Bi-directional ground motions with two orthogonal horizontal values are required to predict seismic response of high-rise and complicated buildings using time history analysis. By reviewing current methods of selecting and scaling bi-directional ground motion records,it points out shortcomings of the Chinese codes in this aspect. In addition,based on the bi-directional maximum acceleration( BdMA) spectrum,the BdMA method of selecting and scaling ground motion records was developed. Nonlinear time history an...