Permanent displacement of a bridge column can be directly measured during the inspection after near-fault earthquakes. However, the engineer needs to estimate the expected residual drift at the design stage to determine if the bridge seismic performance is satisfactory. The most direct method to estimate the residual displacement is nonlinear response history analysis, which is time consuming and cumbersome. Alternatively, an attractive but indirect method is generating estimated residual displacement spectra that depend on displacement ductility demand, column period, site conditions, and earthquake characteristics. Given the period and the expected displacement ductility demand for the column, the residual drift response spectra curves can be utilized to estimate the residual drift demand. Residual drift spectra that are applicable to RC bridge columns in different parts of the United States were developed based on nonlinear response history analyses using a comprehensive collection of recorded and synthetic near-fault ground motions and were linked to one-second spectral acceleration (S₁) of the AASHTO maps. It was also found that the residual drift ratio is below one percent when S₁ is less than 0.6 g.

在发生近断层地震后的检查过程中，可以直接测量桥柱的永久位移。但是，工程师需要在设计阶段估计预期的残余漂移，以确定桥梁的抗震性能是否令人满意。估计残余位移的最直接方法是非线性响应历史分析，这既费时又麻烦。另外，一种有吸引力但间接的方法是生成估计的残余位移谱，该谱取决于位移延性需求，柱周期，工地条件和地震特征。给定柱的周期和预期的位移延展性需求，可以使用残余漂移响应谱曲线来估计残余漂移需求。AASHTO图的S ₁）。还发现，当S ₁小于0.6g时，残余漂移率低于百分之一。