Seismic evaluation of a renovated wooden hypostyle structure: A case study on a mosque designed with the combination of Asian and Byzantine styles in the Seljuk era (14th century AD)

Wooden hypostyle structures are primarily built using timber-framed construction types, surrounded by masonry walls on two or three facades. This construction technique is a combination of Asian (wooden frame) and Byzantine (masonry wall) techniques. The primary load-bearing system in these structures consists of multiple rows of wooden pillars. This paper focuses on the restoration of a historical wooden hypostyle mosque constructed in 1366. The mosque is a crucial example of wooden hypostyle tradition in the Anatolia region of Turkey. The study consists of four steps: field survey, lab tests, restoration practices, and seismic performance analyses for the examined structure. The on-site examination includes the visual inspection of material deterioration and the analyses of obtained samples from different places of the structure. Moreover, a building survey was carried out using three-dimensional laser scanning. Secondly, a laboratory study was performed using the samples gathered from the structure. The physical tests revealed that while the stone sample taken from the minaret had the highest porosity, the stone sample represents the west facade displayed the lowest porosity. Accordingly, the water absorption capacity of the stone sample taken from the west facade was the lowest. On the other hand, among samples, this stone sample had the highest wet and dry density. In the third step, the renovation process of the mosque considering its originality is presented. Lastly, the seismic performance level of the renovated structure is obtained using three analyses: linear, pushover, and kinematic approaches. Story drift ratios of the structure at the performance points for three earthquake ground motion levels meet the target performance requirements. Considering the realistic behavior of the material, the vulnerability of the main structure against the maximum credible earthquake is revealed in terms of tensile and shear stresses. The seismic vulnerability of the minaret is also determined in terms of both tensile and shear stresses and the story drifts ratios in both analysis types. We believe that the structural restoration processes presented in this paper to bring back a deteriorated historical mosque to its original form will provide a comprehensive approach to the literature.