Restoration of Mireuksaji Stone Pagoda: Evaluation of Reinforced Granite Members with Titanium Bars

Granite is one of the most common stones used historically in Korean architecture. Given the abundance of high-quality granite, more than 90% of the pagoda structures in Korea–tiered towers with multiple eaves—were built using this stone. Recognition and understanding of the structural behavior of this material are crucial for preservation of these pagodas. Hence, material properties of granite such as compressive and tensile strength, and Young’s modulus were investigated by conducting tests from quarries having undergone comparable differentiation processes with stones having similar mineral composition. To enhance the mechanical behavior of the stone and efficiency, a proposal to reinforce the stone through use of titanium bars was suggested. Subsequently, a series of experiments were also performed to determine strength dependency. Several pullout tests using resin epoxy were made to determine bond behavior between the two. Here, granite specimens were reinforced at the center of a single titanium bar having varied lengths and diameters. Experimental results indicated that upon reaching effective development length, larger embedment length did not result in increased tensile strength.