In this paper a modeling method is validated at multiple scales for the seismic performance of mu... more In this paper a modeling method is validated at multiple scales for the seismic performance of multiblock tower structure (MTS). MTS are a proposed concept for large‐capacity gravitational energy storage that will enable renewable energy sources. The structure modeled is a tower of 7144 nominally identical blocks arranged in a 38‐layered annular pattern with no adhesive mechanisms between the blocks or the blocks and the foundation. The level set discrete element method is used to model the dynamics of the tower structure experiencing a ground motion. Experimental determination of each model parameter is shown from the use of individual blocks before construction. Close comparisons to experimental results are shown for the dynamic motion of the tower over a full ground motion time history for multiple scales, materials and ground motions. When the tower was brought to failure, the two ground motions used produced distinct failure modes of the tower showing both a peeling and buckling behavior. Both the effect of the friction coefficient and unequal block heights are investigated. Friction coefficient has a noticeable effect on the amplitude of motion of the tower while the unevenness of the block heights affects mostly the structural speed.
5 In this paper, Bayesian linear finite element (FE) model updating is applied for uncertainty 6 ... more 5 In this paper, Bayesian linear finite element (FE) model updating is applied for uncertainty 6 quantification (UQ) in the vibration-based damage assessment of a seven-story reinforced concrete 7 building slice. This structure was built and tested at full scale on the USCD-NEES shake table: 8 progressive damage was induced by subjecting it to a set of historical earthquake ground motion 9 records of increasing intensity. At each damage stage, modal characteristics such as natural fre10 quencies and mode shapes were identified through low amplitude vibration testing; these data are 11 used in the Bayesian FE model updating scheme. In order to analyze the results of the Bayesian 12 scheme and gain insight into the information contained in the data, a comprehensive uncertainty 13 and resolution analysis is proposed and applied to the seven-story building test case. It is shown 14 that the Bayesian UQ approach and subsequent resolution analysis are effective in assessing uncer15 tainty...
Since, at present, it is impossible to eliminate the various sources of uncertainty related to ea... more Since, at present, it is impossible to eliminate the various sources of uncertainty related to earthquake loading, it is necessary to better understand their effects on structural seismic response. Such studies are needed for the development of seismic design procedures providing structural robustness in the face of uncertainty. This paper examines a methodology allowing to quantify the uncertainty contained in earthquake ground motion time histories and to assess the resulting structural response variability.
Model Validation and Uncertainty Quantification, Volume 3, 2019
Bayesian nonlinear finite element (FE) model updating using input and output measurements have em... more Bayesian nonlinear finite element (FE) model updating using input and output measurements have emerged as a powerful technique for structural health monitoring (SHM), and damage diagnosis and prognosis of complex civil engineering systems. The Bayesian approach to model updating is attractive because it provides a rigorous framework to account for and quantify modeling and parameter uncertainty. This paper employs the unscented Kalman filter (UKF), an advanced nonlinear Bayesian filtering method, to update, using noisy input and output measurement data, a nonlinear FE model governed by a multiaxial material constitutive law. Compared to uniaxial material constitutive models, multiaxial models are typically characterized by a larger number of material parameters, thus requiring parameter estimation to be performed in a higher dimensional space. In this work, the UKF is applied to a plane strain FE model of Pine Flat dam (a concrete gravity dam on King’s River near Fresno, California) to update the time-invariant material parameters of the cap plasticity model, a three-dimensional non-smooth multi-surface plasticity concrete model, used to represent plain concrete behavior. This study considers seismic input excitation and utilizes numerically simulated measurement response data. Estimates of the multi-axial material model parameters (for the single material model used in this study) are non-unique. All sets of parameter estimates yield very similar and accurate seismic response predictions of both measured and unmeasured response quantities.
A full-scale five-story reinforced concrete building specimen, outfitted with a variety of nonstr... more A full-scale five-story reinforced concrete building specimen, outfitted with a variety of nonstructural components and systems (NCSs), was built and tested on the Network for Earthquake Engineering Simulation at the University of California, San Diego (NEES–UCSD) large outdoor shake table in the period March 2011–June 2012. The building specimen was subjected to a sequence of dynamic tests including scaled and unscaled earthquake motions. A detailed three-dimensional nonlinear finite-element (FE) model of the structure was developed and used for pretest response simulations to predict the seismic response of the test specimen and for decision support in defining the seismic test protocol and selecting the instrumentation layout for both the structure and NCSs. This paper introduces the building specimen and the shake table test protocol and describes the techniques used for the nonlinear FE modeling and response simulation. Utilized as blind prediction, the pretest simulation results at different scales (global structural level and local member/section/fiber levels) are compared with their experimental counterparts for seismic input (base excitation) of increasing intensity from serviceability to design levels. The predictive capabilities of the used FE modeling techniques are evaluated and possible sources of discrepancies between the FE predictions and experimental measurements are investigated and discussed.
In this paper a modeling method is validated at multiple scales for the seismic performance of mu... more In this paper a modeling method is validated at multiple scales for the seismic performance of multiblock tower structure (MTS). MTS are a proposed concept for large‐capacity gravitational energy storage that will enable renewable energy sources. The structure modeled is a tower of 7144 nominally identical blocks arranged in a 38‐layered annular pattern with no adhesive mechanisms between the blocks or the blocks and the foundation. The level set discrete element method is used to model the dynamics of the tower structure experiencing a ground motion. Experimental determination of each model parameter is shown from the use of individual blocks before construction. Close comparisons to experimental results are shown for the dynamic motion of the tower over a full ground motion time history for multiple scales, materials and ground motions. When the tower was brought to failure, the two ground motions used produced distinct failure modes of the tower showing both a peeling and buckling behavior. Both the effect of the friction coefficient and unequal block heights are investigated. Friction coefficient has a noticeable effect on the amplitude of motion of the tower while the unevenness of the block heights affects mostly the structural speed.
5 In this paper, Bayesian linear finite element (FE) model updating is applied for uncertainty 6 ... more 5 In this paper, Bayesian linear finite element (FE) model updating is applied for uncertainty 6 quantification (UQ) in the vibration-based damage assessment of a seven-story reinforced concrete 7 building slice. This structure was built and tested at full scale on the USCD-NEES shake table: 8 progressive damage was induced by subjecting it to a set of historical earthquake ground motion 9 records of increasing intensity. At each damage stage, modal characteristics such as natural fre10 quencies and mode shapes were identified through low amplitude vibration testing; these data are 11 used in the Bayesian FE model updating scheme. In order to analyze the results of the Bayesian 12 scheme and gain insight into the information contained in the data, a comprehensive uncertainty 13 and resolution analysis is proposed and applied to the seven-story building test case. It is shown 14 that the Bayesian UQ approach and subsequent resolution analysis are effective in assessing uncer15 tainty...
Since, at present, it is impossible to eliminate the various sources of uncertainty related to ea... more Since, at present, it is impossible to eliminate the various sources of uncertainty related to earthquake loading, it is necessary to better understand their effects on structural seismic response. Such studies are needed for the development of seismic design procedures providing structural robustness in the face of uncertainty. This paper examines a methodology allowing to quantify the uncertainty contained in earthquake ground motion time histories and to assess the resulting structural response variability.
Model Validation and Uncertainty Quantification, Volume 3, 2019
Bayesian nonlinear finite element (FE) model updating using input and output measurements have em... more Bayesian nonlinear finite element (FE) model updating using input and output measurements have emerged as a powerful technique for structural health monitoring (SHM), and damage diagnosis and prognosis of complex civil engineering systems. The Bayesian approach to model updating is attractive because it provides a rigorous framework to account for and quantify modeling and parameter uncertainty. This paper employs the unscented Kalman filter (UKF), an advanced nonlinear Bayesian filtering method, to update, using noisy input and output measurement data, a nonlinear FE model governed by a multiaxial material constitutive law. Compared to uniaxial material constitutive models, multiaxial models are typically characterized by a larger number of material parameters, thus requiring parameter estimation to be performed in a higher dimensional space. In this work, the UKF is applied to a plane strain FE model of Pine Flat dam (a concrete gravity dam on King’s River near Fresno, California) to update the time-invariant material parameters of the cap plasticity model, a three-dimensional non-smooth multi-surface plasticity concrete model, used to represent plain concrete behavior. This study considers seismic input excitation and utilizes numerically simulated measurement response data. Estimates of the multi-axial material model parameters (for the single material model used in this study) are non-unique. All sets of parameter estimates yield very similar and accurate seismic response predictions of both measured and unmeasured response quantities.
A full-scale five-story reinforced concrete building specimen, outfitted with a variety of nonstr... more A full-scale five-story reinforced concrete building specimen, outfitted with a variety of nonstructural components and systems (NCSs), was built and tested on the Network for Earthquake Engineering Simulation at the University of California, San Diego (NEES–UCSD) large outdoor shake table in the period March 2011–June 2012. The building specimen was subjected to a sequence of dynamic tests including scaled and unscaled earthquake motions. A detailed three-dimensional nonlinear finite-element (FE) model of the structure was developed and used for pretest response simulations to predict the seismic response of the test specimen and for decision support in defining the seismic test protocol and selecting the instrumentation layout for both the structure and NCSs. This paper introduces the building specimen and the shake table test protocol and describes the techniques used for the nonlinear FE modeling and response simulation. Utilized as blind prediction, the pretest simulation results at different scales (global structural level and local member/section/fiber levels) are compared with their experimental counterparts for seismic input (base excitation) of increasing intensity from serviceability to design levels. The predictive capabilities of the used FE modeling techniques are evaluated and possible sources of discrepancies between the FE predictions and experimental measurements are investigated and discussed.
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Papers by Joel Conte