Detecting the ground-dependent structural damages in a historic mosque by employing GPR

Abstract

This study aims to employ one of the most significant geophysical methods, known as the ground penetrating radar (GPR) method, in the determination of reasons for the underground cavities, the size of deformations and fractures in the ground and structure, the geometric behavior patterns, and the soil-structure interaction and changes in a historic structure. In addition to the instrumental examination, an observational investigation of the current situation of the mosque was also carried out. İskender Pasha Mosque, which is a rare mosque having a tabhane (guest house), is one of the important historical mosques regarded as built-in Mimar Sinan style in Diyarbakır, Turkey in 1552. The instrumental examination part of the study was conducted totally in 13 different regions of the mosque and its courtyard. Within this scope, 8 GPR measurements were taken on the ground of the mosque and its immediate environment and 5 GPR measurements were taken on the walls of the mosque. The GPR measurements indicated that there are serious subsidence anomalies under the mosque and its courtyard. Besides, there is a water table under the portico of the mosque which may lead to big problems in the future. In addition, observationally detected structural deteriorations were supported by geophysical GPR measurements. It was revealed that problems dealing with the leveling irregularities on the floor of the harim, portico, and courtyard are directly related to the anomalies under the ground. Moreover, it was achieved from both instrumental and observational investigations that the anomalies under the ground are directly the reasons for the anomalies in the walls of the mosque. GPR results demonstrated that this technique can be used effectively to determine anomalies in both the carrier system of the historic structures and the ground under the historic structures without any damage.