Transactions on the Built Environment vol 15, 1995 WIT Press, ISSN

Transcription

1 Repair and strengthening of the eastern facade wall of the western range of cells at the Byzantine monastery of St. Luke in Boeotia/Greece N. Charkiolakis, K. Floros, Th. Kantzos Directorate ofrestoration of Byzantine and Post-Byzantine Monuments, Ministry of Culture, 56 Hermou Street, Athens, Greece Abstract The four-story eastern fagade wall of the western range of cells at the byzantine monastery of St. Luke in Boeotia, according to recent architectural and structural survey, consists of approximately 20 different structural phases, dated from the byzantine period (11th century AD) until today. Its strengthening and partial restoration, which became necessary during the recent strengthening and restoration works at the second floor cells, will be carried out: First, by increasing the existing mechanical strength of its elements, with the use of cement grouting and repointing, the partial reconstruction of the masonry walls and the seaming of cracks or structural joints. Second, by reinforcing the wall and its elements, in order to undertake additional dynamic loads, using a system of horizontal zones of stainless steel ties and steel bars in the random stone masonry wall.

2 146 Dynamics, Repairs & Restoration 1 Introduction The Byzantine monastery of St. Luke, in Boeotia, is an outstanding historic monument. The buildings, dated from the 11th century AD, have a marvellous architectural unity although they were constructed in different historical periods. We mention, among them, the famous Katholikon - the main church - of St. Luke with its llth century excellent architecture and high quality mosaics; the elegant elder church oi Theotokos - the Virgin Mary - which is still in use by the monks; the partially restored old Trapeza - refectory - which has been converted to a museum of mid -byzantlne sculptures; the four-story high western and northern ranges of cells of different historical and various architectural styles etc. For all this, throughout the year, the monastery attracts thousands of pilgrims and visitors from all over the world. 2 The repair and strengthening problems During the last two years, after the monks request, a major strengthening and restoration works was carried out, at the second floor cells of the western range, by the Ministry of Culture (Directorate of restoration of byzantine and post-byzantine monuments). The western range is a four-story high building complex with walls of random stone and brick masonry and floors of stone masonry vaults and, in recent years, of reinforced concrete, and has a wooden roof covered with ceramic tiles. The eastern fagade (14 m total height and 35 m length) is composed of a retaining wall (4 m high), of two succesive series of arches (arcades) and of a series of three independent dwellings of the neoclassical period (19th century). The preliminary architectural and structural survey showed that the eastern wall consists of, at least, 20 different structural phases, dating from the mid-byzantine period (llth century AD) until today. The excessive loads caused by several additions of stories, which had not been planned initially, the mortar degradation, which was of

3 Dynamics, Repairs & Restoration 147 poor composition in materials ( lime, sand etc.), as well as the lack and the destruction of the horizontal wooden zones of ties, had as a result the appearance of serious damage (i.e. cracks, swellings, declinations, partial collapses, etc.) to crucial points of the building structural elements. A static analysis, according to the Greek Anti-seismic Regulation, proved the inability of the existing stone masonry to undertake any dynamic (i.e. seismic) loads. Observations "in situ", with the use of a high sensibility monitoring system, showed a partial inclination movement of 2 mm during the last 12 months. 3 The proposed repair and strengthening measures For the above reasons, a series of repairing and strengthening works have been studied and have being programmed for the near future, with two main aims: First, to increase the existing mechanical strength of the structural elements of the building, with the use of cement grouting and repointing, the partial reconstruction of the stone masonry wall and the seaming of the cracks. Second, the reinforcement of the walls and their elements in order to undertake additional dynamic loads using a system of horizontal zones of stainless steel ties and stainless steel bars in the random stone masonry walls (short columns) between the arches (the area in which the monastery is located, is considered to be a highly seismic zone of Greece). All the new metallic elements will be incorporated into the masonry in order to be invisible. After the completion of the above mentioned works, it will follow the restoration of the neoclassical upper part of the western building complex fagade. 4 Conclusions The strengthening and restoration works of the eastern fagade wall of the western range of cells at the Byzantine monastery of St. Luke became necessary after a long time of abandonment, a weather effect

4 148 Dynamics, Repairs & Restoration corrosion and various distructive interventions to the building structure. As the traditional techniques have been proved inadequate, the restoration of the monument will be achieved, according to the article 10 of the Venice Charter, by the use of efficient modern techniques. References 1. Barskij,V.G., Stranstvovanija Vasilija Grigorovica-Barskago po svjatym mestam Vostoka s 1723 po 1747 g., Izdany Bravo-slavnyrn Palestinsvom Obscestrom po podlinnoj rukopisi pod redakciejn N. Barsukova, Sankt-Peterburg, Schultz, R.N. & Barnsley, S.H., The Monastery of Saint Luke of Stiris inphocis, London, Imac;, ET., To oikodo^mov xpovmov ins Movng Ocriou AOUKQ <Pa)Ki8o<;, Bij3Aio0riKn ing ev AGrivaic; ApxaiohoYiKng Eiaipeiac;, api9. 65, AGrivai, Feilden, B.M., Conservation of Historic Buildings, Butterworths, London, Lizzi, F., The static restoration oj monuments, Sagep Publisher, Geneva, Mortars, Cements and Grouts used in the Conservation oj Historic Buildings, Symposium , Rome, ICCROM, Rome, Sowden, A.M., The Maintenance oj Brick and Stone Masonry Structures, E. & F.N. Spon, London, 1990.

5 Dynamics, Repairs & Restoration 149 N *- 1. KATHOLIKON 2. CHURCH OF THEOTOKOS 3. REFECTORY 4. WESTERN RANGE 5. NORTHERN RANGE Figure 1. The Byzantine monastery of St. Luke General plan, after E. Stikas. Figure 2. Isometric view of the western range of cells.

6 Cn O g 1745 AD 1783 AD = AD 1995 AD Figure 3. The western range of cells in different historical periods.

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8 en to B). M' GO seaming of structural zones ^ 8? o thorough stitching SECTION ELEVATION 0 m 10 m 20m 30 m 40 m 45 m Figure 5. The eastern fagade wall with the consolidation and strengthening measures.

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