Structural Health Monitoring and Rapid Post-Event Assessment of Civil Infrastructures through Digital Twins

Transcription

1 Structural Health Monitoring and Rapid Post-Event Assessment of Civil Infrastructures through Digital Twins Hamed Ebrahimian, Ph.D., P.E. Senior Engineer, SC Solutions, Inc. S. Farid Ghahari, Ph.D. Assistant Project Scientist Dept. of Civil and Environmental Engineering, UCLA Ertugrul Taciroglu, Ph.D. Professor and Chair Dept. of Civil and Environmental Engineering, UCLA

2 Why Bother? Aging Infrastructures Threats Retrofit & Upgrading Limited Resources 2

3 Post-Earthquake Inspection Maintenance Inspection Visual Inspection Costly Periodic Subjective No system-level insight Hidden damage # of bridges inspection time chaos =? Intensity-based metrics can be inaccurate! Inspection complexity Hidden damage No system-level insight 3

4 SHM - NDE Point Monitoring Load Cell Fiber Optics Modal-Based Linear Damage Identification NDE Crack Sensor Source: FHWA SHRP2 Solutions Shortcomings? Data not information Limited damage detection, and quantification capability Require large number of sensors Maintenance and installation cost No system-level insight Shortcomings? Not sensitive to local damage Based on limiting assumptions (broad band excitations, etc.) inaccuracy and lack of robustness Optical Strain Gauge (Source: DOI /JRC ) Shortcomings? Traffic interruption Cost Access limitations No system-level insight 4

5 Integration of Mechanics-Based Models with Data Digital World Forward Simulation Model Parameter Uncertainties Unknown Inputs Real World Estimate Model Parameters Estimate Input Forces Mechanics-based damage diagnosis at refined spatial resolution Model Updating / training 5

6 Digital Twins Real Twin Data Mechanics-based Model Traffic Data Traffic induced Vibration Earthquake Data (Output or input-output) Digital Twin Bayesian Data Assimilation 6

7 Bayesian Data Assimilation Linear/Nonlinear FE Model Measurement Y = y Y ˆ = f ( Ψ) p( Ψ) Prior Information p( Ψ) Ψˆ, ˆ P Ψ p Likelihood Function ( Y = y Ψ) N( 0, R) Ψ p Bayesian Updating ( Ψy) = p ( Ψ y) p ( y Ψ) p( Ψ) p ( y) Ψˆ +, ˆ + P Ψ Ψ 7

8 Digital Twins for Operational Monitoring and Management Bayesian FE Model Updating (Integrating Data with Model) 2 Object Tracking / Type Detection Online Portal Permanent/temporary sensors Stochastic Filtering Mechanics-based FE Model P 1 P 2 P n Vehicle Locations 3 Acceleration THs Predictions - + Online Portal Estimate jointly the model parameters and vehicular loads Regular camera system (tripod or drone mounted) On-site laptop Office/server computer Measurements Digital Twin Share Information with Stakeholders 8

9 Box-Girder Bridge Case Study San Roque Canyon Bridge Typical prestressed cast-in-place RC box girder Concrete deterioration & rebar corrosion in Deck Concrete deterioration in Girders Loss of prestress force 9

10 Verification Study Verification using numerically simulated data Poor condition in R2 40% Reduction in Top slab f c 20% Reduction in Girder f c 20% Reduction in Tendon Prestress No damage in Bottom slab R4 R5 Accelerometers R2 R3 R1 20 unknown material parameters + Rayleigh damping parameters + Vehicular loads Top Slab f 5 regions Girder f 5 regions Bottom Slab f 5 regions Section prestress 5 regions 10

11 Verification Study 11

12 Damage Diagnosis Top Slab f c Girders f c Top Slab Girders Bottom Slab Tendons Tendon Prestress Strain Bottom Slab f c 12

13 Digital Twins for Post-Earthquake Assessment Bayesian FE Model Updating (Integrating Data with Model) Permanent Sensors Stochastic Filtering Mechanics-based FE Model Output Acceleration THs Online Portal Predictions - + Estimate jointly the model parameters and foundation input motions (FIMs) 4 Measurements Digital Twin Share Information with Stakeholders 13

14 Box-Girder Bridge Case Study 14

15 Identifiability Analysis No. Description No. Description 1 Modulus of elasticity of the concrete (deck) 19 Longitudinal soil-foundation stiffness (abutment) 2 compressive strength of the concrete (columns) 20 Longitudinal soil-foundation damping (abutment) 3 Initial modulus of elasticity of the concrete (columns) 21 Transverse soil-foundation stiffness (abutment) 4 Modulus of elasticity of the bearing pad 22 Transverse soil-foundation damping (abutment) 5 Shear stiffness of the bearing pad 23 Vertical soil-foundation stiffness (abutment) 6 Mass of the embankment-abutment 24 Vertical soil-foundation damping (abutment) 7 Vertical soil-foundation stiffness (piers) 25 8 Vertical soil-foundation damping (piers) 26 9 Longitudinal soil-foundation stiffness (piers) Longitudinal soil-foundation damping (piers) Transverse soil-foundation stiffness (piers) Transverse soil-foundation damping (piers) 30 Rotational soil-foundation stiffness about the longitudinal axis (abutment) Rotational soil-foundation damping about the longitudinal axis (abutment) Rotational soil-foundation stiffness about the vertical axis (abutment) Rotational soil-foundation damping about the vertical axis (abutment) Far-field soil-embankment stiffness in the longitudinal direction Far-field soil-embankment radiation damping in the longitudinal direction Rotational soil-foundation stiffness about the longitudinal axis (piers) 31 Rotational soil-foundation damping about the longitudinal axis (piers) 32 Far-field soil-embankment material damping in the longitudinal direction Initial stiffness of the soil-backwall stiffness in the longitudinal direction Rotational soil-foundation stiffness about the transverse axis (piers) 33 Ultimate strength of the soil behind the backwall Rotational soil-foundation damping about the transverse axis (piers) 34 Initial stiffness of the shear-key Rotational soil-foundation stiffness about the vertical axis (piers) 35 Mass-proportional damping coefficient Rotational soil-foundation damping about the vertical axis (piers) 36 Stiffness-proportional damping coefficient 15

16 Validation Study Santa Cruz 2018 Eq. 16

17 Damage Diagnosis Passive Soil Force- Deformation Shear Key Force- Deformation Concrete Fiber Material Response 17

18 Acknowledgements U.S. DOT - SBIR Program Grant # 6913G618P Caltrans Contract # 65A0642 My colleagues at SC Solutions, Inc. 18

19 Thank you for your attention!