyles’ connection under pure shear. In: Kowalawski Z, eds. Proceedings of the 39th Solid Mechanics Conference. Poland: Zakopane, 2014, 125–126
11 A G Tassogiannopoulos. A contribution to the study of the properties of structural natural stones of Greece. D issertation for the Doctoral Degree. Athens: National Technical University of Athens, 1986
12 P S Theocaris, E Coroneos. Experimental study of the stability of Parthenon. Publications of the Academy of Athens, 1979, 44: 1–80
13 G E Exadaktylos, I Vardoulakis, S K Kourkoulis. Influence of nonlinearity and double elasticity on flexure of rock beams – II. Characterization of Dionysos marble. International Journal of Solids and Structures, 2001, 38(22–23): 4119–4145
https://doi.org/10.1016/S0020-7683(00)00252-3
14 S K Kourkoulis, G E Exadaktylos, I Vardoulakis. U-notched Dionysos-Pentelicon marble in three point bending: The effect of nonlinearity, anisotropy and microstructure. International Journal of Fracture, 1999, 98(3/4): 369–392
https://doi.org/10.1023/A:1018614023542
15 C J Livadefs. The structural iron of the Parthenon. Journal of the Iron and Steel Institute, 1956, 182: 49–66
16 E Lamprinou. The policy of interventions in the restoration of the north colonnade of Parthenon: The case of capitals. Archaeognosia, 2001, 13: 139–151
17 A Marinelli, S A Papanicolopulos, S K Kourkoulis, I Vayas. The pull-out problem in restoring marble fragments: A design criterion based on experimental results. Strain, 2009, 45(5): 433–444
https://doi.org/10.1111/j.1475-1305.2008.00519.x
18 E D Pasiou. Experimental and numerical study of a double “T” shaped connector under pure shear. Thesis for the Inter-departmental Program of Post Graduate Studies “Protection of Monuments”. Athens: National Technical University of Athens, 2008
19 A Vrouva. Investigation for the interconnections of the epistyles of the Parthenon’s north colonnade. Athens: Ministry of Culture, Committee for the Conservation of the Acropolis Monuments, 2007
20 E D Pasiou. Connection of ancient monuments’ structural members by means of metallic connectors and suitable mortar: Experimental study with the aid of innovative techniques and numerical simulation. Dissertation for the Doctoral Degree. Athens: National Technical University of Athens, 2014
21 I Stavrakas, D Triantis, Z Agioutantis, S Maurigiannakis, V Saltas, F Vallianatos, M Clarke. Pressure Stimulated Currents in rocks and their correlations with mechanical properties. Natural Hazards and Earth System Sciences, 2004, 4(4): 563–567
https://doi.org/10.5194/nhess-4-563-2004
22 L Obert. Use of Subaudible Noise for the Prediction of Rock Bursts. Bureau of Mines, Report R13555. 1941
23 M, OhtsuRilem T C. Acoustic emission and related NDE techniques for crack detection and damage evaluation in concrete. Materials and Structures, 2010, 43(9): 1187–1189
https://doi.org/10.1617/s11527-010-9640-6
24 C Anastasiadis, D Triantis, C A Hogarth. Comments on the phenomena underlying pressure stimulated currents (PSC) in dielectric rock materials. Journal of Materials Science, 2007, 42(8): 2538–2542
https://doi.org/10.1007/s10853-006-0690-7
25 F Vallianatos, D Triantis. Is pressure stimulated current relaxation in amphibolite a case of non-extensivity? Europhysics Letters, 2012, 99(1): 18006 (EPL)
https://doi.org/10.1209/0295-5075/99/18006
26 D Triantis, I Stavrakas, A Kyriazopoulos, G Hloupis, Z Agioutantis. Pressure stimulated electrical emissions from cement mortar used as failure predictors. International Journal of Fracture, 2012, 175(1): 53–61
https://doi.org/10.1007/s10704-012-9701-7
27 M A Sutton, C Mingqi, W H Peters, Y J Chao, S R McNeill. Application of an optimized digital correlation method to planar deformation analysis. Image and Vision Computing, 1986, 4(3): 143–150
https://doi.org/10.1016/0262-8856(86)90057-0
28 Ch F Markides, S K Kourkoulis. The stress field in a standardized Brazilian disc: The influence of the load-ing type acting on the actual contact length. Rock Mech Rock Engng, 2012, 45(2): 145–158
29 S K Kourkoulis, F Markides Ch, P E Chatzistergos. The Brazilian disc under parabolically varying load: Theoretical and experimental study of the displacement field. International Journal of Solids and Structures, 2012, 49(7–8): 959–972
https://doi.org/10.1016/j.ijsolstr.2011.12.013
30 K Ohno, M Ohtsu. Crack classification in concrete based on acoustic emission. Construction & Building Materials, 2010, 24(12): 2339–2346
https://doi.org/10.1016/j.conbuildmat.2010.05.004
31 D G Aggelis. Classification of cracking mode in concrete by acoustic emission parameters. Mechanics Research Communications, 2011, 38(3): 153–157
https://doi.org/10.1016/j.mechrescom.2011.03.007
32 S K Kourkoulis, I Dakanali, E D Pasiou, I Stavrakas, D. TriantisAcoustic Emissions versus Pressure Stimulated Currents during bending of restored marble epistyles: Preliminary results. Fracture and Structural Integrity, 2017, 41:536–551
Related articles from Frontiers Journals
[1] Eric N. LANDIS, Roman KRAVCHUK, Dmitry LOSHKOV. Experimental investigations of internal energy dissipation during fracture of fiber-reinforced ultra-high-performance concrete[J]. Front. Struct. Civ. Eng., 2019, 13(1): 190-200.
[2] Limin SUN, Ji QIAN. Experimental study on wire breakage detection by acoustic emission[J]. Front Arch Civil Eng Chin, 2011, 5(4): 503-509.
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed