Abstract
Damage ratios concerning length, depth and area of cracks as well as width were defined and accumulated from bending tests of precast concrete piles in which crack sections were intended to be observed directly, and following conclusions were obtained. Even if PHC piles experience load level near crush of concrete in compression side, cracks close to the extent of 0.03 mm width by effects of prestress in unloading state which suggest possibility to use continuously without any repair. If residual cracks around or larger than 0.05 mm are observed, cracks may penetrate pile thickness in area over 30% of pile section, so that it may be necessary to cover cracks for continually use
