Report - PEER - University of California, Berkeley

and maximum residual inter-story frame drifts were used to define the acceptancecriteria in this study. The following drift limits were used as acceptable limits for thefour performance levels: maximum transient drifts of 0.5% (EQ-I), 1.5% (EQ-II),2.5% (EQ-III) and 3.8% (EQ-IV); and maximum residual drifts of 0.1% (EQ-I), 0.3%(EQ-II), 0.5% (EQ-III) and 0.75% (EQ-IV). These limits were chosen based on theguidance given in the Blue Book and considering the re-centering nature of the hybridframes. Although it is unnecessary to set a stringent residual drift limit for the nearcollapse performance, the selected residual drift limits were 20% of the maximumtransient drifts for all earthquake levels.Spectral acceleration (g)1.61.41.21.00.80.60.40.2EQ-IVEQ-IIIEQ-IIEQ-IZone 4, Soil S cDamping = 5%0.00 1 2 3 4 5Period (s)Figure 4. Multiple-level acceleration response spectra.Acceleration (in/s 2 )300EQ-IIIEQ-IV200EQ-IEQ-II10000-10010 20 30 40 50 60 70-200-300Time (sec.)Figure 5. Earthquake input motions.451