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Learning from Earthquakes Program: Field Investigations and Collaborative Research

EERI's Learning from Earthquakes Program, funded by the NSF, sends multidisciplinary teams to investigate earthquake and tsunami effects, assess damages, and plan follow-up research. Collaborators include researchers from various fields, and the program focuses on rapid damage surveys, instrumentation preparations, and building assessments in earthquake-affected areas like Chile and the US.

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Learning from Earthquakes Program: Field Investigations and Collaborative Research

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  1. Bob Nigbor NEES@UCLA

  2. In 1973, EERI formally initiated the Learning from Earthquakes (LFE) Program. This program, funded by the U.S. National Science Foundation, sends out multi- disciplinary teams of researchers (e.g., earth scientists, engineers, social scientists) into the field to investigate and to learn from the damaging effects of earthquakes and tsunamis. The reconnaissance team makes a rapid, general damage survey of the affected area, documents initial important observations from the tsunami and/or earthquake, and assesses the need for follow-up areas of research.

  3. Project Collaborators and Contributors: John Wallace, PI (UCLA) Bob Nigbor co-PI (UCLA) Anne Lemnitzer (Cal State Fullerton) Alberto Salamanca (NEES@UCLA) Derek Skolnik (Kinemetrics) Leonardo Massone (Univ. of Chile, Santiago) Juan Carlos de la Llerra (Catholic University of Chile, Santiago) + the EERI Reconnaissance Team

  4. Preparation of Instrumentation provided by NEES@UCLA

  5.  Two 24-channel systems: › 4 Q330s › Ethernet LAN › GPS timing › Netbook running Rockhound, continuous and triggered recording › Accelerometers › Displacement sensors (LVDTs) › Battery power  Packing › Generic suitcases › Letters with lots of logos & stamps

  6. Buildings selected based on: - Access and permission -Typical design layouts representative for Chile and the US -Local collaborator for building selection: Juan Carlos de la Llerra Ambient Vibration 2 Aftershocks Ambient Vibration 30 Aftershocks Ambient Vibration 4 Aftershocks

  7. Building B: -10 story RC residential building - Structural system: Shear Walls -Post Earthquake damage: I. Shear wall failure, II. Column buckling, III. Extensive non-structural failure, IV. slab bending & concrete spalling

  8. Observed Damage in the 10 story shear wall building: Repetitive Damage at the -1 level (Parking level): Wall-Slab intersections

  9. EW Acceleration NS Acceleration 20 20 Roof (cm/s2) Roof (cm/s2) 0 0 Roof -20 -20 40 60 80 100 120 40 60 80 100 120 20 20 9th (cm/s2) 9th (cm/s2) 9th 0 0 -20 -20 40 60 80 100 120 40 60 80 100 120 20 20 2nd (cm/s2) 2nd (cm/s2) 2nd 0 0 -20 -20 40 60 80 100 120 40 60 80 100 120 20 20 Grnd (cm/s2) Grnd (cm/s2) 0 0 -1 st -20 -20 40 60 80 100 120 40 60 80 100 120

  10. EW Displacement NS Displacement 2 2 Roof (mm) Roof (mm) 0 0 Roof -2 -2 40 60 80 100 120 40 60 80 100 120 2 2 9th (mm) 9th (mm) 0 0 9th -2 -2 40 60 80 100 120 40 60 80 100 120 2 2 2nd (mm) 2nd (mm) 0 0 2nd -2 -2 40 60 80 100 120 40 60 80 100 120 2 2 Grnd (mm) Grnd (mm) 0 0 -1 st -2 -2 40 60 80 100 120 40 60 80 100 120

  11. 2.5 Roof 9th 2nd Ground 2 1.5 1 0.5 NS (mm) 0 -0.5 -1 -1.5 -2 -2.5 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 EW (mm)

  12. Figure 4: Shear-flexure interaction for a wall subject to lateral loading. (adapted from Massone and Wallace, 2004)

  13. 0.2 shear flexure 0.15 0.1 Wall top Disp (mm) 0.05 0 -0.05 -0.1 -0.15 -0.2 30 40 50 60 70 Time (s) 80 90 100 110 120 The rotation for flexure was taken at the base of the wall (so the top displacement is multiplied by the wall height), which is the largest value expected for flexure. If we assume that the flexure corresponds to a rotation at wall mid-height, the flexural component should be multiplied by 0.5.

  14.  Getting equipment in (luggage vs shipping, invitation letters, label equipment as non permanent)  Local collaboration is critical (building access, installation, translations)  GPS antenna location is critical  Ethernet cables have variable quality, bring your own plenum-rated & shielded  Trigger and recording needs optimization, consider continuous recording for few-day installations  Local student operation is possible but requires training & Skype

  15.  Reduced cabling or wireless  Simpler systems (Black Box) that can accompany the recon engineers and be deployed by non-experts

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