New Rating Methods for Pin and Hanger Assemblies in Steel Bridges

184 Pages·2017·3.68 MB·English

AN ABSTRACT OF THE THESIS OF

Jacob R. Montgomery for the degree of Master of Science in Civil Engineering presented
on December 18, 2017

Title: New Rating Methods for Pin and Hanger Assemblies in Steel Bridges

Abstract approved: ______________________________________________________
Christopher C. Higgins

Pin and hanger assemblies are a common type of connection used in past
engineering practice for steel girder bridges. The connection consists of pins, hanger
plates, and girder ends. The connection detail was used widely between 1930 and 1980.
The connections are considered fracture critical and nonredundant because connection
failure can lead to collapse of the bridge. One instance of such a failure was the 1983
collapse of the Mianus River Bridge in Connecticut. Despite the critical nature of these
connections, current specification-based rating methods lack clarity for evaluation of
existing bridges. Additionally, inconsistencies exist between different methodologies
used in bridge rating and design. In this thesis a literature review is conducted to identify
the available knowledge and experimental data for the elements that comprise pin and
hanger connections. Relevant past experimental data are only identified for the hangers
plates. The experimental data identified for hanger plates are compared against in-service
hangers and found to be of smaller scale but to have similar proportions. The data are
used to check the sufficiency of existing evaluation methods and new resistance factors
are calibrated for prediction methods consistent with LRFR methods. Recommendations
are made in the form of specification changes to improve rating methods for hanger
plates and knowledge gaps for the remaining connection components are discussed.
©Copyright by Jacob R. Montgomery
December 18, 2017
All Rights Reserved
New Rating Methods for Pin and Hanger Assemblies in Steel Bridges

by
Jacob R. Montgomery

A THESIS

submitted to

Oregon State University

in partial fulfillment of
the requirements for the
degree of

Master of Science

Presented December 18, 2017
Commencement June 2018
Master of Science thesis of Jacob R. Montgomery presented on December 18, 2017

APPROVED:

Major Professor, representing Civil Engineering

Head of the School of Civil and Construction Engineering

Dean of the Graduate School

I understand that my thesis will become part of the permanent collection of Oregon State
University libraries. My signature below authorizes release of my thesis to any reader
upon request.

Jacob R. Montgomery, Author
ACKNOWLEDGEMENTS

Firstly, I would like to thank Caltrans for funding this project. Thank you, Dr.
Higgins, for giving me the opportunity to work on this project and realize my academic
goals. Thank you, Dr. Liu, for your generous open-door policy and thoughtful insight. I
would like to extend my gratitude to both Dr. Higgins and Dr. Liu for their guidance
throughout this project extensive time commitment. I would like to thank Pavan Patel for
his early work on the investigating and implementing the calibration process. I would like
to thank my parents for believing in me and investing so much in my future. Finally, I
would like to thank my wife, Adrienne, for encouraging me to go back to school and
being supportive and understanding of my sometimes-unfortunate schedule.
TABLE OF CONTENTS
Page
Chapter 1 – Introduction ......................................................................................................1 
1.1 Background ............................................................................................................... 1 
1.2 Objectives .................................................................................................................. 4 
1.3 Organization .............................................................................................................. 5 
Chapter 2 – Literature Review .............................................................................................6 
2.1 Introduction ............................................................................................................... 6 
2.2 Design and Rating Specification Review .................................................................. 7 
2.2.1 Standard Specifications ...................................................................................... 7 
2.2.2 AASHTO Rating Methods ............................................................................... 19 
2.2.3 Alternate Rating Methods ................................................................................. 33 
2.3 Field Performance and Inspection ........................................................................... 43 
2.3.1 Askeland, et al. (1987) ...................................................................................... 43 
2.3.2 Kulicki et al. (1990) .......................................................................................... 45 
2.3.3 South et al. (1992) ............................................................................................ 46 
2.3.4 Miller and Chaney (1994) ................................................................................ 47 
2.3.5 Finch et al. (1994)............................................................................................. 47 
2.3.6 Juntunen (1998) ................................................................................................ 48 
2.3.7 Jansson (2008) .................................................................................................. 50 
2.3.8 Moore et al. (2004) ........................................................................................... 51 
2.3.9 Discussion ......................................................................................................... 52
TABLE OF CONTENTS (Continued)
Page
2.4 Experimental Studies ............................................................................................... 53 
2.4.1 Hanger Plates .................................................................................................... 53 
2.4.2 Pins ................................................................................................................... 73 
2.4.3 Beam Ends ........................................................................................................ 79 
2.5 Materials .................................................................................................................. 87 
2.5.1 AISC Design Guide 15 ..................................................................................... 88 
2.5.2 Mechanical and Corrosion Wear of Sliding Interface ...................................... 88 
2.6 Literature Review Conclusion ................................................................................. 91 
Chapter 3 – Analysis of Hanger Plate Ultimate Strength Predictions ...............................94 
3.1 Introduction ............................................................................................................. 94 
3.2 Data Review ............................................................................................................ 94 
3.3 Caltrans Inventory ................................................................................................... 95 
3.4 Failure Modes ........................................................................................................ 101 
3.5 Review of Caltrans’ Rating Methods .................................................................... 103 
3.5.1 Caltrans LFR Method ..................................................................................... 104 
3.5.2 Caltrans LRFR Method .................................................................................. 107 
3.6 Analysis by Failure Mode ..................................................................................... 110 
3.6.1 Failure Behind the Pin .................................................................................... 110 
3.6.2 Fracture on Net Section .................................................................................. 115 
3.6.3 Dishing ........................................................................................................... 118 
3.6.4 Dishing Proportional Limit............................................................................. 120 
3.7 Discussion ............................................................................................................. 124
TABLE OF CONTENTS (Continued)
Page
Chapter 4 – Calibration of Resistance Factors for LRFR ................................................126 
4.1 Introduction ........................................................................................................... 126 
4.2 Load and Resistance as Random Variables ........................................................... 126 
4.3 Load Variability .................................................................................................... 128 
4.3.1 Load Statistical Properties .............................................................................. 128 
4.3.2 Load Mean and Standard Deviation ............................................................... 130 
4.4 Resistance Statistical Properties ............................................................................ 133 
4.5 Reliability Index .................................................................................................... 135 
4.6 Monte Carlo Simulation ........................................................................................ 138 
4.7 Calibration Results ................................................................................................ 141 
Chapter 5 – Conclusion and Recommendations ..............................................................145 
5.1 Summary and Conclusions .................................................................................... 145 
5.2 Recommendations and Future Work ..................................................................... 148 
References ........................................................................................................................150 
Appendices .......................................................................................................................155 
Appendix A – Historic Steel Specification (Brockenbrough, 2002) ........................... 156 
Appendix B – Example Calibration Simulation .......................................................... 162 
Appendix C – Recommended AASHTO MBE Revisions .......................................... 165