Historic structures form a very important part of our cultural heritage and should be well protected. Therefore, full comprehension of the structural behavior of historic structures is of prior importance. A seriously damaged single domed mosque of 16th century Classical Ottoman Architecture was investigated in this study. Serious damages have been observed at various structural elements including the dome and the structural masonry walls, recently leading the structure&#039 / s closure to service. The main objective of this study is to find out the possible reasons of the damage. The Mosque was constructed on silty-clay soil and the water table has been changed considerably due to the drought in recent years causing soil displacements. The structure is modeled with linear finite element approach. The masonry walls are modeled with homogenized macro shell elements. The change in water table is imposed on the Mosque as displacement at foundation joints. The results of the analyses have been compared with the observed damage and the finite element model has been calibrated according to the observed damage. Some rehabilitation methods have also been proposed. Mini pile application up to firm soil (rock) was recommended to prevent the soil displacement. A steel ring around the damaged dome base was proposed to avoid any further propagation of cracks. Furthermore, the cracks on the masonry walls should also be repaired with a suitable material that is also compatible with the historic texture.

Recent seismic events have confirmed the long-standing belief that unreinforced masonry structures are critically vulnerable to failure during earthquakes. A substantial number of older structures in the United States have unreinforced masonry construction. Among these are important historic structures, vital to preserving regional and national heritage. Since earthquakes can likely damage these buildings, they must be protected against failure. RetrOfitting these structures should be a sensitive process, reaching beyond pure safety issues and recognizing the historical qualities of the structure. Fire Station No. One, Roanoke, Virginia, an unreinforced masonry bearing wall building, is one of the most treasured landmarks in the Roanoke Valley. Completed in 1908, the Fire Station is still operational, serving as a lifeline structure. Built in absence of any seismic codes, this structure may be at risk of failure during an earthquake. The purpose of this study is to analyze the various seismic risks that exist in Fire Station No. One and to identify any seismic deficiencies within the structure. Additionally, this thesis will suggest possible seismic strengthening measures that would be appropriate, based upon preservation and aesthetic considerations. / Master of Science

The in-situ examination of historical structures for diagnostic and monitoring purposes is a troublesome work that necessitates the use of non-destructive investigation (NDT) techniques. The methods of quantitative infrared thermography (QIRT) and ultrasonic testing have distinct importance in this regard. The key concern of the study was developing the in-situ use of QIRT for assessment of stone masonry wall sections having different sublayer(s) and failures. For that purpose, the non-destructive in-situ survey composed of QIRT and ultrasonic testing was conducted on a 16th century monument, Cenabi Ahmet PaSa Camisi, suffering from structural cracks, dampness problems and materials deterioration. The combined use of these two methods allowed to define the thermal inertia characteristics of structural cracks in relation to their depth. The temperature evolution in time during the controlled heating and cooling process was deployed for the cracks/defects inspection. The superficial and deep cracks were found to have different thermal responses to exposed conditions which made them easily distinguishable by QIRT analyses. The depth of cracks was precisely estimated by the in-situ ultrasonic testing data taken in the indirect transmission mode. The inherently good thermal resistivity of the wall structure was found to have failed due to entrapped moisture resulting from incompatible recent plaster repairs. The IRT survey allowed to detect the wall surfaces with different sublayer configurations due to their different thermal inertia characteristics. The knowledge and experience gained on the experimental set-ups and analytic methods were useful for the improvement of in-situ applications of QIRT and ultrasonic testing.