Academic literature on the topic 'Istanbul Aqueduct of Valens'

The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises distinct rigid blocks interacting along their boundaries based on the point-contact hypothesis. Thus, the discontinuous stone skeleton of the masonry aqueduct is represented explicitly in the computational model. First, a validation study was conducted on the laboratory experiment to demonstrate the capabilities of the adopted modeling approach. Then, a discontinuum model representing the Valens Aqueduct was used to assess the seismic capacity of the structure under gradually increasing lateral forces. The numerical simulations gave insight into the structural response of the aqueduct from the elastic range to total collapse. Additionally, parametric research was performed considering joint properties, namely the joint tensile strength, contact stiffness, joint friction angle, and compressive strength of the masonry, to quantify the effects of contact parameters on the displacement response of the DEM model. Further inferences were made regarding the modeling parameters, and practical conclusions were derived.

The city of Istanbul has important water system remnants from old civilizations among which water line systems begun with Byzantine period and continued during Ottoman era, including Kırkçeşme water supply system. The original gallery structure within the Kırkçeşme system has been altered with time at some places as a result of necessary planning activities, restoration and repair works. All these activities helped to keep almost the system originality. Since its first opening in 1564, its discharge increased steadily as a result of additional drainage feeding line connections to the main gallery. However, through time only a couple of the 570 additional lines have remained in operation. Although other similar establishments have perished in time without leaving even traces, the Kırkçeşme system is its vivid and harmonious appearance in front of eyes even today. Four dams were constructed at the most convenient locations along the water supply lines from 1620 to 1818. The water from the streams was collected during the rainy season and discharged to the city at times of need with increasing capacity. In general, the Kırkçeşme system has two branches: one extends towards the east, which seemed to have more water, due to its feedback from the Kirazlı, Topuz and Paşa tributaries of the Kağıthane stream; the other branch is westwards which is fed by the Ayvad Deresi, Orta Dere and Bakraç Dere tributaries of the Kağıthane stream. All the water are brought together at Başhavuz (main pool) south of Kemerburgaz, where they collectively enter the main supply line crossing the Alibey Stream over the Mağlova Aqueduct, and then joining a branch from the Cebeciköy Stream and finally flow in towards the south. In a historical document called Tezkiret'ül Bünyan, (The Book of Structures) the author states that Sinan pledged to the Sultan about the existence of some old waterways. However, the Roman waterway still remains in the vicinity of Cebeciköy, which is located at a higher elevation than the Kırkçeşme water supply line but ran parallel to it. The water supply system should have integrated perspective for operation and maintenances. On the other hand, standing structures give to humanity the impression that the stability and design carry not only water, but also valuable cultural heritage. Moreover, they connect many civilizations with each other and also past as well as future.

Abstract A hydrological and hydraulic engineering analysis has been carried out on the Valens aqueduct system constructed from around AD 345 and serving Constantinople. A GIS analysis of previous field observations combined with a digital elevation model confirmed the aqueduct’s likely route and slope. Macrophysical Climate Modelling revealed that contemporary weather data was an appropriate proxy for the time of the aqueduct’s construction, and modern flow data was obtained for some of the springs that fed the aqueduct. Existing, previously documented remains, especially at intakes, were considered, and the industry standard software HEC–RAS was used to simulate the performance of the aqueduct system with a view to understanding the amount of water it could have delivered to the city, the seasonal variation in supply and the most likely configuration of the aqueduct, where this was not clear from existing archaeology. It was concluded that the most likely configuration for the aqueduct system was a fourth and a fifth century channel continuing separately and in parallel to the city walls, which might have delivered flow the range of 0.73 m3/s in the driest month of October to 1.73 m3/s in the wettest month of March over an average year.