Abstract 

Remodeling aging structures is common to enhance their structural, economic, and functional performance. However, the exceeding of bearing capacity of existing piles caused by increased upper loads due to vertical expansion frequently hinders their revitalization. In this paper, a methodology is proposed to control the demand-to-capacity ratio of existing piles without retrofitting the foundation, which is often accompanied by technical limitations and safety issues. A total of 12 tests were performed on four full-scale specimens, with tendon shape, wall thickness, boundary condition, and construction sequence as variables. Factors affecting load-transfer performance were identified based on test results. The target load-transfer pattern implemented in accordance with the tendon shape was confirmed. To verify the validity of the method, tests using tendon shape and wall thickness as variables were compared with results from finite element analysis