Pseudodynamic testing and verification of simplified buckling restrained components

The nonlinear behavior of a structure under severe earthquake is difficult to predict if the corresponding mathematical model is unknown or too complicated to be identified. The Pseudo- Dynamic Test (PDT) is a combination of numerical analysis and experimental test that can emulate the dynamic behavior of structures under environmental loading such as seismic event. The step-by-step Newmark explicit integration method is applied together with the help of NI-6031E data acquisition card and INSTRON 8800 material testing machine to conduct the experimental task. In PDT the restoring force of the nonlinear specimen is measured and fed back to the numerical model to predict the displacement of next step. In order to construct a PDT apparatus, the SIMULINK toolbox and the Real-Time Window Target package provided by the MathWorks, Inc. are integrated to serve as the communication medium to the INSTRON 8800 controller. A few critical calibration procedures are also suggested in this study to ensure the precision and accuracy of experimental measurements. A nonlinear hysteresis model of the simplified buckling restrained component (SBRC) are used and identified based on the result of standard loading protocol suggested by AISC. The numerical results are also compared with the experimental data measured from PDT.