Abstract：For time history analysis of seismic response of structures, different ground motion
records or different scaling procedure to modify the ground motion records will lead to obvious
record-to-record variation. Thus how to select and modify ground motion records to reduce the
variation is necessary for improving the reliability of seismic analysis results. Aiming at
overcoming disadvantages of the modal-pushover-based ground motion scaling procedure, a new
integrated scaling factor is proposed to scale ground motion records, which uses effective modal
gravity coefficients as weight coefficients to consider the contribution of the first several
modes. For each mode, an individual scaling factor is determined by minimize the discrepancy
between the maximum displacement of the corresponding equivalent SDOF system by nonlinear time
history analysis and target displacement. Furthermore, a 6-storey reinforced concrete frame was
taken as an example structure. The modified modal-pushover-based, the modal-pushover-based and the
ASCE7-based ground motion scaling procedures were used to scale the preliminary ground motion
records for time history analysis of the example structure. Comparison of the maximum lateral
displacement and the maximum interstory drift ratio indicates that the modified modal-pushover-
based scaling procedure is better than the modal-pushover-based and the ASCE7-based ground motion
scaling procedures in the sense of reducing the variation of analytical results for seismic
responses of structures.
