Dynamic response characteristics of the Fatih mosque in Istanbul estimated from earthquake data

Abstract

Structural Health Monitoring (SHM) enables continuous recording of the dynamic response of a structure and analysis of its time-varying dynamic characteristics for condition and ultimately damage assessment. SHM is increasingly used for the estimation of dynamic behavioral characteristics of historical structures, which is vital for conservation, repair and strengthening. For the preservation of the architectural heritage, a crucial element in our present-day culture, the historical constructions need to be identi ed both in terms of their structural system and present damages. The Fatih Mosque in Istanbul is part of a larger complex. The rst mosque was built soon after the conquest of Constantinople between the years 1463 and 1470. After 1766 earthquake the rst mosque collapsed. The present mosque built in 1771 and is one of the most signi cant monuments in the city. In this study, the four-year monitoring data (2013-2016) recorded by the Fatih Mosque Structural Health Monitoring System is analyzed. The vibration monitoring system in the Fatih Mosque consists of thirteen three-component accelerometers and four two-component tilt-meters.During the four year period, the mosque experienced more than 160 earthquakes whose magnitudes varied between 2.1 and 6.5 in the Richter scale. A database of recordings suitable for further analysis is created by applying selection criteria for number of recording stations, signal to noise ratio, epicentral distance and earthquake magnitude. The data is uniformly processed using computer codes developed in MATLAB. Time domain and frequency domain characteristics of structural response are studied with the help of recorded earthquakes in the structure. Additionally presence of soil-structure interaction and rocking; and variations in wave travel times are investigated.