Preliminary Evaluation of the Terrestrial Laser Scanning Survey of the Subterranean Structures at Hagia Sophia (original) (raw)
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Discovery and documentation of the Underground structures of Hagia Sophia
Hypogea, 2023
Hagia Sophia, an iconic world known monument of Late Roman-Early Byzantine architecture, is located at the heart of Istanbul and holds great importance in world architectural history. To fully comprehend its significance, it is crucial to examine the structure from all angles. The underground structures of Hagia Sophia have been investigated many times before. The first exploration and documentation attempt took place by cavers in 1986. Later, extensive studies were carried out by different caving groups and a total of 548 m of underground passages were mapped and documented. In February-July 2020, our project began with the aim of creating a 3D documentation of Hagia Sophia's underground structures. The project was led by the faculty members of the Department of Architecture at Fatih Sultan Mehmet University and Galeri Cave Research Group. Laser scanners such as Leica Blk 360 and Faro Focus 150 S were used to carry out the documentation process. Mapping of the newly discovered tunnels and the ones with level differences from the existing tunnel system was done using traditional methods due to the very narrow passages. The project led also to the discovery, mapping, and photography of new tunnels and underground structures. Consisting of 388 meters. Thus, total length of underground structures of Hagia Sophia reached to 936 meters.
Technical Annals, 2023
The terrestrial scanning project of Hagia Sophia's subterranean structures took place in 2020. This field study enabled the creation of a threedimensional point cloud model capturing the underground tunnels and structures. Subsequently, in 2022, a more detailed documentation of the older hypogeum within Hagia Sophia was conducted. This study particularly focused on the three largest subterranean structures on the site. The first of these is the passage beneath the esonarthex, delineating a structural transition between the Theodosian and Justinian periods, spanning from the fifth to the sixth centuries. Notably, the discovery of a previously unnoticed column base on the floor of this structure prompted an update to the plan of the Theodosian atrium. The second focus lies on the vaults beneath Justinian's atrium, requiring an architectural visualization update since Schneider's documentation in 1941. These subterranean structures define the boundaries of the no longer physically existing Justinian atrium, and the debris within them awaits excavation to provide further insights. The last structure examined is the hypogeum dating back to the 4th century. This structure underwent a more detailed redocumentation following a partial clean-up and has been digitally visualized.
New Findings on Hagia Sophia Subterranean and its Surroundings
BIZANTINISTICA. Rivista di studi Bizantini e Slavi - Fondazione CISAM, 2010
This article is covering the findings of our researches at the subterranean of Hagia Sophia (subterranean structures, water supply, drainage and ventilation lines, wells and cisterns. The Topkapı Palace Museum , Istanbul Archaeology Museum (acropole and I. Hill) Hippodrome areas were also included in our later researches. All of the mentioned structures are measured by architects and scaled plans are included in this article.
Georadar investigations in the central nave of Hagia Sofia, Istanbul (Turkey)
Within an interdisciplinary project to study Istanbul's Hagia Sofia, a georadar survey was carried out in the central nave to assess if the deformations of the structure previously observed could be related to a differential behavior of the subsoil caused by architectural remains underneath. This study faces an unusual challenge since it was necessary to study the space beneath the scaffolding placed for the restoration works. The survey of the central nave was successful and allowed the detection of remains of walls that probably formed the basement of a previous 18-by 22-m structure. In addition, another interesting feature was discovered 2 m below the marble mosaic in the southeastern part of the nave. Although it is not possible to define its function, it seems that there could be a close relationship between this 2-by 3-m buried structure and the marble mosaic in the floor surface. Although some structures were identified under the floor of Hagia Sofia, there are no major changes in the topography of the central nave floor.
Anatolian Studies 73, 2023
I n 2005, an interdisciplinary survey on the subterranean remains in the area of Hagia Sophia began under the direction of Çiğdem Özkan Aygün. The work was supported by the Scientific Research Projects Department of Istanbul Technical University (project nos 37268 and 43072). Archaeologists, architects, civil engineers and art historians from Istanbul Technical University-as well as a group of photographers and divers, including members of the Anatolian Speleology Group (ASPEG)-contributed to the survey. Some of the subterranean remnants of Hagia Sophia are intact structures and others are partially surviving substructures. Almost all of them were integrated into the water supply system of the city and Hagia Sophia at a certain point in their history (Özkan Aygün 2010b). Because of the building's architectural vulnerability, nondestructive methods were employed in the exploration of conduits. Wells or cisterns, which were still full of water, had to be investigated using diving techniques; in fact, the Hookah Diving System (a surface-supplied air system where divers do not have to wear high-pressure air tanks
The Wells, Subterranean Passage, Tunnels and Water Systems of Hagia Sophia in Istanbul
2006
In November 2005, a survey was begun of the wells in and around Hagia Sophia Church in Istanbul. The long-term goal of the survey is the understanding of the function of the tunnels and the water systems used for Hagia Sophia and its surroundings during the Byzantine and the Ottoman periods. Alternate research methods, such as geophysical research, will be used in future surveys. The 2005 survey examined the channels that run from under the narthex and continue northwards and the southwards of the building as well as channels that run towards the atrium, hippodrome, and garden in the north. The survey resulted in the first photos of the well-bottoms in the history of Hagia Sophia.
Use of Laser Scanner for Digital Surveying of the Sarnicli Inn and the Byzantine Cistern Underneath
Measurement methods including traditional measurement methods, topographic and photogrammetric measurement methods, measurements via laser scanning devices and aerial photogrammetric measurement methods obtained using model airplane or model helicopters are used in documentation of the cultural heritage and protected areas in our country. Although data obtained by Aerial Lidar technology accepted as advanced technology over the past decade, enables faster data comparing to others as data obtained by terrestrial laser scanners provide millimetre level accuracy close-range scanning methods are preferred in architectural facades scanning during the process of surveying of a single building. Inclusion process of a Byzantine cistern in Istanbul, Turkey, which was undiscovered for centuries, in our cultural heritage as well as surveying stages of the cistern along with the inn structure built over, using 3D scanning technology shall be described within this study.
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2013
3D modelling of architectural structures for monitoring, conservation and restoration alterations in heritage sites has special challenges for data acquisition and processing. The accuracy of created 3D model is very important. In general, because of the complexity of the structures, 3D modelling can be time consuming and may include some difficulties. 3D terrestrial laser scanning technique is a reliable and advantageous method for reconstruction and conservation of monuments. This technique is commonly acknowledged due to its accuracy, speed and flexibility. Terrestrial laser scanners can be used for documentation of the cultural heritage for the future. But it is also important to understand the capabilities and right conditions of use and limitations of this technology.
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
The LiDAR technology has aroused considerable interest in the field of structural study of historical buildings, aimed at the structural assessment in the presence of different states of stresses and at the evaluation of the health status. The interest is due mostly by the ability of generating models of the built structures being able to predetermine different levels of schematization, two-dimensional and three-dimensional, in order to be able to perform evaluation processes assigning simplified geometric contents that correspond to the physical reality of the artefacts. This paper intends to report some results of these experiences applied in archaeological domain, to the so-called Baths-Church at Hierapolis in Phrygia (Pamukkale, TR). In particular, the generation of accurate models from dense clouds and their reduction to models with simplified geometries too, is explored, with the further aim of testing automated strategies for features detection and editing process that leads to appropriate models for visual and analytical structural assessment. The accuracy and density parameters of the LiDAR clouds will be analysed to derive orthophotos and continuous mesh models, both to obtain the best results from the application of research algorithms such as region growing to detect blocks, and to allow visual analysis on digital models and not on site. The ability to determine with high accuracy both the size and the anomalies of the wall systems (out of plumb and other rotation or local mechanisms of collapse), together with the possibility of identifying the lay of the individual drywall blocks and also the signs of cracks and collapses, allow deriving suitable models both for FE (Finite Elements) analysis and DE (Discrete Elements) analysis, as well as analytical ones.