UCSD, PCA & NEES BLIND PREDICTION CONTEST

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

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

Acknowledgments
• 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 and of Paul
Somerville (URS Corp.) are greatly appreciated

Englekirk Board of Advisors

Objective
• 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
• 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
Los Angeles

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%

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 inelasticelastic
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 Design
• To guarantee the desired performance at the Lifeprevention
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

Test Structure
63’-0” 21 m
PT wall
Gravity
columns
Flange wall
Cantilever
web wall
• 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
• Phase 1 Testing:
12 ft. long rectangular wall
• Phase 2 Testing
14 ft. 7 in. long T-wall

Design Summary & Detailing
Web Wall Level 1
8” (204 mm)
12’-0” (3.6 m)
ρ l = 0.44% ρ t = 0.31% ρ v = 1.36%
Web Wall Level 2
6” (152 mm)
ρ l = 0.60% ρ t = 0.31% ρ v = 0

Design 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 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
ag (g)
ag (g)
Acceleration ag (g) (g)
ag (g)
1.0
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
Sf-vnuy-lgn
0.0 5.0 10.0 15.0 20.0
1.0
t (sec)
0.8
Sf-vnuy-tr
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
1.0
t (sec)
0.8
0.6
EQ3
Nor-w hox-lgn
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
EQ1
EQ2
-1.0
0.0 5.0 10.0 15.0 20.0
1.0
0.8
t (sec)
0.6
EQ4
Nor-Sylmar-360
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.00 5.0 10.0 15.0 20 20.0
t (sec)
Time (sec)

Acceleration Response Spectra
2.5
S a (g)
2.0
1.5
1.0
Design
spectra
WN2%g
WN3%g
WN5%g
EQ1
EQ2
EQ3
EQ4
ξ=5%
0.5
0.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0
T (sec)

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

EQ4:
Test EQ4
PGA = 0.93g

EQ4:

Building’s s Response to Sylmar
Earthquake EQ4
• 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

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

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

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

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.

Scoring Procedure - Mean Square root error index
Interstory
Residual
Team i M i V i d i drift ratio displacement
1 0.593 1.228 0.844 0.377 0.514 0.294
2 0.684 1.920 0.984 0.656 0.494 0.445
3 0.653 1.923 0.492 0.454 0.585 0.584
a i
( A − P)
msre
= ∑ ∑
Ai : measured (actual) response quantity
i
A
i
i
2
4 0.656 1.298 0.576 0.823 0.629
0.604
5 0.574 3.173 0.696 1.096 0.633 0.799
Pi : predicted response quantity
Team score
Interstory Residual
Team i M i V i d i ü i / g drift ratio drift ratio*
1 4 8 1 8 4 8
2 0 2 0 2 8 4
3 2 1 8 4 2 2
Total
points
33
16
19
4 1 4 4 1 1
1
12
5
8 0 2 0 0 0
10

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

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

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

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

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

7
6
Blind Prediction Results - EQ3 - Shear Force Envelope
First 4 teams of each category
Measured
5
Floor
4
3
2
1
0
0 50 100 150 200 250 300 350
Shear Force (kips)

7
6
Blind Prediction Results - EQ3 - Total Acceleration Envelope
First 4 teams of each category
Measured
5
Floor
4
3
2
1
0
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)

7
6
Blind Prediction Results - EQ4 - Relative Lateral Displacement
Envelope - First 4 teams of each category
Measured
5
Floor
4
3
2
1
0
0 2 4 6 8 10 12 14 16 18
Relative Lateral Displacement (in)

7
6
Blind Prediction Results - EQ4 - Interstory Drift Ratio Envelope
First 4 teams of each category
Measured
5
Floor
4
3
2
1
0.000 0.005 0.010 0.015 0.020 0.025 0.030
Interstory Drift Ratio

• The M Factor
Key Finding

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