Pre-Test Nonlinear Finite Element Response Simulation of the BNCS Full-Scale Five-Story Reinforced Concrete Building
To support the BNCS project, a detailed three-dimensional nonlinear finite element model of the structure was developed and used for pre-test response simulations to predict the response of the test specimen, support the seismic test protocol design, and guide the instrumentation layout for both the structure and NCSs. This challenging research study was accomplished in three phases.
In the first developmental phase of this project, I started by educating myself on the nonlinear mechanics of reinforced concrete and the proposed computational framework that we were planning to use. To validate the framework and to develop some appreciation and confidence in the level of fidelity of the proposed finite element modeling techniques, I performed a series of experimental validation studies and benchmark tests on reinforced concrete components and subassemblies.
After gaining knowledge and experience on the proposed computational framework, in the second phase of the research, I developed the three-dimensional nonlinear finite element model of the BNCS structure and served the BNCS team with response simulation results. The simulation results were used to design the nonstructural components and systems and decide on the shake table test protocol, scaling of the shake table test motions, and instrumentation layout.
In the third phase of this research project, after completion of the BNCS shake table tests and collecting the measured responses of the building during the seismic tests. Utilized as blind prediction, the pre-test simulated results were then compared with the experimental measurements at different response levels varying from global structural level to component levels to local sensor levels. The objective of this final phase of the research was to evaluate the predictive capability of the employed FE modeling techniques. Considering the real-life conditions and configurations of the full-scale shake table building specimen, the performed experimental-analytical comparisons provided realistic metrics to evaluate the accuracy and fidelity of the employed nonlinear finite element response simulation technique. Moreover, as a complementary part of this phase of the research, the sources of discrepancies between the FE predictions and experimental measurements were scrutinized.
The following video compares the pre-test FE (blind) predicted response components with the experimental counterparts for denali earthquake (67% scale). The blind predictions show an overall good agreement with the experimental results.