NIST–ATC BLIND PREDICTION CONTEST ON DEEP,

WIDE-FLANGE STRUCTURAL STEEL BEAM-COLUMNS

The National Institute of Standards and Technology (NIST) and the Applied Technology Council (ATC) invite the structural engineering community to participate in the prediction of the seismic response of three deep, wide-flange structural steel beam-columns.  These members were tested quasi-statically as part of a comprehensive research program funded by NIST at the Seismic Response Modification Device (SRMD) facility of the University of California, San Diego.

CONTENTS

Purpose and Background
Contest Rules
Timeline
Awards
Provided Information, Assumptions, References
Submittal Rules
Questions and Answers

PURPOSE AND BACKGROUND

The purpose of this contest is to assess the uncertainty in the predicted response of wide-flange structural steel beam-columns by predicting various response parameters beam-column test specimens of known dimensions, material properties, and loading protocols.

The contest is a component of the ongoing NIST-funded ATC‑106-1 project.  Since the project’s initiation in September 2015, 23 deep, slender wide-flange beam-column specimens have been tested at the Seismic Response Modification Device facility of the University of California, San Diego.  The overarching goal of the ATC-106-1 project is to determine the fundamental behavior of these structural members under constant or variable axial force loads.  The project is a continuation of the ATC-106 project that took place between 2013 and 2015 and tested 25 specimens at UC San Diego.

 

CONTEST RULES

  • Contestants may consist of individuals or teams.
  • An individual can only be involved in a single team.
  • If an individual is part of a team, the individual cannot enter the competition separately as an individual.
  • A company or a research institution may submit several predictions.
  • Contestants will submit a single entry of one of the following two categories:
    • Simple: This category is recommended for structural engineers and researchers using simple nonlinear models intending to capture the main response parameters.
    • Comprehensive: This category is recommended for structural engineers and researchers intending to model the test specimens to capture the full nonlinear cyclic response of the test specimens, and intending to predict overall and local response parameters.
  • There will be one winner for each of the two categories.
  • Although names and affiliations of participating teams will be recognized publicly, results will be presented anonymously except for those of the “winning” entries.
  • Questions about the blind prediction contest or details of the column specimens can be submitted This email address is being protected from spambots. You need JavaScript enabled to view it. until December 15, 2017. Questions and answers will be posted on the web site and will be updated weekly. For updates on questions and answers, please check this page or subscribe here.

TIMELINE

  Event   Date
  Submittals Due1   January 12, 2018
  Category Winners Notified2   January 26, 2018
  Category Winners Awarded3      April 10-13, 2018

 

 

 


1
  Contestants shall submit their final submittal spreadsheet on or before January 12, 2018 This email address is being protected from spambots. You need JavaScript enabled to view it.. An email acknowledging the submittal will be sent to each team.
2   Category winners will be notified by January 26, 2018 via email used for submittal.
3   Category winners will be awarded at the AISC Steel Conference (NASCC) taking place in Baltimore, Maryland on April 10-13, 2018.  One representative of each category winner will be invited to make a presentation on the techniques used (model and analysis) and challenges arising in the prediction, which resulted in a winning team.


AWARDS

Full registration to NASCC 2018 for one representative
from each category winner, as well as other prizes, sponsored by the AISC!
 
The winners will be recognized at the NASCC session
and highlighted in the ATC Newsletter.



PROVIDED INFORMATION, ASSUMPTIONS, REFERENCES

The blind prediction contest directory contains the following information:

  • Summary of contest rules
  • General information on specimens and loading protocol.
  • Material test results
  • Corrected loading protocol
  • Submission spreadsheets (see below for a detailed description)
  • The following references that summarize previous tests conducted under this program.
    • Ozkula, G., Harris, J. and Uang, C.M., 2017. Observations from Cyclic Tests on Deep, Wide-Flange Beam-Columns. Engineering Journal, 1, pp.45-59.
    • Ozkula, G., Harris, J. and Uang, C.M., Classifying Cyclic Buckling Modes of Steel Wide-Flange Columns under Cyclic Loading. In Structures Congress 2017, pp. 155-167.

Computational models can assume the column ends were fastened to rigid elements as data has been post-processed to remove the flexibility occurring at the column ends due to the deformation of tie-down rods and end plates.

SUBMITTAL RULES

The individual or team must use the contest submittal spreadsheet and input values as follows:

Category A. Simple–  Submit results using spreadsheet Simple_Entry.xls:

  • Questionnaire tab: Provide brief description of the method of analysis.
  • For Specimens A and B, tested under constant axial load:
    • Ratio Mmax / Mpc to two decimal places, where Mpc is the reduced plastic moment.
    • Lateral force in units of kip to one (1) decimal place versus drift ratio envelope, for various drift ratios specified.
    • Mode of primary nonlinear response.
  • For Specimen C, tested under variable axial load:
    • Ratio Mmax / Mpc to two (2) decimal places for two axial loads.
    • Positive lateral force in units of kip to one (1) decimal place versus drift ratio envelope, for various drift ratios and corresponding axial loads.
    • Negative lateral force in units of kip to one (1) decimal place versus drift ratio, for various drift ratios and corresponding axial loads.
    • Mode of primary nonlinear response.

Category B. Comprehensive – Submit results using spreadsheet Comprehensive_Entry.xls:

  • Questionnaire tab: Describe the method of analysis
  • For Specimens A and B, tested under constant axial load:
    • Ratio Mmax / Mpc to two decimal places.
    • Lateral force in units of kip to one (1) decimal place versus drift ratio envelope for the drift ratios specified.
    • Hysteretic energy in units of kip-in to zero (0) decimal places calculated between various drift ratios.
    • Column shortening in units of inches to two (2) decimal places calculated for various drift ratios.
    • Mode of primary nonlinear response.
  • For Specimen C, tested under variable axial load:
    • Ratio Mmax / Mpc to two (2) decimal places for two axial loads.
    • Positive lateral force in units of kip to one (1) decimal place versus drift ratio envelope for drift ratios and corresponding axial loads.
    • Negative lateral force in units of kip to one (1) decimal place versus drift ratio for the drift ratios and corresponding axial loads.
    • Hysteretic energy in units of kip-in to zero (0) decimal places calculated between the various drift ratios and corresponding axial loads.
    • Column shortening in units of inches to two (2) decimal places calculated for various drift ratios and corresponding axial loads.
    • Mode of primary nonlinear response.

QUESTIONS AND ANSWERS

For answers to questions regarding the blind prediction contest, please This email address is being protected from spambots. You need JavaScript enabled to view it.. Answers to questions are posted below. To remain current on Q&As, please refer back to this page often, or subscribe to updates here.

Question: Would it be possible to provide the chemical decomposition of the specimens’ steel materials?
Answer: The chemical properties of Specimens A, B, and C are provided in the table shown below and also uploaded as a pdf under the Test Specimen Information folder in the blind prediction contest directory.

Mill Certificate: Chemical Composition

Specimen
Designation
Column
Size
Chemical Composition (%)
C Si Mn P S Cu Ni Mo Cr Al V Nb Sn CE
A W30×148 0.17 0.15 0.104 0.013 0.011 0.23 0.08 0.02 0.12 0.002 0.056 0.001 0.013 0.4
B W14×82 0.08 0.2 0.2 0.02 0.032 0.34 0.11 0.022 0.18 0.003 0.001 0.021 0.01 0.29
C W18×130 0.07 0.23 1.3 0.015 0.025 0.32 0.11 0.03 0.15 - 0.04 0.001 0.01 0.36


Question: The submittal date on the announcement email listed January 22, 2017. Has the deadline passed for submittals?

Answer: We apologize for the mistake. The submittal deadline is January 12, 2018. Good luck!

Question: Regarding the units on the material test coupon C -- want to confirm that the units should be as listed in the data [in/in] and not as plotted [%], i.e. failure strains are on the order of 40%/25%, and not less than 1%.
Answer: The test data for all three specimens are correct; however, the horizontal axis for Specimen C tensile coupon test results was not labelled correctly.  A corrected file, Engineering Stress-Stress Data_rev1.xls, is now posted under Material Test Results in the blind prediction contest directory

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