The interventions for the main dome of Hagia Sophia throughout its history and a preservation proposal (original) (raw)
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Structural Maintenance of Hagia Sophia
Structural Maintenance of Hagia Sophia, 2020
For nearly fifteen hundred years, Hagia Sophia is one of the most important and well-known monuments in the history of architecture and still the fourth biggest temple in the world. Moreover, according to architectural and engineering standpoints in the construction period, Hagia Sophia is an exceptionally innovative masonry structure which completed in the 6th century. Besides the collapse of the dome 20 years after completion and secondary damages and partial collapses, the structure stands for more than 1500 years. Many serious earthquakes happened in the history of Hagia Sophia and thanks to the high performance of outstanding against these events, providing the structural, engineering and material information in order to understand the innovations in the structure and vulnerabilities might be helpful for the initial steps for the innovations in Byzantine architecture. The paper explains the structure, architectural background of Hagia Sophia and the innovations by the collaboration of different material usage and experimental process of the construction. Within the framework of this paper, a series of analyses concerning the synthesis of structural improvements through innovations. Keywords: Hagia Sophia; masonary; dome; materials; inovation;
Principle of structural restoration for Hagia Sophia Dome
WIT Transactions on the Built Environment, 1997
The present study includes 1) measurements of natural frequencies by ambient vibrations, 2) estimation of the Young's modulus for the used materials based on dynamic measurements for the domes and minarets, and 3) finite element three dimensional elasto-plastic analysis (FEM) in both cases of dead and earthquake loads, for the dome considering the effects of the supporting structure. The discussions on structural behaviors lead a principle for structural restoration for Hagia Sophia.
Structural characteristics of Hagia Sophia: I—A finite element formulation for static analysis
Building and Environment, 2007
The historic Hagia Sophia in Istanbul, which held the record as the world's largest domed building for some 800 years, is analysed with a finite element formulation, including the effects of thickness shear deformations and the term z=R, to understand its structural behaviour under the action of static loading. The structure, including all essential elements of the system, is modelled by using the same curved trapezoidal finite element with 40 degrees of freedom. Its structural behaviour and its structural load carrying system are demonstrated and the results are compared with those obtained earlier and also with those observed at the structure.
Intervention scenarios on the basilica of San Gaudenzio Dome in Novara
This paper deals with possible intervention scenarios on the XIX century dome of the Basilica of San Gaudenzio in Novara. This outstanding masonry structure, erected by Alessandro Antonelli between 1844 and 1880 at the completion of the XVII century Basilica, is composed of two superposed tambours, surmounted by an ogival dome (or gran tazza), in turn topped by a 30 m high spire which reach the 117.5 m level. The dome suffered stability problems immediately after its completion, causing an uninterrupted sequence of maintenance actions, including Danusso's major interventions, carried out between 1930 and 1946, in which reinforced concrete has been extensively utilized. The monument still presents significant cracking at the lower edge of the radial platbands, at the columns of the lower level, and along the ribs-shell interface of the gran tazza. This fact justifies a certain level of concern about the safety of the structure, and has suggested the precautionary installation of two steel hoops at the base of the dome. Current strengthening philosophy is oriented towards a more general cautious approach, which includes: (i) extensive structural investigations, (ii) reliable numerical modeling, and (iii) careful evaluation of possible intervention scenarios, which will take advantage of the most recent technological innovations. Structural investigations encompass characterization tests of materials, dynamic characterization tests of the overall structure, and a long term monitoring program, which aims at sheding light on the actual static behavior of the monument, and on the effectiveness of the recent interventions. Numerical modeling attempts to reproduce the experimental behavior of the structure, taking into account the actual material constitutive laws (masonry, stone, concrete, etc...), and utilizing the dynamic measurements in the calibration process. Possible interventions have been considered, consisting of locating "smart" steel ties: (i) in the radial platbands; (ii) at the lower order columns; (iii) around selected levels of the dome. These tie bars will act in series with Shape Memory Alloys Devices (SMADs) comprising Ni-Ti superelastic wires. The SMADs are suitably post-tensioned in order to guarantee a constant compressive force on the support and they are capable of limiting the maximum forces applied to the masonry, thus preventing structure failures caused by excessive loads.
A Simplified Strengthening Methodology for Minaret Structures in Turkey: Hagia Sophia Case
International Journal of Architectural Engineering Technology, 2017
Considering various types of historical buildings in Turkey, mosqs are the most common ones. Mosqs have minaret structures standing along next to the main body with dome. The minaret buildings with their own architectural and structural characteristics, are representing the cultural and historical change in different periods over the centruies. Minarets from Ottomon period are the most widespread ones in Turkey. With its cultural synthesis through out the history, minarets from Ottomon period differ from the others with structural capability. Since Turkey is a earthquke prone country, it is very important to make existing historical structures stronger against to the seismic loads. Recently, historical structures have been strengthened with fiber reinforced polymer (FRP) composites. There are numerous of research studies are available related with strengthening using FRP composites. From this standing point, in this research, a simplified and practicale strengthening methodlogy is proposed. For the investigation Hagia Sophia Minaret structures has been used as a case study. In the analysis part, Hagia Sophia Minaret structures have been investigated through time history analyses before and after FRP composite strengthening. As a result of the present research work, displacements and stress values are determined for comparison of the structural behavior of minaret structures.
WIT Transactions on the Built Environment, 2004
Discussed in the present article is an original structure for strengthening ancient stone-built domes, whose seismic resistance is to be enhanced. The solution consists of a thin reinforced concrete shell provided with a support ring and placed above the dome. Connecting members project downwards from the shell and are introduced in the midst of the dome’s stone. The resulting reinforcement is achieved by creation of an interconnected stone-reinforced concrete structure. Stress concentrations in the connection areas are a specific problem of the interconnected structures. While said structures are subject to static loads and seismically originated forces, problems are considered relating to the stressstrain state of the stone dome and how its dynamic characteristics are influenced by the number and location of connecting members. Issues of stress concentration located in surrounding connecting members are discussed. The problem under study is considered through an example of a real ...
A Literary and Structural Analysis of the First Dome on Justinian's Hagia Sophia, Constantinople
T he first dome of Hagia Sophia in Constantinople, perhaps the greatest structural and artistic innovation in Justinian's church, is lost to us forever. Its precise shape and size are not recorded in the written or visual records; nor does an approximation of it survive in architectural filiations. Completed sometime in 537 C.E., the dome lasted just over twenty years before a series of earthquakes in 557 led to the collapse of the eastern main arch in May 558. Deprived of this support, portions of the dome and eastern semidome fell with the arch, and the rest of the dome was cleared away for rebuilding. In his ekphrasis written for the second consecration of the building in 563, Paul the Silentiary describes the collapse this way: Now the wondrous curve of the half-sphere, although resting on powerful foundations, collapsed and threw down the entire precinct of the sacred house.... Yet, the broad-breasted fane did not sink to the foundations... but the curve of the eastern arch slipped off and a portion of the dome was mingled with the dust: part of it lay on the floor, and part-a wonder to behold hung in mid-air as if unsupported .... following describes the dome and the primary structural components supporting it and cites some of the structural movements that have taken place over the years [Figure 2]. Of a broad, rectangular basilican plan, Hagia Sophia is oriented roughly on an east-west axis. The crown of the present dome (A), which is just over 100 Byzantine feet in diameter, hangs 178.3 feet (55.6 m) above the floor.5 Four main piers (B), made mostly of limestone and greenstone ashlars, define the corers of the central 100-foot square of floor that lies beneath the dome. They rise 74.17 feet (23.14 m)6 and are spanned by four thick semicircular arches of brick (C), which are bound together by brick pendentives (D). These culminate at 133 feet (41.5 m) in a somewhat deformed circle of flat marble blocks upon which the dome rests (E). The blocks jut out several feet into the central space, forming a cornice used as an inner walkway around the dome's base. The main east and west arches serve as the terminations of the two main semidomes (F) which, being roughly full quarterspheres, have a slightly smaller surface radius than the main dome. The semidomes extend the nave to nearly its full length, and are each supported by the main piers and two secondary piers toward each end of the nave (G). The semidomes and secondary piers serve as the principal east-west buttresses to the dome, main arches, and main piers.7 To the north and south, 66 JSAH / 55:1, MARCH 1996 L9 VIHdOS VIOVH NO 3hNO(I LSMII :OyIAVI 9b8 1 u! !iessoj addssn! pue a.edseg spaiq!4y. aqT Xq paejua9 se 'e!idoS e!1eH Jo auwop!uuas UJapsea pue awop 1J4uaD aqlI :1 3IEnDJ :>-O < 1 1 FIGURE 2: Isometric cutaway view of Hagia Sophia as it is today (modified from Mainstone, Hagia Sophia). The dome (A) rests upon the cornice (E), which forms a ring at the top of the pendentives (D). The main arches (C) spring from massive stone piers (B), which rise from the corners of the central I 00-foot square. The secondary piers (G) help to support the semidomes (F). Mainstone shows that these latter elements effectively buttress the dome and the east and west main arches. The buttresses to the north and south (H) have been somewhat less successful in countering the lateral thrusts of the dome and main arches. external buttresses (H), rising nearly to the height of the main arch crowns, are joined by arches and walls to the main piers and the superstructure above them. The present dome, parts of which have survived for 1,400 years, rises 48 feet (15.0 m) from the level of the upper cornice, just slightly short of a hemisphere.8 It is made of brick and pozzolanic mortar. Anchored to the cornice, and thus indirectly to the arches, it is pierced at the base by forty arched windows. Between the windows thick radial ribs rise to the crown; the webs, well integrated with the ribs, are somewhat recessed, with an average thickness of about 2 /2 feet.9 On the outside, the ribs broaden into equally spaced spurs extending out about 7 feet, which serve as radial buttresses for the dome. Isidorus the Younger, nephew of one of the original architects, designed the second dome. He decided to demolish the remainder of the first dome and start afresh, attacking the structural problem at the level of the arches. Agathias provides a few interesting facts about the rebuilding: Since Anthemius had long been dead, Isidore the younger and the other engineers reviewed among themselves the former design and, by reference to what had remained, they judged the part that had fallen down, i.e., its nature and its faults. They left the east and west arches as they were in their former places, ? but in the case of the north and south ones they extended inward that part of the construction which lies on a curve and gradually increased its width so as to make them [the north and south arches] agree more closely with the others and observe the harmony of equal sides. In this way they were able to reduce the unevenness of the void and to gain a little on the extent of the space, i.e., that part of it which produced a rectangular figure. Upon these [new] 68 JSAH / 55:1, MARCH 1996 -%I.oe -0