The maximum displacement of 49 mm measured from the GPS receiver on the top of the test model is
used for calculation of deformed shapes. Deformed shapes based on the modal parameters in Figure 10
and the maximum displacement of 49 mm from the GPS receiver are compared in Figure 8. Due to the
error between the initial displacement of 50 mm and the displacement of 49 mm from GPS, besides
numerical errors in SSI method, differences in magnitudes of lateral displacement at every story level
are easily found.