Report - PEER - University of California, Berkeley
Report - PEER - University of California, Berkeley Report - PEER - University of California, Berkeley
I’ for the ductile case, as expected. Figure 8b shows that decreasing the variability ofthe demand and capacity variables changes the brittle structure’s distribution to a(more-or-less) ‘Type I’ one, and Figure 8c shows that an increase in variability hasthe opposite effect for the ductile structure.(a) Brittle & ductile base cases: cases 1 & 2(b) Brittle + low variability: case 3 (c) Ductile plus high variability: case 4Figure 8. Predicted distributions for ‘brittle’ and ‘ductile’ base cases.Figure 9. Comparison of predictions with HAZUS methodology for base cases.Figure 9 compares the damage predicted by HAZUS for the brittle and ductilebase cases with those from the present study. The ‘brittle’ and ‘ductile’ structure havethe same yield strength and deflection, and the expected deflection is below thatcorresponding to strength reduction in the brittle structure for the adopted input406
spectrum. Hence the expected deflection is the same for both brittle and ductilestructures, and the only parameter that HAZUS has available to affect the distributionis the β value, given fixed values of the threshold deflections (Table 4). As the βvalue changes from 0.7 to 1.3, it can be seen from Fig 4 that the HAZUS distributionshape changes from fully ‘Type I’ to something approaching ‘Type II’, although theshape is not as markedly bi-modal as for the brittle base case from this study. Thebeta value for the HAZUS calculation represents a combination of the effect ofground motion (demand) and structural variabilities (β d and β c in Table 3); thecombined effect of β d =β c =0.5 (the base case considered here) is broadly equivalentto a combined β of about 1 to 1.3. It may be noted that there appears to be no obviousreason why brittleness and a high value of structural variability should be linked, andthe Monte Carlo model used here shows a marked advantage in this respect.Finally, two actual damage distributions recorded after Kocaeli were chosen(cases 5 & 6 of Tables 2 & 3, but numbered 4 & 7 in Table 1). The parametersavailable in the model were varied within reasonable bounds to see how closely themodel distribution could match the recorded ones. The two right hand columns forcases 5 & 6 in Table 3 show the parameters chosen; the deflection values of Table 4were assumed to remain applicable. The resulting distributions are shown in Figure10. They are not of course in any way predictions, but the exercise suggests thatreasonable results may be obtained from the model. Whether the building populationrecorded by CAR Ltd really was so much more ductile than that of the populationrecorded by RMS Inc. is of course another question.(a) CAR Ltd data for Izmit (b) RMS Inc data for Izmit South EastFigure 10. Comparison of simulations from this study with Izmit data.5. CONCLUSIONSA weakness in the current HAZUS methodology for predicting earthquake losses isthat it cannot directly account for the effect of structural brittleness or ductility ondamage distributions, and is no better in this respect than intensity based methods.407
- Page 370 and 371: 46.4 58 58 58 58 58 58 58 58 58 58
- Page 372 and 373: EXTENSIONS OF THE N2 METHOD — ASY
- Page 374 and 375: The strength reduction factor due t
- Page 376 and 377: The relations apply to SDOF systems
- Page 378 and 379: in X-direction pushover curves prac
- Page 380 and 381: As an example, an idealized force-d
- Page 382 and 383: The IN2 curve can be used in the pr
- Page 384 and 385: HORIZONTALLY IRREGULAR STRUCTURES:
- Page 386 and 387: Dutta and Das (2002, 2002b and refs
- Page 388 and 389: They tested the procedure on three
- Page 390 and 391: Table 1. Properties of the 4 WallsW
- Page 392 and 393: The following is a summary of two s
- Page 394 and 395: ectangular concrete deck supported
- Page 396 and 397: REFERENCESAlmazan, J. L., and J. C.
- Page 398 and 399: Rosenblueth, E. (1957). “Consider
- Page 400 and 401: instantaneous period of vibration a
- Page 402 and 403: value of the maximum plastic deform
- Page 404 and 405: (a) elastic-perfectly plastic type(
- Page 406 and 407: where a is the constant peculiar to
- Page 408 and 409: Referring to Eq. (15), the natural
- Page 410 and 411: -The effective period obtained by u
- Page 412 and 413: eal damage data, rather than theore
- Page 414 and 415: liquefaction-induced damage. This i
- Page 416 and 417: Figure 5. Selected damage distribut
- Page 418 and 419: Figure 6. Idealized capacity spectr
- Page 422 and 423: This study has shown that a modific
- Page 424 and 425: thickness of the inner wall is usua
- Page 426 and 427: 4. EARTHQUAKE GROUND MOTION INPUT A
- Page 428 and 429: 5.2 Performance Levels and Limit St
- Page 430 and 431: where λ I jis the occurrence rate
- Page 432 and 433: intensity VI because the number of
- Page 434 and 435: and thus are not considered in seis
- Page 436 and 437: The values of the displacement modi
- Page 438 and 439: constant amplitude loading (CA) or
- Page 440 and 441: deterioration. These are the type o
- Page 442 and 443: members, is the main feature of the
- Page 444 and 445: RESULTS, DISCUSSIONS AND CONCLUSION
- Page 446 and 447: systems, where FEMA estimations are
- Page 448 and 449: The case study is a Hospital in the
- Page 450 and 451: Table 1. Dimensions and amount of r
- Page 452 and 453: 4.2 Incremental AnalysisBase shear
- Page 454 and 455: When adding jackets to columns, the
- Page 456 and 457: storyShear in interior Column [ton]
- Page 458 and 459: PERFORMANCE-BASED SEISMIC ASSESSMEN
- Page 460 and 461: 2. HYBRID FRAME BUILDINGSTwo precas
- Page 462 and 463: 15’ - 0” 15’ - 0”Hybrid fra
- Page 464 and 465: and maximum residual inter-story fr
- Page 466 and 467: As the first step in understanding
- Page 468 and 469: Table 3. Comparison of calculated m
I’ for the ductile case, as expected. Figure 8b shows that decreasing the variability <strong>of</strong>the demand and capacity variables changes the brittle structure’s distribution to a(more-or-less) ‘Type I’ one, and Figure 8c shows that an increase in variability hasthe opposite effect for the ductile structure.(a) Brittle & ductile base cases: cases 1 & 2(b) Brittle + low variability: case 3 (c) Ductile plus high variability: case 4Figure 8. Predicted distributions for ‘brittle’ and ‘ductile’ base cases.Figure 9. Comparison <strong>of</strong> predictions with HAZUS methodology for base cases.Figure 9 compares the damage predicted by HAZUS for the brittle and ductilebase cases with those from the present study. The ‘brittle’ and ‘ductile’ structure havethe same yield strength and deflection, and the expected deflection is below thatcorresponding to strength reduction in the brittle structure for the adopted input406
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