A recently developed Hilbert-Huang transform (HHT) technique is applied to detect damage locations of pier systems. This technique can be effectively used to detect the locations of damages exhibiting nonlinear behavior. A series of numerical simulations are conducted for bridge pier systems with damages under a controlled sweeping load. Nonlinear plastic model proposed by Wen is adopted to describe the hysteretic behavior related to the structural damage. The results of the numerical simulation study indicate that the HHT method can reasonably identify the damage locations under severe measurement conditions with a limited number of acceleration sensors.