Report - PEER - University of California, Berkeley
Report - PEER - University of California, Berkeley Report - PEER - University of California, Berkeley
Fig. 5 shows the actual applications of the ground motions in the PDTs for theCFT/BRB frame specimen. As noted above, four earthquake ground accelerationsscaled to three different PGAs were planned for the PDT of the CFT/BRB framespecimen. However, some unexpected events encountered during the testing. In theTest No. 1, due to the buckling of the gusset plate occurred at the brace to beamconnection in the first story, the test stopped at the time step of 12.3 second. Thenstiffeners were added at the free edges of all the gusset plates underneath the threefloor beams. Then test resumed using the same ground accelerations as Test No.1 butin reversed direction. Until Test No.4, the PDT test was stopped at the time step of12.54 second as the crack on the top of concrete foundation near the gusset plate forthe south BRB-to-column joint were observed. After one pair of angles was installedbracing the stiffener to the two anchoring steel blocks, the test resumed again byapplying the same earthquake acceleration as that proceeded in Test No. 4. After all, atotal of six PDTs were conducted, and all the BRBs were not damaged. Therefore,cyclic increasing uniform story drifts were imposed until the failure of the BRBs.Since the scheduled PDT and cyclic tests were completed with failures only inbracing components including the BRBs, UBs and the gusset plates, it was decidedthat Phase-2 tests be conducted after repairing the damaged components. It adoptedthe same two earthquake records but scaled to match the spectral acceleration at thefirst mode period to the specified earthquake hazard levels. The ground motionaccelerations applied in Phase 2 PDTs are also shown in Fig. 5 (Chen et al. 2004). Allthe key analytical predictions and the experimental responses were broadcasted froma website (http://cft-brbf.ncree.gov.tw).Acceleration (m/sec 2 )8Test No.14 50/50-12.62 secTCU082EW0-4Test No.250/50TCU082EWTest No.310/50-ILP89g04NSTest No.42/50-12.54 secTCU082EWTest No.52/50TCU082EWTest No.610/50-IILP89g04NS-80 50 100 150 200 250 300Time (sec)Acceleration(m/sec 2 )1050-5-10Test No.1TCU08210/50Phase2Figure 5. Ground acceleration time history in PDTs.Test No.2LP89g042/500 25 50 75Time (sec)5. ANALYTICAL MODELS5.1 PISA3D ModelIn the application of PISA3D, all BRBs were modeled using the two-surface plastic(isotropic and kinematic) strain hardening truss element (Fig. 6). All the beammembers were modeled using the bi-linear beam-column elements (Fig. 7).Considering the strength degrading behavior of the concrete, all the CFT columnswere modeled using the three-parameter degrading beam-column elements as shown250
in Fig. 8. A leaning column is introduced in the PISA3D frame model in order tosimulate the 2nd order effects developed in the gravity columns.Figure 6. Two-surfaceplasticity hardening trusselement.5.2 OpenSees ModelFigure 7. Bilinearelement model.Force (kN)4002000-200EXPPISA3DOpenSeesS24-400-8 -4 0 4 8Drift Ratio (% radian)Figure 8. Drift ratio andforce hysteresis of CFTcolumn.All the CFT columns and steel beams of the frame are modeled by the flexibilitybasednonlinear beam-column fiber elements with discretized fiber section model.The uniaxial bilinear steel material model (Steel01) is the basic model thatincorporates isotropic strain hardening adopted in the analyses. The uniaxial Kent-Scott-Park concrete material model (Concrete01) is adopted and no tensile concretestrength is considered. All BRBs were modeled using the truss element. TheMenegotto-Pinto steel material (Steel02) with isotropic and kinematic strainhardening was used for the truss element. A leaning column arrangement has alsobeen adopted in OpenSees model. The frame model presented in this paper utilizesthe measured material properties of steel beams, CFT tubes, and the infill concrete forthe CFT columns.6. ANALYTICAL AND EXPERIMENTAL RESULTSFigs. 9 and 10 present the roof experimental displacement time history, and the 1 stinter-story drift versus story shear relationships obtained in Test No. 5. The peakvalue of roof displacement is about 208-mm and the peak story drift is at 1 st story ofabout 0.025 radian. It is evident that the roof displacements and the brace hystereticbehavior simulated either by PISA3D or OpenSees shown in Figs. 9 and 10 aresatisfactory. Fig. 11 shows the peak story shear distributions under the applications of50/50, 10/50 and 2/50 three earthquake load effects. It is confirmed that the analyseshave predicted the experimental peak shears extremely well. Fig. 12 shows thatexcept the roof floor, experimental peak lateral floor displacements well agree withthe target design responses for both the 10/50 and 2/50 two events. Tests (Fig. 13)also confirmed that experimental peak inter-story drifts of 0.019 and 0.023 radianswell agree with the target design limits 0.02 and 0.025 radians prescribed for the10/50 and 2/50 events, respectively.251
- Page 216 and 217: where & x&(t ) = acceleration at th
- Page 218 and 219: science building. The lateral load-
- Page 220 and 221: emain the same, the magnitude of sl
- Page 222 and 223: of sliding thresholds, are desirabl
- Page 224 and 225: Retrofit of Nonstructural Component
- Page 226 and 227: was developed to accommodate these
- Page 228 and 229: tested by Meinheit and Jirsa are us
- Page 230 and 231: where D is the maximum drift and N
- Page 232 and 233: in predicting damage as well as rep
- Page 234 and 235: 4.2.2 Modeling the Data Using Stand
- Page 236 and 237: that the defining demand using a no
- Page 238 and 239: • The influence on the dynamic re
- Page 240 and 241: deviations σ and correlation coeff
- Page 242 and 243: The first three modes of vibration
- Page 244 and 245: Details about the ten records selec
- Page 246 and 247: to allow a quantitative assessment
- Page 248 and 249: Cornell A. C., F. Jalayer, R. Hambu
- Page 250 and 251: limited possibilities of overcoming
- Page 252 and 253: uildings, up to five stories high (
- Page 254 and 255: Efficiency η, %100806040203D-RWBW-
- Page 256 and 257: Table 1. Performance criteria for c
- Page 258 and 259: Because the analytical model strong
- Page 260 and 261: REFERENCESAguilar, G., R. Meli, R.
- Page 262 and 263: tests of its type ever conducted. T
- Page 264 and 265: end work-point to work-point). And
- Page 268 and 269: 3Roof Disp. (mm)250200150100500-50-
- Page 270 and 271: Base Shear (kN)Base Shear (kN)40002
- Page 272 and 273: 8. CONCLUSIONSBased on the test and
- Page 274 and 275: REAL-TIME DYNAMIC HYBRID TESTING OF
- Page 276 and 277: :::::2004) can be formulated using
- Page 278 and 279: The structure to be simulated is di
- Page 280 and 281: measurements, to the modeling of th
- Page 282 and 283: Figure 8. Two stories (left) and hy
- Page 284 and 285: ROLES OF LARGE-SCALE TEST FOR ASSES
- Page 286 and 287: mid-height in the third story, at w
- Page 288 and 289: cycles were repeated for each ampli
- Page 290 and 291: the tests with ALC panels were excl
- Page 292 and 293: the relationship between the moment
- Page 294 and 295: attachment details adopted for inst
- Page 296 and 297: FULL-SCALE LABORATORY TESTING: STRA
- Page 298 and 299: economic losses resulting from the
- Page 300 and 301: 4. OBJECTIVES AND OUTCOME OF STRUCT
- Page 302 and 303: 15001000500Shear [kN]0-8.0 -6.0 -4.
- Page 304 and 305: 5.1 3D Tests on a Torsionally Unbal
- Page 306 and 307: Non-linear substructuring was recen
- Page 308 and 309: PERFORMANCE BASED ASSESSMENT — FR
- Page 310 and 311: 4 x 50 m = 200 mC1 C2 C3h u = 7 mh
- Page 312 and 313: some procedures are (contrary to th
- Page 314 and 315: 5 th floor disp. [cm]0.60.0-0.6CC =
in Fig. 8. A leaning column is introduced in the PISA3D frame model in order tosimulate the 2nd order effects developed in the gravity columns.Figure 6. Two-surfaceplasticity hardening trusselement.5.2 OpenSees ModelFigure 7. Bilinearelement model.Force (kN)4002000-200EXPPISA3DOpenSeesS24-400-8 -4 0 4 8Drift Ratio (% radian)Figure 8. Drift ratio andforce hysteresis <strong>of</strong> CFTcolumn.All the CFT columns and steel beams <strong>of</strong> the frame are modeled by the flexibilitybasednonlinear beam-column fiber elements with discretized fiber section model.The uniaxial bilinear steel material model (Steel01) is the basic model thatincorporates isotropic strain hardening adopted in the analyses. The uniaxial Kent-Scott-Park concrete material model (Concrete01) is adopted and no tensile concretestrength is considered. All BRBs were modeled using the truss element. TheMenegotto-Pinto steel material (Steel02) with isotropic and kinematic strainhardening was used for the truss element. A leaning column arrangement has alsobeen adopted in OpenSees model. The frame model presented in this paper utilizesthe measured material properties <strong>of</strong> steel beams, CFT tubes, and the infill concrete forthe CFT columns.6. ANALYTICAL AND EXPERIMENTAL RESULTSFigs. 9 and 10 present the ro<strong>of</strong> experimental displacement time history, and the 1 stinter-story drift versus story shear relationships obtained in Test No. 5. The peakvalue <strong>of</strong> ro<strong>of</strong> displacement is about 208-mm and the peak story drift is at 1 st story <strong>of</strong>about 0.025 radian. It is evident that the ro<strong>of</strong> displacements and the brace hystereticbehavior simulated either by PISA3D or OpenSees shown in Figs. 9 and 10 aresatisfactory. Fig. 11 shows the peak story shear distributions under the applications <strong>of</strong>50/50, 10/50 and 2/50 three earthquake load effects. It is confirmed that the analyseshave predicted the experimental peak shears extremely well. Fig. 12 shows thatexcept the ro<strong>of</strong> floor, experimental peak lateral floor displacements well agree withthe target design responses for both the 10/50 and 2/50 two events. Tests (Fig. 13)also confirmed that experimental peak inter-story drifts <strong>of</strong> 0.019 and 0.023 radianswell agree with the target design limits 0.02 and 0.025 radians prescribed for the10/50 and 2/50 events, respectively.251
Change language