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RESULTS OF ENGINEERING ANALYSIS FOR THE RESTORATION OFST. BASIL’S CATHEDRAL (TEMPLE OF BLESSED VIRGIN’S COVER

ON THE DITCH) IN THE RED SQUARE, MOSCOW.Natalia Almazova *

The preservation of historical and cultural monuments inour country is a task of great responsibility and complexity,which may be accomplished only based on a thoroughexamination of their current condition. One of the basicconstituents of this process is a comprehensive engineeringresearch, including land measuring, site exploration,basement and foundation inspection, examination andcalculation of the bearing structures.

Presently, Kreal, a specialized company, carries out acomprehensive examination of the restoration process of theSt. Basil Cathedral “ Temple of Blessed Virgin’s Cover on theDitch” along the above-indicated lines. The work is carriedout on the basis on state-of-the art technologies andengineering tools.

All engineering and land measuring works are performed usingelectronic land measuring equipment, which helps to developa comprehensive concept of the structural condition andidentify the peculiar features of its architectural and constructivesolutions. Examination of the base and foundations, as well asother engineering land works include electric-contact dynamicreconnaissance of the ground, seismological probing of thefoundations, seismological prospecting of the upper part ofthe ground and deep radar profiling.

The structure and current conditions of the Temple sectionsare determined through a detailed visual examination thereofwith a view to the establishment of parameters of the cracksand other damages with the help of acoustic facilities. Testingof the mechanical properties was carried out by non-destructivemethods with the help of Smidt hammers (made in Switzerland),which were designed specially for ceramic tiles and similarsolutions. The search for interstices and channels in themasonry was carried out with the help of Russian-producedradars; and the identification of metal components and theirpositions – with the help of electromagnetic probing with theuse of Profometre 4; geophysical studies of the internalmasonry layers – with the help of exclusive domestically-produced tools. The architecture of the Cathedral is based ona clear-cut construction scheme – the posterior temples arelocated on a high landing along the basic diagonals as seenfrom the central tower. Four square-like churches adjoin thecentral temple corner wise. The landing of the temple iscomprised of a massive base of pillars, which are interconnectedby corridors.

Based on the results of our engineering and land measuringwork, we have developed a three-dimensional digital modelof the Temple (see Figure 1), which gave us a new vision ofthe concept based on which the Temple has been built.Primarily, all the surrounding pillars of the temple are slightlyinclined towards the central pillar. Secondly, the geometricalcenters of the pillars and landing do not coincide. Naturally,we have concluded that it happened due to an inadequatepre-construction layout. However the landing calculationmade with due account of the window and door embrasuresshowed that the pillar axes closely coincide with the gravitycenters of the landing sections. Therefore we assumed thatin the 15th century builders deliberately shifted the geometricalaxes of structures (see Figure 2). We have undertaken athorough examination of the position of the bell tower, whichhas a noticeable inclination. In 1951 Mosgorgeotrustcomtried to determine the degree of the inclination; the obtainedresult was that the shift from the stylobata cornice axis up tothe “apple” made 790 mm and 2° verticality deviation. Theresults obtained by KREAL basically coincide with theresults of Mosgorgeotrustcom (2°09’); so, a conclusion wasthat, at present, the belfry position has stabilized.

Based on the results of our in-depth seismologicalprospecting, as well as the archive materials, we inferred thatthe engineering and geological conditions of the site havethe following geological – lithologic structure: the surface ismade up of 2 – 18 m-thick fill-up soil, underneath arepredominantly alluvial 12-m - thick friable sands. One of theunfavorable features of a geological structure of the site isthat it is located on a steep slope of a preglacial valley with adegraded Jurassic aquiclude. In the framework of this researchthe surface and underground waters were not stripped to thedepth of 14 m from the surface of the earth. There is a stripfoundations under the walls of the building made of mortaredlimestone crushed rock and ashlar. In some areas the Templefoundations partially rest on previously-erected structures. Thefoundations are formed by fill-up soils and mostly loose sands.The state of the “foundation-soil” contact is unsatisfactory.

Significant deformations have been identified, which mayhave been caused by the hetergogeneity of the foundationground, presence in the base of older buried foundations,uneven load distribution in different areas and an ongoingsand boil process. The analysis of the research results shows

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that the base deformation process continues and may cause afurther deformation of the building components.The study ofthe building construction showed significant structuralchanges, which occurred in later periods; some of thesechanges have not been reflected in the available historical –archive materials. In particular, in the garret the traces of apreviously built brick vault were identified; the time, when thisvault had been built is unknown. Six 60 x 60 forged steel frameswere installed in order to support the pillars. One of the mostinteresting and complex constructive solutions is the “flat”brick ceiling in the north-west part of the temple, which islocated under these frames. The ceiling brickwork is made upof small-size vertical spirally-laid brick. At several points theceiling has been suspended so that the control-rods are directedtowards the steel forced horizontal rods (see Figure 3). In thestructures of the Temple there are multiple cracks of up to 40mm (see Figure 4). The coating of the internal gallery has beenalmost destroyed, the majority of the vaults are supported bywooden poles, which are corroded by the wood-grinder. Themajority of cracks are concentrated in the western part of thebuilding along the perimeter of the central pillar, which lookslike a foundation failure. The largest cracks are located alongthe conjunction lines between the separate parts of the building.Besides, we have identified vertical cracks in the pillar walls;the reasons for the appearance of these cracks is yet to befound.. The study of the cracks demonstrates the most intensiveformation falls was in the 1950s and then the crack formationprocess slowed down but did not stop. The measurement ofthe vibrational amplitude in the structures showed that theimpact could not adversely affect the durability of the structures.Based on the geological and physical research it can beconcluded that in numerous areas the durability of the internal

masonry layer is lower. Based on the research it can be inferredthat, despite the numerous defects, the basic structures of theTemple walls, landing and group floor overlaps are not in thestate of emergency; the coating however is in a state ofemergency. It should also be noted that there are no data onthe biochemical and physiol-chemical research. Such researchis only in its initial stage beginning and the results may bequite interesting. In particular, the said research may help toexplain the emergence of the vertical cracks in the pillar masonry.

It appears reasonable, after the completion of the comprehensiveengineering research, to carry out a detailed calculation of theTemple as a single “building – base - foundation” system withdue account of the existing damages. We believe that anapproach based on the initial examination and structurecalculation would provide optimal solutions as to therestoration of the St. Basil’s Cathedral “the Blessed Virgin’sCover on the Ditch” in Red Square in Moscow.

* Natalia Almazova

Natalia M. Almazova, doctor of science, graduated from theMoscow Civil Engeneering Institute in 1977, Civil constructionfaculty. Natalia M. Almazova is a managing director SC “KREAL”,which was established in 1992 with participation of leadingspecialists of major construction design, architectural and researchinstitutes of Moscow. SC “KREAL” owns exclusive technologies,modern state-of-the-art equipment and paraphernalia foraccomplishment of complex engineering and technical studies ofbuildings and structures of the 1st level of responsibility, includingheritage monuments of great architectural and historical value.Natalia M. Almazova has been elected to membership of theInternational Association of Quality Practitioners (Great Britain)in the grade of Fellow in 28 July 2000.

Figure 1 Figure 2

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Figure 3

figure 4