UCSD, PCA & NEESUCSD, PCA & NEESBLIND PREDICTION CONTESTBLIND PREDICTION CONTEST

Introductory RemarksIntroductory Remarks

Robert Bachman, S.E.Convener

REBachman Consulting Structural Engineers

Test Facility and Test Structure Test Facility and Test Structure

7 Story full-scale building slice

Reinforced concrete structural wall

NEES Large High- Performance Outdoor Shake Table at UCSD’s Englekirk Structural Engineering Center

Outline of this SessionOutline 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

DESCRIPTION OF TEST DESCRIPTION OF TEST PROGRAM PROGRAM

Marios Panagiotou, JosMarios Panagiotou, Joséé I. Restrepo, I. Restrepo, Joel P. Conte and Robert EnglekirkJoel P. Conte and Robert Englekirk

Department of Structural EngineeringDepartment of Structural EngineeringUniversity of California, San DiegoUniversity of California, San Diego

Two-phase Project funded by the Englekirk Structural Engineering Center Board of Advisors

Yehuda Bock, SIO, Payload Project PartnerJ.E. Luco, SE UCSD, Payload Project Partner and

Advisor

Ozgur Ozcelik, Graduate StrudentBobak Moaveni, Graduate Student

The assistance of NEESinc, NEESit, NSF and of Paul Somerville (URS Corp.) are greatly appreciated

AcknowledgmentsAcknowledgments

Englekirk Board of AdvisorsEnglekirk Board of Advisors

ObjectiveObjective

Verify the seismic performance of medium rise reinforced concrete residential 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 buildingResidential, multi-wall structure

– Sc soils

– Site less than 2 km from B fault

– Sv = 55 in./sec.V = 0.29 W Base Shear

Displacement-based DesignDisplacement-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%

Displacement-based DesignDisplacement-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

Capacity DesignCapacity 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 (1st mode!)

Larger floor accelerations

Test StructureTest 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 Testing14 ft. 7 in. long T-wall

63’-

0”

21

m

Flange wall

PT wall

Gravity columns

http://nees.ucsd.edu/

Design Summary & DetailingDesign 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

Design Summary & DetailingDesign Summary & Detailing

Aimed at Construction optimization– 1 reinforcement curtain in the wall’s 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)

Test RegimeTest 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

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0t (sec)

ag

(g

)

Sf-vnuy-lgn

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0t (sec)

ag

(g

)

Sf-vnuy-tr

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0

t (sec)

ag

(g

)

Nor-whox-lgn

-1.0

-0.8

-0.6

-0.4

-0.20.0

0.2

0.4

0.6

0.8

1.0

0.0 5.0 10.0 15.0 20.0t (sec)

ag

(g

)

Nor-Sylmar-360

EQ1EQ1

EQ2EQ2

EQ4EQ4

EQ3EQ3

Time (sec)

Acc

eler

atio

n (

g)

0 20

Acceleration Response Acceleration Response SpectraSpectra

0.0

0.5

1.0

1.5

2.0

2.5

0.0 0.5 1.0 1.5 2.0 2.5 3.0T (sec)

Sa

(g)

WN2%gWN3%gWN5%gEQ1EQ2EQ3EQ4

=5%

Design spectra

SensorsSensors

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

EQ4:

Test EQ4Test EQ4PGA = 0.93gPGA = 0.93g

EQ4:

Building’s Response to Sylmar Building’s Response to Sylmar Earthquake EQEarthquake EQ44

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 1/20th 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

Data Curing & Archiving 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

http://nees.ucsd.edu/

BLIND PREDICTION CONTESTBLIND PREDICTION CONTESTScoring, Comparison of Predicted vs Scoring, Comparison of Predicted vs Measured Quantities and WinnersMeasured Quantities and Winners

Robert Bachman, S.E.Convener

REBachman Consulting Structural Engineers

Overview of ContestOverview 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 10th 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 15th

Winners notified by May 25th

Basic Contest RulesBasic 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.

Scoring Procedure - Mean Square root error index

Ai : measured (actual) response quantity

Pi : predicted response quantity

Interstory Residual Team i M i V i di ü i / g drift ratio drift ratio*

1 4 1 8 4

8

2 0 0 2 8

4

3 2 8 4 2

2

4 1 4 1 1

58 2 0

0

0

1

Team score

8

2

1

4

0

16

19

10

12

33

Total points

Interstory Residual Team i M i V i di drift ratio displacement

1 0.593 0.844 0.3771.228 0.514

0.294

2 0.684 0.984 0.656 1.920 0.494

0.445

3 0.653 0.492 0.454 1.923 0.585

0.584

4 0.656 0.576 0.823 1.298 0.629

5 0.574 0.696 1.096 3.173 0.633 0.799

0.604

a i

2

i i

i

A Pmsre

A

Entries / Computer PlatformsEntries / 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

Undergraduate EntriesUndergraduate Entries

Italy – Laura Quaglini

Advisor – Dr. Rui Pinho

University of PaviaUS – Michael Billings, Soyoon Lee and

Evan Peterman

Advisor – Prof. Ansgar Neuenhofer

Cal Poly San Luis Obispo

Researcher/Academic EntriesResearcher/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

Engineering Practitioner EntriesEngineering 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

Selected Comparison of Selected Measured Selected Comparison of Selected Measured versus Predicted Responses versus Predicted Responses

(Top 4 in Researcher/Academic and Engineer (Top 4 in Researcher/Academic and Engineer Practitioner Categories) Practitioner Categories)

Blind Prediction Results - EQ3 - Shear Force EnvelopeFirst 4 teams of each category

0

1

2

3

4

5

6

7

0 50 100 150 200 250 300 350

Shear Force (kips)

Flo

or

Measured

Blind Prediction Results - EQ3 - Total Acceleration Envelope First 4 teams of each category

0

1

2

3

4

5

6

7

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Total Acceleration (g)

Flo

or

Interstory Drift Ratio

Blind Prediction Results - EQ3 - Shear Force EnvelopeFirst 4 teams of each category

Flo

or

Measured

Blind Prediction Results - EQ4 - Interstory Drift Ratio EnvelopeFirst 4 teams of each category

Interstory Drift RatioF

loo

r

Blind Prediction Results - EQ4 - Relative Lateral Displacement Envelope - First 4 teams of each category

0

1

2

3

4

5

6

7

0 2 4 6 8 10 12 14 16 18Relative Lateral Displacement (in)

Flo

or

Measured

Blind Prediction Results - EQ4 - Interstory Drift Ratio EnvelopeFirst 4 teams of each category

1

2

3

4

5

6

7

0.000 0.005 0.010 0.015 0.020 0.025 0.030Interstory Drift Ratio

Flo

or

Measured

Key FindingKey Finding

The M Factor

And the Winners Are –And the Winners Are –Drum Roll Please !Drum Roll Please !

Undergraduate Team WinnerUndergraduate Team Winner  

Researcher/Academic Team winner Researcher/Academic Team winner

and Engineer Practitioner winnerand Engineer Practitioner winner

Cal Poly San Luis Obispo  represented by Michael Cal Poly San Luis Obispo  represented by Michael

BillingsBillings

University of Ljubljana, Slovenia University of Ljubljana, Slovenia

represented by Matej Fischingerrepresented by Matej Fischinger

Mahmoud Hachem of Mahmoud Hachem of Wiss, Janney, Elstner, Emeryville, CaliforniaWiss, Janney, Elstner, Emeryville, California