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by Sami F. Masri University of Southern California Los Angeles, California, USA Presentation at

INTERNATIONAL COLLABORATIVE ACTIVITIES IN STRUCTURAL CONTROL AND MONITORING. by Sami F. Masri University of Southern California Los Angeles, California, USA Presentation at Joint NCREE/JRC Workshop on International Collaboration on Earthquake Disaster Mitigation Research

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by Sami F. Masri University of Southern California Los Angeles, California, USA Presentation at

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  1. INTERNATIONAL COLLABORATIVE ACTIVITIES IN STRUCTURAL CONTROL AND MONITORING by Sami F. Masri University of Southern California Los Angeles, California, USA Presentation at Joint NCREE/JRC Workshop on International Collaboration on Earthquake Disaster Mitigation Research Methodologies, Facilities, Projects and Networking National Center for Research on Earthquake Engineering, Taipei, Taiwan 17-19 November 2003

  2. Outline • Introduction • International Cooperation in CE Research • Research Needs in Structural Control • IASC Working Groups • 4IWSC

  3. International Association for Structural Control (IASC) • Established in 1993 • Objectives of IASC: - Advancement of the science and practice of structural control and monitoring of civil infrastructure systems, by means of education, research and application of knowledge. - Foster international collaboration and information dissemination through the activities of its Working Groups and through the convening of periodic Workshops and Conferences

  4. Cooperative Research Types • Different aspects of the same problem could be studied in two or more countries in a coordinated program; • A large experimental project could be undertaken in one country and subsidiary projects by researchers from other countries could piggyback on the main project; • Researchers on related projects in two or more countries could meet annually in a workshop to exchange information and make recommendations for future projects.

  5. I4R Coordinating Committee Country #1 National Committee Country #2 National Committee Country #n National Committee International Initiative for Intelligent Infrastructure Research (I4R) I4R Organizational structure.

  6. I4R Coordinating Committee Working Groups Repair & Retrofit Structural Control Dynamic Loads Materials Monitoring WG1 Project 2 WG1 Project 3 WG1 Project 1 WG1 Project 4 Sample I4R Initiative

  7. I4R Coordinating Committee Research Initiative Steel Joints Monitoring Repair & Retrofit Materials Sample Topics  ·  Sensors ·  Data Acquisition/ Transmission ·  Damage detection ·  Signature Analysis ·  Ultrasonic Testing ·  Radar Inspection ·  Acoustic approached ·  etc. Sample Topics ·  Welding Technology ·  Material Science ·  Scale Effects ·  Rate Effects ·  Combined Stress ·  Analytical Studies ·  etc. Sample Topics  ·  Repair methodology ·  Joint details ·  Damping augmentation ·  Dynamic environment simulation ·  Electronic databases ·  Code modifications ·  etc. Specific I4R Initiative on Cracked Steel Joint Problem

  8. Research Needs in Structural Control • Use control to improve the seismic performance of existing structures, especially steel-frame buildings. • Develop more effective combinations of methods of control for design of new buildings. • Develop control methods for improving the seismic resistance of bridges. • Carry out experimental verification of integrated control and monitoring systems under realistic conditions. • Develop standardized benchmark tests for comparison purposes. • Carry out tests on full-scale buildings that have been provided with control systems. • Develop closer cooperation between research in structural control and research in smart materials and smart structures.

  9. Research Needs in Structural Control (cont) • Study protective control of critical facilities such as emergency response centers, emergency communication systems, fire and police response systems, etc., which must continue to function during earthquakes. • Expand the studies of structural control to include protection of such items as large computer facilities, hospital facilities including large medical equipment, electrical generation and distribution systems, TV and radio facilities, and other items that are important for emergency earthquake response. • Improve the competence of practicing engineers by preparing explanatory documents, giving seminars and short courses, etc.

  10. Short-Range Research Goals • Expanded application of passive control devices, • development of active control methods for moderate oscillations, • cost-effective control of existing structures, • health monitoring of civil infrastructure systems, and • experimental verification of large scale, if not full-scale, control applications.

  11. Long-Range Research Goals • Cost-effective methods of integrated control, • control systems for very large earthquakes and very strong winds, • post-earthquake damage detection, • development of appropriate design codes for structural control, and • collaborative international research.

  12. IASC Working Groups • Task Group on Benchmark Control Studies • Task Group on Structural Health Monitoring • Task Group on Codes for Structural Control

  13. US Task Group on Benchmark Structural Control Studies Summary of Activities

  14. Development of Task Groups • US Panel on Structural Control • 3 task groups established in collaboration with ASCE EMD’s Dynamics Committee in 1999 • Task Group on Benchmark Control Studies • Task Group on Structural Health Monitoring • Task Group on Codes for Structural Control • ASCE has furnished modest travel monies to support Task Group activities • Cooperation with parallel task groups in other regions

  15. TG on Benchmark Control Studies • Chaired by Prof. B.F. Spencer (UIUC) • Coordinating number of benchmark control studies in various stages of development • wind and seismic, building and bridge, etc. • Benchmark problems provide common structure and common evaluation methodologies, making direct comparison of control strategies feasible

  16. TG on Benchmark Control Studies • Past and current benchmark problems: • nonlinear seismic building benchmark (1999-2003) • wind-excited building benchmark (1999-2003) • seismically-excited cable-stayed bridge benchmark (phase I and phase II) (2000-2004) • controllable base isolated building benchmark (2003-?) • Future benchmarks in planning phase: • asymmetric wind building benchmark • typical highway bridge benchmark

  17. Nonlinear Seismic Building BenchmarkBuilding Models • 3-, 9- and 20-story buildings • 9-story building shown here • Designed for SAC Phase II Steel Project for LA

  18. Wind-Excited Tall Building BenchmarkBuilding Model • 76-story building • Office tower proposed for Melbourne, Australia • 0.16 Hznaturalfreq.,1%damping

  19. Cable-Stayed Bridge Seismic BenchmarkIntroduction • by SJ Dyke, LA Bergman, G Turan, J Caicedo • Available at http://wusceel.cive.wustl.edu/quake/bridgebenchmark/index.htm • MATLAB-based code to simulate response • Based on real bridge over Mississippi river (to be completed in 2003)

  20. Bill Emerson Memorial BridgeCape Girardeau, MOAugust 2003 Cable-Stayed Bridge Seismic Benchmark Bridge Model • 3-D FEM (599 nodes, 185 beam elements, 128 cable elements) • Linear model about the deformed position under static loads

  21. Cable-Stayed Bridge Seismic Benchmark Simulation • Simulink model to simulate response: • participantsspecify typeand locationof controldevices andsensors

  22. Cable-Stayed Bridge Seismic Benchmark Sample Control System Provided • Sample active control system provided: • Accelerometers • Hydraulic actuators

  23. Controlled Base Isolation BuildingIntroduction • by S Narasimhan, S Nagarajaiah, EA Johnson, H Gavin • Available at http://www.ruf.rice.edu/~nagaraja/baseisolationbenchmark.htm • MATLAB-based model to simulate response • Allows participants to design passive, active semiactive and hybrid isolation systems

  24. Controlled Base Isolation BuildingBuilding Model • Eight story, L-shaped steelbraced frame building • Similar to existing LA bldngs

  25. Controlled Base Isolation BuildingBuilding Model • FEM model • Superstructureassumed linear • Floors rigidin-plane

  26. Controlled Base Isolation BuildingProblem Definition • Control devices in isolation-layer only • Baseline isolation is linear, LRB or FPB • Nonlinear bearings modeled with 2-D Bouc-Wen hysteretic model • Nominal model: 2.5 s FPB with 10% friction coeff. • Evaluation measures include • superstructure responses (drifts, accels) • shear forces (base and foundation) • control device forces

  27. Controlled Base Isolation BuildingStatus • Problem definition first presented 3WCSC (Como, 2001); finalized version presented at EM2003 • Participant presentations expected at 4IWSC (NY, 2004) • Possibilities of a Journal special issue under investigation

  28. US Task Group onStructural Health Monitoring Summary of Activities

  29. Development of Task Groups • US Panel on Structural Control • 3 task groups established in collaboration with ASCE EMD’s Dynamics Committee in 1999 • Task Group on Benchmark Control Studies • Task Group on Structural Health Monitoring • Task Group on Codes for Structural Control • ASCE has furnished modest travel monies to support Task Group activities • Cooperation with parallel task groups in other regions

  30. TG on Structural Health Monitoring • Chaired by • Prof. Jim Beck (Caltech), 1999–2001 • Prof. Dennis Bernal (Northeastern), 2001–2003 • Prof. Erik Johnson (USC), 2003–present • Many SHM techniques exist • Benchmark studies, coordinated by the Task Group, provide mechanisms for comparing SHM strategies on a common problem • http://wusceel.cive.wustl.edu/asce.shm/

  31. Structural Health Monitoring Benchmarks • Several phases of a benchmark study in SHM have been defined by the task group • phase 1 simulated data • phase 2 simulated data • phase 2 experimental data • Based on model structure at U. of British Columbia Photo courtesy Prof. Carlos Ventura, UBC

  32. SHM BenchmarksPhase 1 Simulated Data • 12DOF identification model • Data generated with • 12DOF FEM model • ID model can completelycharacterize response • 120DOF FEM model • ID model cannot exactlycapture response model • thus, model error is important(as it is in the real world) • by Johnson (USC), Lam Katafygiotis, Beck

  33. SHM BenchmarksPhase 1 Simulated Data • Six cases • different excitation models • known vs. unknown excitation • 12DOF vs. 120DOF data generation models • Six damage patterns • generated by eliminating or reducing stiffness in one or more braces • 5th damage case involves loosened floor beam • MATLAB command line or GUI tool to select options and generate simulated response

  34. SHM BenchmarksPhase 1 Simulated Data • First results presented at EM2000 • Special issue of ASCE J. of Engineering Mechanics (Jan. 2004) • Benchmark problem definition paper • ID/damage detection algorithms using • Bayesian approaches • ERA • Wavelets • Subspace methodologies • etc.

  35. SHM BenchmarksPhase 2 Simulated Data • Same structure, but add more realism: • improved modeling error • modest damage with simple spatial distribution • brace and connection damage • Uses two “baseline” structures: fully braced and fully unbraced • Results presented at 3IWSC (Paris, 2002)

  36. SHM BenchmarksPhase 2e Simulated Data • extended version of Phase 2 • includes some “blind” tests where participants do not know the damage location or severity • Results presented at IMAC-XXI (Orlando, 2002)

  37. SHM BenchmarksPhase 2 Experimental Data • Same structure, but actual experiment • Data taken in numerous configurations4–7 August 2002, U of British Columbia • Damage simulated by removing bracing or loosening bolts • Full data sets and video describing the methodology is on the Task Group web sitehttp://wusceel.cive.wustl.edu/asce.shm/experim_phase_2.htm

  38. SHM BenchmarksCurrent/Future Developments • Several possible benchmarks are under investigation • typical highway overpass bridge • long-span bridge (cable-stayed or suspension) • For more info: • http://wusceel.cive.wustl.edu/asce.shm/ • or e-mail Prof. Erik Johnson JohnsonE@usc.edu

  39. Fourth International Workshopon Structural Control (4IWSC) Organized by • US Panel on Structural Control • IASC Columbia University New York, NY, USA Thursday-Friday, 10-11 June 2004

  40. Purpose of 4IWSC To review progress, promote research cooperation, and make recommendations for further research in the general field of active/hybrid vibration control and monitoring of civil infrastructure systems under the actions of earthquakes, wind, and extreme loads.

  41. Working Group Topics of 4IWSC • Building and Bridge Control, (2) Structural Health Monitoring, (3) Research Needs in Structural Control (involving adaptive materials, innovative sensing hardware, wireless technology, and novel actuators), and (4) International Collaboration involving recent national and multinational collaborative initiatives in North America, Asia and Europe.

  42. 4IWSC Agenda, Thursday 10 June 2004 7:00-8:00 Breakfast 8:00-8:30 Registration 8:30-8:45 Welcoming remarks 8:45-12:00 about 2.5 hours Panel technical reports from USA Panel technical reports from Japan Panel technical reports from Europe Panel technical reports from China Panel technical reports from Korea USA NEES and International Collaborative Efforts Japan Miki Shaker Collaborative Efforts European Testing Facilities Collaborative Efforts 12:00-1:30 lunch 1:30-5:00 [3 hours net including 30 min break] break participants into Working Groups WG1 Benchmark Problems in Control [buildings, bridges] WG2 Benchmark Problems in Monitoring [sensors, methodologies, models] WG3 International Collaboration Involving NEES, Miki shaker, Europe, etc 6:30-10:00 dinner boat-cruise around Manhattan

  43. 4IWSC Agenda, Friday 11 June 2004 8:00-10:30 Special Session on “Distributed Sensing for Structural Systems in the USA”  Overview of State-of-the-Art in “Sensor Nets”  State-of-the-Art in Wireless Sensing  NEES Nodes Sensor Capabilities and NEESgrid Capabilities  High-Accuracy GPS-based Relative Position Dynamic Sensing  Overview of State-of-the-Art in Model-Based Simulation & the Interface with Sensing Data 10:30-11:00 coffee break 10:45-12:00 Research Needs in Structural Control and Monitoring Areas (smart materials, innovative sensing hardware, wireless technology, semi-active actuators, simulation, etc) 12:00-1:30 Lunch 1:30-2:15 WG summary reports (each about 15 min with discussion) 2:15 - 3:00 pm General discussion 3:00 pm Adjourn Further details regarding the 4IWSC program, registration, housing information and paper format can be obtained from: http://www.civil.columbia.edu/4IWSC.

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