Wakota Bridge Thermal Monitoring Program Part II: Data Analysis and Model Comparison Arturo E. Schultz, Principal Investigator Department of Civil Engineering University of Minnesota May 2013 Research Project Final Report 2013-12 To request this document in an alternative format, please contact the Affirmative Action Office at 651-366-4723 or 1-800-657-3774 (Greater Minnesota); 711 or 1-800-627-3529 (Minnesota Relay). You may also send an e-mail to [email protected]. (Please request at least one week in advance). Technical Report Documentation Page 1. Report No. 2. 3. Recipients Accession No. MN/RC 2013-12 4. Title and Subtitle 5. Report Date Wakota Bridge Thermal Monitoring Program May 2013 Part II: Data Analysis and Model Comparison 6. 7. Author(s) 8. Performing Organization Report No. Krista M. Morris and Arturo E. Schultz 9. Performing Organization Name and Address 10. Project/Task/Work Unit No. Department of Civil Engineering CTS Project #2010011 University of Minnesota 11. Contract (C) or Grant (G) No. 500 Pillsbury Drive SE Minneapolis, MN 55455 (C) 89261 (WO) 145 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Minnesota Department of Transportation Final Report Research Services 14. Sponsoring Agency Code 395 John Ireland Boulevard, MS 330 St. Paul, MN 55155 15. Supplementary Notes http://www.lrrb.org/pdf/201312.pdf 16. Abstract (Limit: 250 words) In this work, a common refined design method is evaluated with respect to a recently constructed bridge. Two finite element models of the Wakota Bridge in South St. Paul, Minnesota were produced using a design level program (SAP2000). These models were analyzed and their results compared to the data collected from the bridge. The second half of this study concerned the comparison of the collected field data with the values produced by evaluating the design-level finite element models previously created in Phase I of the project, and calibrating these models to provide an accurate prediction of the future behavior of the bridge. This was done by calculating changes in axial force and moment from strain data collected from the Wakota Bridge and changing various parameters within the design level model (DLM) in order to calibrate the models to the field data. The model using the refined design method was shown to correlate to the superstructure field data to within 2 percent, while between 13 percent and 35 percent correlation was seen between the model deploying the gross section method and the field data. The pier behavior predicted by the two models showed much less correlation to the field data. After calibration, it was possible to predict the general trend of the pier behavior, but the values of changes in moment did not correspond to the field data. This was especially true in Pier 4. Further consideration of the model parameters is necessary to fully calibrate the models. The two temperature application methods (Procedure A and B in the AASHTO LRFD) were also compared. The internal concrete temperature ranges measured in the field were much closer to the range specified in Procedure A. 17. Document Analysis/Descriptors 18. Availability Statement Temperature, Thermal stresses, Concrete, Bridge piers, Finite No restrictions. Document available from: element method National Technical Information Services, Alexandria, Virginia 22312 19. Security Class (this report) 20. Security Class (this page) 21. No. of Pages 22. Price Unclassified Unclassified 167 Wakota Bridge Thermal Monitoring Program Part II: Data Analysis and Model Comparison Final Report Prepared by: Krista M. Morris Arturo E. Schultz Department of Civil Engineering University of Minnesota May 2013 Published by: Minnesota Department of Transportation Research Services 395 John Ireland Boulevard, MS 330 St. Paul, Minnesota 55155 This report documents the results of research conducted by the authors and does not necessarily represent the views or policies of the Minnesota Department of Transportation or the University of Minnesota. This report does not contain a standard or specified technique. The authors, the Minnesota Department of Transportation, and the University of Minnesota do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to this report. Acknowledgments The authors would like to thank the Minneosta Department of Transportation for funding this project. The authors would also like to thank the Technical Advisory Panel (TAP) members for their help and guidance during the development of this report: Dave Dahlberg, Arielle Ehrlich, Shirlee Sherkow, Paul Stenberg, Jihshya Lin, and Dustin Thomas. Finally, the authors would like to thank Paul Bergson, Rachel Gaulke, Ben Dymond, Andrew Gastineau, and others in the Department of Civil Engineering at the University of Minnesota for their assistance and advice. Table of Contents Chapter 1. Introduction ........................................................................................................... 1 1.1 Overview ......................................................................................................................... 1 1.2 Background ..................................................................................................................... 2 1.3 Scope of Work ................................................................................................................ 2 Chapter 2. Literature Review ................................................................................................. 4 2.1 Modeling Cracked Concrete Sections ............................................................................. 4 2.1.1 Common Refined Design Method ............................................................................... 4 2.1.2 Gross Section Method ................................................................................................. 5 2.2 Design for Thermal Effects ............................................................................................. 5 2.2.1 Uniform Temperature ................................................................................................. 6 2.2.2 Minnesota Requirements ............................................................................................. 8 2.3 Summary of Phase 1 ....................................................................................................... 9 2.3.1 Research Level Model ................................................................................................. 9 2.3.2 Design Level Model .................................................................................................. 10 Chapter 3. Data Collection .................................................................................................... 14 3.1 Overview ....................................................................................................................... 14 3.2 Data Collection Issues ................................................................................................... 21 3.2.1 Lack of Accessibility ................................................................................................. 21 3.2.2 Technical Malfunctions ............................................................................................. 21 3.2.3 Damaged Gauges ...................................................................................................... 22 3.3 Collection Time Interval ............................................................................................... 22 3.4 Preliminary Strain Data Processing .............................................................................. 24 3.4.1 Strain and Temperature Along Blade Width ............................................................. 25 3.4.2 Strain and Temperature Data Along Blade Height .................................................. 27 3.4.3 Strain and Temperature Data Along Blade Depth ................................................... 28 3.4.4 Strain and Temperature Data Across Span Sections ................................................ 30 3.5 Linear String Potentiometer Data ................................................................................. 31 Chapter 4. Data Analysis ....................................................................................................... 33 4.1 Overview ....................................................................................................................... 33 4.2 Secondary Data Analysis .............................................................................................. 33 4.2.1 Batch Gauge Factors ................................................................................................ 33 4.2.2 Initial Reference Values ............................................................................................ 34 4.2.3 Age of Bridge Elements ............................................................................................. 35 4.3 Calculation of Stresses .................................................................................................. 36 4.3.1 Concrete Material Properties ................................................................................... 36 4.3.2 Calculation of Changes in Stress .............................................................................. 37 4.3.3 Creep and Shrinkage................................................................................................. 38 4.4