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Alpha-Coefficient2.06_RCS_S, gen1.8 mean = 0.496_RCS_S, nf1.6 median = 0.45 α6_S_S, gen1.4 σ = 0.1256_S_S, nf12_RCS_S, gen1.212_RCS_S, nf1.06_RCS_P, genCase Study, Fig. 4b0.80.60.40.2(1.65,0.45)0.01.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0Multiplier, C(a)Figure 6 – Optimization of S a R α Sa ,(a) Range of optimum α-C pairs and (b) Dispersion on α-C pairs.common calibration is desired to make the procedure convenient for generalized use. Referringto Fig. 6b, on average the dispersion turns out to be relatively constant over a large range of Cand α pairs. Further, from Fig. 6a we see that the optimal α (given C) is relatively stable for 2
already low when scaled by spectral acceleration alone. Comparing results for the average twoparameterindex (Eq. 10) with Sa(T 1 ), the two-parameter index reduces the range of dispersionfrom 0.24-0.45 for Sa(T 1 ) to 0.19-0.29 for SaR Sa 0.5 .S a R Saα1.00.5α = 0.5T F = 2.0T 1CM92-RIOLA92-YERLP89-HCALP89-HSPLP89-WAHOMiyagiMendocinoValparaisoαS a R Sa1.00.5α = 0.5T F = 2.0T 10.00.00 0.02 0.04 0.06 0.08 0.10 0.12IDR MAX0 2 4 6 8 10 12 14λ u(a)(b)0.5Figure 7 – Updated Behavior Curves with IM = S a R Sa(a) IDA and (b) stability curves0.06. PROBABILITY ASSESSMENT OF COLLAPSE PREVENTIONUsing the inelastic time-history and stability analysis method described above, the “collapseprevention” performance for a given set of ground motion records is defined by the stabilitylimit,µˆλ f, defined in terms of the seismic hazard intensity – either Sa(T 1 ) or SaR 0.5 Sa . The nextstep in the performance assessment is to compare the stability limit to the seismic hazard,considering the uncertainty in both the calculated response indices and the site hazard curve.Mean Annual Probability of ExceedanceDefining failure (collapse) by the likelihood of the ground motion intensity exceeding thestability limitP fµˆλ fthe mean annual probability of collapse can be described by the following:[ ≥ µˆ ]= P IM(11)λfWhere P f is the mean annual probability of failure and IM is the seismic hazard demandexpressed using an intensity measure consistent with that used to define the stability limit,µˆλ f.In this case, the two alternative intensity measures considered are S aT ) or( 1SaR Sa0.5. The13
Page 1 and 2: DEVELOPMENT OF A TWO-PARAMETER SEIS
Page 3 and 4: development of seismic hazard maps
Page 5 and 6: S a( T f) . Inoue (1990) provides t
Page 7 and 8: 6 @ 4m = 24mW530x92W610x101W610x101
Page 9 and 10: While the two-parameter index reduc
Page 11: significantly degrade. This point,
Page 15 and 16: whereIM is the hazard intensity mea
Page 17 and 18: 1e-1IBC CodeY-B PSHA1e-1IBC CodeY-B
Page 19 and 20: elated to the reduced dispersion ac

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