## 4 Numerical and Experimental Investigation of MR Semi-Active Control
### Displacement Response  
The results in Tables 1 and 2 are the peak interlayer drift response of the continuous control and switching control test. The values in parentheses are numerically simulated values. Figure 10 is the time displacement history diagram of the isolation layer measured by two control conditions under two kinds of intensities. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Earthquake Magnitude** & \multicolumn{3}{c}{**Max Acc. 0.126 g**} & \multicolumn{3}{c}{**Max Acc. 0.36 g**} & \multicolumn{3}{c}{**Max Acc. 0.72 g**} \\ \hline Earthquake & El Centro & Taft & Tianjin & El Centro & Taft & Tianjin & El Centro & Taft \\ ground motion & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake \\ \hline Isolation layer & 1.57 (2.09) & 1.67 (2.50) & 3.52 (6.70) & 3.76 (7.74) & 6.66 (8.52) & 28.2 (20.0) & 11.71 (15.4) & 14.16 (17.9) \\ First floor & 1.04 & 1.13 & 1.67 & 1.36 & 2.00 & 5.94 & 2.86 & 3.41 \\ Second floor & 0.59 & 0.62 & 0.83 & 1.04 & 0.86 & 4.77 & 1.73 & 1.60 \\ Third floor & 0.53 & 0.48 & 1.02 & 0.85 & 1.14 & 4.16 & 1.79 & 1.63 \\ Fourth floor & 0.45 & 0.57 & 0.71 & 0.73 & 0.95 & 3.85 & 1.31 & 1.69 \\ Fifth floor & 0.40 & 0.43 & 0.83 & 0.65 & 0.72 & 3.19 & 1.40 & 1.41 \\ Sixth floor & 0.26 & 0.28 & 0.45 & 0.44 & 0.55 & 1.31 & 0.88 & 0.81 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The peak interlayer drift under different seismic inputs in continuous control (mm). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Earthquake Magnitude** & \multicolumn{3}{c}{**Max Acc. 0.126 g**} & \multicolumn{3}{c}{**Max Acc. 0.36 g**} & \multicolumn{3}{c}{**Max Acc. 0.72 g**} \\ \hline Earthquake & El Centro & Taft & Tianjin & El Centro & Taft & Tianjin & El Centro & Taft \\ ground motion & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake & earthquake \\ \hline Isolation layer & 1.32 (4.40) & 1.43 (3.02) & 2.8 (1.29) & 2.78 (4.31) & 5.00 (4.20) & 15.94 (17.5) & 7.60 (10.88) & 16.48 (11.11) \\ First floor & 0.91 & 1.23 & 1.5 & 1.95 & 3.58 & 4.62 & 3.72 & 5.52 \\ Second floor & 0.57 & 0.54 & 0.91 & 1.29 & 1.69 & 1.55 & 2.39 & 2.91 \\ Third floor & 0.43 & 0.62 & 0.90 & 1.07 & 1.98 & 2.27 & 2.16 & 3.18 \\ Fourth floor & 0.37 & 0.34 & 0.75 & 0.92 & 1.42 & 2.06 & 1.82 & 2.52 \\ Fifth floor & 0.34 & 0.32 & 0.61 & 0.85 & 1.50 & 2.63 & 1.70 & 2.82 \\ Sixth floor & 0.29 & 0.28 & 0.46 & 0.85 & 0.84 & 1.08 & 1.31 & 1.69 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The peak interlayer drift under different seismic inputs in switch control (mm). It can be seen that from above tables, the displacement response of the structure under three kinds of intensities is well controlled by the control under two control conditions. The maximum displacement (28 mm) of the isolation layer is only half the maximum displacement (55 mm) of the rubber bearing under three working conditions. The reduction in the displacement of the isolation layer ensures that the isolation rubber bearing work safely in the event of an extreme earthquake. As can be seen from the table above, the displacement of the isolation layer (which are control effect determinants) and the experimental results are close to the numerical results under two control conditions. This lays a foundation for further research on the design method of the control system. In addition, the displacement of the isolation layer measured by tests is generally less than the numerical results. This should be the result of a multifaceted interaction, such as the inaccuracy of the model and damper parameters, the errors of calculation and measurements, etc. This is the next step where further research is required. For switch control, the displacement of the isolation layer is relatively small because it changes only between the maximum and minimum damping forces.