Seismic Response Analysis of a Semi-active-controlled Base ...

Table 8 Identified system characteristics of the entire buildingNS directionEW directionIdentification Natural NaturalNatural NaturalModeDampingDampingMethodperiod frequencyperiod frequencyfactorfactor[s] [Hz][s] [Hz]Initial2.58 0.39 9% 2.56 0.39 7%ARX 3.20 0.35 19% 3.10 0.36 24%1stN4SID 3.23 0.31 18% 3.23 0.31 17%Direct 3.25 0.31 14% 3.21 0.31 16%Initial0.77 1.29 9% 0.77 1.30 7%ARX 0.68 1.47 17% 0.71 1.41 16%2ndN4SID 0.70 1.42 6% 0.72 1.38 8%Direct 0.71 1.41 9% 0.72 1.38 8%Table 9 Identified system characteristics of the superstructureNS directionEW directionIdentification Natural NaturalNatural NaturalModeDampingDampingMethodperiod frequencyperiod frequencyfactorfactor[s] [Hz][s] [Hz]Initial1.32 0.76 2% 1.26 0.79 2%ARX 1.10 0.91 5% 1.10 0.91 2%1stN4SID 1.16 0.86 2% 1.11 0.90 8%Direct 1.18 0.85 2% 1.20 0.83 2%Initial0.48 2.10 6% 0.47 2.11 5%ARX 0.36 2.80 8% 0.37 2.70 4%2ndN4SID 0.47 2.12 7% 0.40 2.51 10%Direct 0.44 2.27 7% 0.45 2.22 4%REFERENCESMita, A. (2003). “Health Monitoring and Identification.” Structural Dynamics for Health Monitoring,Chap. 5, 84-96.Van Overschee, P. and De Moor, B. (1994). “N4SID: Subspace Algorithms for the Identification ofCombined Deterministic-Stochastic Systems.” Automatica, Vol. 30, No. 1, 75-93.Yoshida, K. (2001). “First Building with Semi-Active Base Isolation.” Journal of the Japan Society ofMechanical Engineers, Vol. 104, No. 995, 698-702.1036