Un-measurable, but Inferable Attributes. Data Processing

Size: px

Start display at page:

Download "Un-measurable, but Inferable Attributes. Data Processing"

Eustace Wilcox
5 years ago
Views:

1 Identification of Civil Engineering Structures and Uncertainty Qin Pan, John Prader, Nathaniel Dubbs, A. Emin Aktan, and Franklin L. Moon Drexel University Kirk Grimmelsman University of Arkansas

identification constructed systems CONSRUCED SYSEM CHARACERISICS Conceptualization and Idealization Soil and Foundation 3D

Response Un-measurable, but Inferable Attributes BC and CC Material stiffness Intrinsic forces Damage, deterioration Capacity

Engineering New Materials, Systems Health Monitoring Knowledge Identified Model Acquisition of Data Loading and/or Excitation

Measurable Response Data Data Processing Error screening Averaging, windowing Index selection (Physics Based vs.

2 identification constructed systems CONSRUCED SYSEM CHARACERISICS Conceptualization and Idealization Soil and Foundation 3D Geometry Structural-Nonstructural Materials sampling/testing Structural Complexities -Non-stationarity -Nonlinearity Structural Response Un-measurable, but Inferable Attributes BC and CC Material stiffness Intrinsic forces Damage, deterioration Capacity Envelope Failure mode Objectives FE Model Validation Condition/Vulnerability Assessment Asset Management, Performance Based Engineering New Materials, Systems Health Monitoring Knowledge Identified Model Acquisition of Data Loading and/or Excitation -Static -Dynamic Sensor density/modality Sampling, filtering, etc. Measurable Response Data Data Processing Error screening Averaging, windowing Index selection (Physics Based vs. Data Based and other NPB ) Index identification Response Indices Parameter/Model Identification A priori modeling Objective function formulation Parameterization Optimization algorithm DECISIONS BASED ON HUERISICS

3 general research approach Implementation of developed strategies Identification of relevant challenges

4 ambient vibration monitoring and model identification of the Henry Hudson Bridge (1936, Designed by David Bernard Steinman) East Elevation

5 a priori finite element model 3D FE Model: 2414 Frame & 435 Shell Elements

6 instrumentation plan CL est on the north part of the bridge Upper Level Lower Level 19 L L V V L L L L 24 V V V 3 V V 38 V 42 V V 46 V L 52 L South Viaduct ower D East Elevation View 15 ower North Viaduct D East Side ransverse Accelerometer V East Side Vertical Accelerometer L East Side Longitudinal Accelerometer West Side ransverse Accelerometer V West Side Vertical Accelerometer L West Side Longitudinal Accelerometer V V Sensors Which Stay for the ests on North & South Part of the Bridge

7 sample results of the ambient monitoring study Upper Level Lower Level Bent No. 17 Bent No ower CL 14 24V ower

8 model uncertainty and experimental information FE Model Ambient Vibration Monitoring Common model parameters element (~12,) continuity and boundary (~18,)? Global vibration parameters 7 frequencies 7 mode shapes (8 discrete points) Inform this challenge through a transparent laboratory experiment

experimental configurations of transparent physical models Configuration 1 C-Clamps 1 2 3 4 5 6 Steel Pedestal

9 experimental configurations of transparent physical models Configuration 1 C-Clamps Steel Pedestal Steel ube 3X1.5X.125 in PCB Capacitive Accelerometer Model 371G3FA3G (typ) Configuration Steel Pedestal

10 model updating results Model A: E Model B: E, K r Run est Data Updating Initial Updated Diff Source Parameter ( 1 5 psi) ( 1 5 psi) (%) 1 Config 1 E Config 2 E Mode est f Initial f I (f I -f )/f Run 1 # (Hz) (Hz) (%) Updated f U (Hz) (f U -f )/f (%) Updating Run : Config Nominal Parameter with model A E (ksi) 29, Mode est f Initial f I (f I -f )/f Run 2 # (Hz) (Hz) (%) Updated f U (Hz) (f U -f )/f (%) Diff (%) Run est data source 3 Config 1 4 Config 2 Comparison of E 26,172.4 Updating Diff Initial Updated Parameter (%) E ( 1 5 psi) K r ( 1 4 psi) E ( 1 5 psi) K r ( 1 4 psi) Mode est f Initial f I (f I -f )/f Run 3 # (Hz) Run (Hz) 3: Config (%) 1 Updated Run f4: U (Hz) Config (f U -f2 )/f (%) with 4.91 model 4.22 B with model B , , Run 2: Config 2 with model A 19, Mode est f Initial f I (f I -f )/f Run4 # (Hz) (Hz) (%) Updated f U (Hz) (f U -f )/f (%)

11 sensitivity analysis of a priori FE model of the Henry Hudson Bridge Vertical frequencies and norms of error (Hz) from a priori model MODE #.85 E.9 E.95 E 1. E 1.5 E 1.1 E 1.15E 1.2 E 1.25 E EXP NORM divergence divergence Norm of error is defined as: NORM = 7 i= 1 FREQFEi FREQ FREQEXPi EXPi 2

12 Drexel Intelligent Infrastructure and Safety Institute heuristic-based model updating adjusted rigid off-sets corrected joint constraints removal of moment releases removal of moment releases corrected joint adjusted constraints rigid off-sets

13 sensitivity analysis of updated FE model of the Henry Hudson Bridge Vertical frequencies and norms of error (Hz) from updated model MODE #.85 E.9 E.95 E 1. E 1.5 E 1.1 E 1.15E EXP NORM divergence divergence Norm of error is defined as: NORM = 7 i= 1 FREQFEi FREQ FREQEXPi EXPi 2

14 Ambient Vibration est of Brooklyn Bridge owers

15 Spectral Peaks & Operating Deflected Shapes (single reference) Acceleration (g 2 /Hz) (g 2 /Hz) ight Above ower Base (ft) Hei 18 Peaks in -5 Hz Band (2 pure tower modes expected) Frequency (Hz) Frequency (Hz) B C E G H M Height Above ower Base (ft) Shape SHAPE YPE ype 1 1 SHAPE YPE 2 Shape ype Shape SHAPE YPE ype 3 3 Shape SHAPE ype YPE 44 Shape SHAPE YPE ype 5 5 SHAPE Shape YPE ype 6 6 Height Above ower Base (ft) Unit Normalized Amplitude Unit Normalized Amplitude Unit Normalized Amplitude Unit Normalized Amplitude

experimental configuration of transparent physical model Direct Excitation Random Finger aps C-Clamps 1 2 3 4 5 6 Steel Pedestal ransmitted Excitation

16 experimental configuration of transparent physical model Direct Excitation Random Finger aps C-Clamps Steel Pedestal ransmitted Excitation Random and Complex Excitation Cases Steel ube 3X1.5X.125 in PCB Capacitive Accelerometer Model 371G3FA3G (typ) 86 peaks in - 28 Hz band, 5 modes expected

17 operating deflection shapes for the physical model (multi-reference) Hz Hz Ch1 Ch3 Ch5 Ch2 Ch4 Ch Hz Hz Ch1 Ch3 Ch5 Ch2 Ch4 Ch Hz Hz Ch1 Ch3 Ch5 Ch2 Ch4 Ch Hz Hz Hz Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 1. Ch1 Ch2 1. Ch1 Ch2 1. Ch3 Ch4 Ch3 Ch4 Ch5 Ch6 Ch5 Ch Actual Mode 2

18 operating deflection shapes for the Brooklyn ower (multi-reference).313 Hz.381 Hz.439 Hz.566 Hz Blong Blong Blong Blong Clong Clong Clong Clong 5 Elong 5 Elong 5 Elong 5 Elong Glong Glong Glong Glong Hlong Hlong Hlong Hlong Actual Mode 1?.61 Hz.86 Hz.972 Hz 1.21 Hz Blong Blong Blong Blong Clong Clong Clong Clong 5 Elong 5 Elong 5 Elong 5 Elong Glong Glong Glong Glong Hlong Hlong Hlong Hlong

19 Static monitoring of the Commodore Barry Bridge during hanger retrofit

= ε x E x A) Isolated free body assumption Significant difference in total rod force and

20 results from hanger retrofit monitoring Hanger force Rod force Splice Coupler 7.5 Diameter SS Rod Hanger Sensors Axial forces on rods and hanger calculated Hooke s Law (F = ε x E x A) Isolated free body assumption Significant difference in total rod force and change in hanger force (176 kn [396 kip] in one case) Unaccounted force was between 23-37% (average 28%)

21 conclusions Configurable, transparent physical models can play an important role in overcoming or alleviating challenges identified during field testing (1) Parameters with low variability can serve as a check regarding the admissibility of a priori FE models for updating (2) he consistency of operating deflection shapes (obtained through processing ambient vibration data uses multiple references) can contribute to the identification of modes Structure-specific or case-specific sources of uncertainty that do not allow a generalize formulation of the challenge

22 questions Implementation of developed strategies Identification of relevant challenges

Structural Identification of Constructed and Infrastructure Systems

Structural Identification of Constructed and Infrastructure Systems SHMII-3, Vancouver Nov 15, 2007 Emin Aktan, Chair Necati Catbas,, Sub-Commitee Chair Franklin Moon, Secretary ASCE SEI Committee on Structural