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Advanced Site Monitoring and Characterization of Site Dynamic Properties Mourad Zeghal, Tarek Abdoun and Vicente Mercado Department of Civil and Envir.

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Presentation on theme: "Advanced Site Monitoring and Characterization of Site Dynamic Properties Mourad Zeghal, Tarek Abdoun and Vicente Mercado Department of Civil and Envir."— Presentation transcript:

1 Advanced Site Monitoring and Characterization of Site Dynamic Properties Mourad Zeghal, Tarek Abdoun and Vicente Mercado Department of Civil and Envir. Eng., Rensselaer Polytechnic Institute, Troy, NY Anirban De Manhattan College Quake Summit 2010, October 8 - 9, 2010.

2 Outline Introduction and Objectives Shape-Acceleration Array New Array at Wildlife Refuge Site Recent Earthquake and Field Test Data Reduction and System Identification Concluding Remarks

3 Introduction Evaluation of in-Situ Soil Dynamic Properties

4 Introduction Evaluation of Soil Dynamic and nonlinear Properties: soil sample tests How representative of in-situ conditions: Stress-strain response (damping, etc.) Lateral spreading and failure

5 Objectives Install permanently a network of Shape- Acceleration Arrays (SAAs) with an optimal configuration at the NEES Wildlife refuge site Monitor the site response (acceleration, permanent displacement and pore pressure) – Future earthquakes (lateral spreading expected) – Field test(s) using T-Rex Develop efficient data reduction and system identification tools to evaluate the in situ 3D dynamic and nonlinear properties of the site

6 Shape Acceleration Array 3D measurements Accelerations Permanent displacements

7 Wireless Shape Acceleration Array Sensing SystemCost Array Depth Real Time Monitoring Capability and Comments Manual Slope Inclinometer $20,00030mNo Costs include monitoring based on 2 readings/ month for 4 months Slope Inclinometer Array $75,00030mYes 1D deformation measurement and no acceleration measurement Accelerometer Downhole Array $100, mYes Acceleration measurement at about 5m intervals and no deformation reading Wireless Shape- Acceleration Array $10,00030mYes 3D acceleration and 3D deformation measurements

8 NEES Wildlife Refuge Site Imperial Valley of Southern California Experienced multiple earthquakes and liquefaction and lateral spreading events in the past

9 NEES Wildlife Refuge Site Granular layer anticipated to liquefy during medium-size earthquakes Significant lateral spreading expected

10 Shape Acceleration Array Optimal configuration: analytical considerations and numerical simulations

11 Installation and Site Monitoring

12 Baja California Earthquake: April 4, 2010

13 Low Amplitude Site Properties

14 Field Test

15 Field Test Data

16 CMP: Control Motion Approach (prescribed motion at all sensor “node” locations, Elmikaty and Zeghal) CMP Finite Element formulation Interior node Boundary node 16 Multi-Dimensional Local Identification

17 Computational Example 17

18 Constitutive Model (Saturated Clay) Von-Mises yield criteria, multi-yield surfaces Associated flow rule Kinematic Hardening rule Shear Modulus Degradation and Reduction Visco-Elasto-Plastic Stress-Strain relation Identification Parameters Prevost,

19 Identification Stages 19

20 Identification Stages 20

21 Concluding Remarks Work in progress to develop a capability to: (1)measure cyclic and permanent displacements of field sites (2)Efficiently characterize and estimate (low and large strain) three-dimensional in situ dynamic properties Objective: Enable better understanding of liquefaction, lateral spreading and failure of sites

22 Acknowledgements This research is supported by the National Science Foundation (NEESR CMS )


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