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UCSD, PCA & NEES BLIND PREDICTION CONTEST Introductory Remarks Robert Bachman, S.E. Convener REBachman Consulting Structural Engineers.

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Presentation on theme: "UCSD, PCA & NEES BLIND PREDICTION CONTEST Introductory Remarks Robert Bachman, S.E. Convener REBachman Consulting Structural Engineers."— Presentation transcript:

1 UCSD, PCA & NEES BLIND PREDICTION CONTEST Introductory Remarks Robert Bachman, S.E. Convener REBachman Consulting Structural Engineers

2 Test Facility and Test Structure 7 Story full-scale building slice Reinforced concrete structural wall NEES Large High- Performance Outdoor Shake Table at UCSDs Englekirk Structural Engineering Center

3 Outline of this Session Description of Test Facility, Design of Test Structure and Testing Program and Discussion of Test Results Overview of Blind Prediction Contest, Entries and the computer platforms they used Comparison of Range of Predicted Values with Measured Announcement of Winners Presentation by Contest Winners of Approach Used

4 DESCRIPTION OF TEST PROGRAM Marios Panagiotou, José I. Restrepo, Joel P. Conte and Robert Englekirk Department of Structural Engineering University of California, San Diego

5 Two-phase Project funded by the Englekirk Structural Engineering Center Board of Advisors Yehuda Bock, SIO, Payload Project Partner J.E. Luco, SE UCSD, Payload Project Partner and Advisor Ozgur Ozcelik, Graduate Strudent Bobak Moaveni, Graduate Student The assistance of NEESinc, NEESit, NSF, Technical Staff at ESEC and of Paul Somerville (URS Corp.) are greatly appreciated Acknowledgments

6 Englekirk Board of Advisors

7 Objective Verify the seismic performance of medium rise reinforced concrete wall building designed for lateral forces that are significantly smaller than those currently specified in building codes in United States Los Angeles UBC 97: Seven story building Residential, multi-wall structure –S c soils –Site less than 2 km from B fault –S v = 55 in./sec. V = 0.29 W Base Shear

8 Displacement-based Design Two performance levels: Immediate occupancy in frequently occurring earthquakes Limited yielding (1% tensile strain maximum) Limiting interstory drift ratio Life-safety in rare earthquakes (10% in 50) Tensile strains less than 5% compressive strain less than 1%

9 Displacement-based Design Based on initial stiffness and an effective first mode mass Direct use of the Displacement Response Spectra for elastic response Considers the relationship between inelastic- elastic response of SDOF (Miranda – 90 percentile) Definition of curvature and displacement ductility –Strain limits for concrete and reinforcement –Foundation flexibility V = 0.15 W Base Shear

10 Capacity Design To guarantee the desired performance at the Life- prevention level Explicit selection of a mechanism of inelastic deformation Explicit recognition of effects caused higher modes of response Larger than forces obtained from DBD analysis (1 st mode!) Larger floor accelerations

11 Test Structure 7-story building slice with cantilever wall as the lateral force resisting system Tallest building structure ever tested on a shaketable Single axis of input ground motion in the plane of the wall Cantilever web wall Phase 1 Testing: 12 ft. long rectangular wall Phase 2 Testing 14 ft. 7 in. long T-wall 63-0 21 m Flange wall PT wall Gravity columns

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13 Design Summary & Detailing l = 0.44% t = 0.31% v = 1.36% Web Wall Level 1 12-0 (3.6 m) 8 (204 mm) 6 (152 mm) l = 0.60% t = 0.31% v = 0 Web Wall Level 2

14 Design Summary & Detailing Aimed at Construction optimization –1 reinforcement curtain in the walls web on level 1 –Well confined wall ends High-strength Baugrid electro-welded confinement reinforcement at wall ends –1 reinforcement curtain on levels 2-7 –Tunnel form construction –Concrete with specified compressive strength of f c = 4 ksi (28 MPa)

15 Test Regime Testing at the NEES@UCSD Large High-Performance Outdoor Shake Table between October 2005 and January 2006 Structure tested under increase intensity historical earthquake records and with low-intensity band-clipped white noise in between earthquake tests Time (sec) Acceleration (g) 0 20

16 Acceleration Response Spectra =5% Design spectra

17 Sensors 600+ sensors deployed on the building, shake table and surrounding soil –DC Coupled Accelerometers –Displacement transducers –Strain gauges –Load cells –Oil pressure transducers First time use of 50Hz, 3 mm resolution, real-time GPS displacement sensors 17 videos feeds streamed through NEEScentral

18 EQ4: Test EQ4 PGA = 0.93g

19 EQ4:

20 Buildings Response to Sylmar Earthquake EQ 4 Performance levels anticipated were met: –Cosmetic damage at the base of the wall –Reinforcement strains reached 2.7% –Peak roof-drift ratio was 2.1% –Residual crack widths less than 1/20 th of an inch –Negligible residual displacements (1/2 in. at the roof ) The building slice could perhaps not be immediately occupied but only required minimum repairs

21 Data Curing & Archiving Significant amount of data has been collected and is being reduced All data and metadata will be archived in the NEES Data Repository and will be made available to all NEES users and researchers

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23 BLIND PREDICTION CONTEST Scoring, Comparison of Predicted vs Measured Quantities and Winners Robert Bachman, S.E. Convener REBachman Consulting Structural Engineers

24 Overview of Contest Web site set up – included links to test structure data, test motions, contest rules, input sheet and questions/answers NEES email addresses set up for Q/A and entries Contest announced March 10 th via electronic communications (PCA, NEES, the NSF EQ Centers, EERI), Structural Engineers Associations – and personal communications Q & A posted periodically on web site Entries were due electronically May 15 th Winners notified by May 25 th

25 Basic Contest Rules Goal – predict responses by analysis - compare with measured 3 Categories of teams – Winner PCA Award of $ 2500 per team 1. Undergraduates 2. Researchers/Academics 3. Engineering Practitioners Predict responses for 4 levels of earthquakes – responses included displacements, drifts, shears, moments, accelerations throughout the structures and vertical strains near base. Entries judged by determining error in each type of response Lowest error awarded points. Sum points. Largest sum winner The entries were handled confidentially – folks at UCSD did not know who submitted what entries. Relative ranking confidential.

26 Scoring Procedure - Mean Square root error index A i : measured (actual) response quantity P i : predicted response quantity InterstoryResidual Team i M i V i d i ü i / g drift ratiodrift ratio* 1 4184 8 2 002 8 4 3 284 2 2 4 141 1 5 820 0 0 1 Team score 8 2 1 4 0 16 19 10 12 33 Total points InterstoryResidual Team i M i V i d i drift ratiodisplacement 1 0.5930.8440.377 1.228 0.514 0.294 2 0.6840.9840.656 1.920 0.494 0.445 3 0.6530.4920.454 1.923 0.585 0.584 4 0.6560.5760.823 1.298 0.629 5 0.5740.6961.096 3.173 0.633 0.799 0.604 a i

27 Entries / Computer Platforms 21 total entries/ 8 countries Undergraduates – 2 teams / 2 countries Countries – Italy and US Computer Platforms – Etabs and SeismoStruct Researchers/Academics – 11 teams / 8 countries Countries – Canada, France, Italy, Mexico, New Zealand, Slovenia, Taiwan, US Computer Platforms: Abaqus, Canny, Column, Fedeas Lab, Narc2004, OpenSees, Ruaumoko, Sap 2000 Engineering Practitioners – 8 teams / 2 countries Countries – New Zealand and US Computer Platforms: Adina, ANSR-II, Hand Calculator/code formulas, OpenSees, PC-ANSR, Ram Perform 3-D

28 Undergraduate Entries Italy – Laura Quaglini Advisor – Dr. Rui Pinho University of Pavia US – Michael Billings, Soyoon Lee and Evan Peterman Advisor – Prof. Ansgar Neuenhofer Cal Poly San Luis Obispo

29 Researcher/Academic Entries Canada – Alireza Ahmdina and Carlos Ventura France – Stephane Grane, Panagiotis Kotronis and Jacky Mazars Italy/US – Paolo Martinelli and Filip Filippou Mexico – Mario Rodriquez, Roque Sanchez and Miguel Torres New Zealand – Dion Marriot, Kam Yuen Yuen, Stefano Pampanin and Athol Carr Slovenia – Matej Fischinger, Peter Kante and Tatjana Isakovic Taiwan – Kuang-Yen Liu US/SUNY Buffalo – Methee Chiewanichakorn and Amjad Aref US/Univ of Washington – Blake Doekper, Laura Lowes and Dawn Lehman US/Univ of Missouri at KC – Kavitra Deshmukh, Ganesh Thiagarajan, Thomas Heausler US/Iowa State University – Jon Waugh and Sri Sritharan

30 Engineering Practitioner Entries Nikolay Doumbalski, MMI, Oakland, CA Rick Drake, JSDyer, Anaheim, CA Mahmoud Hachem, Emeryville, CA Jimin Huang, HDR Engr, Minneapolis, Minnesota Trevor Kelly, Holmes Consulting Group, New Zealand Bruce Maison, EBMUD, El Cerrito, CA David Nilles,PE. SE., Washougal, WA Jianxia Zhong, Y.L. Mo, Paul Jacob and Turel Gur mostly from MMI in Houston, Texas

31 Selected Comparison of Selected Measured versus Predicted Responses (Top 4 in Researcher/Academic and Engineer Practitioner Categories)

32 Measured

33

34

35

36 Key Finding The M Factor

37 And the Winners Are – Drum Roll Please ! Undergraduate Team Winner Undergraduate Team Winner Researcher/Academic Team winner and Engineer Practitioner winner Cal Poly San Luis Obispo represented by Michael Billings University of Ljubljana, Slovenia represented by Matej Fischinger Mahmoud Hachem of Wiss, Janney, Elstner, Emeryville, California


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