FIELD INSTRUMENTATION AND LIVE LOAD TESTING TO EVALUATE BEHAVIORS OF THREE ...

127 Pages·2004·3.03 MB·English

FIELD INSTRUMENTATION AND LIVE LOAD TESTING TO EVALUATE
BEHAVIORS OF THREE REINFORCED CONCRETE BRIDGE DECKS

by

Peter James Smolenski

A thesis submitted in partial fulfillment
of the requirements for the degree

of

Master of Science

in

Mechanical Engineering

MONTANA STATE UNIVERSITY
Bozeman, Montana
May 2004
© COPYRIGHT

by

Peter James Smolenski

2004

All Rights Reserved
ii

APPROVAL

of a thesis submitted by

Peter James Smolenski

This thesis has been read by each member of the thesis committee and has been
found to be satisfactory regarding content, English usage, format, citations, bibliographic
style, and consistency, and is ready for submission to the College of Graduate Studies.

Dr. Jerry Stephens

Dr. Douglas Cairns

Approved for the Department of Mechanical Engineering

Dr. Vic Cundy

Approved for the College of Graduate Studies

Dr. Bruce McLeod
iii

STATEMENT OF PERMISSION TO USE

In presenting this thesis in partial fulfillment of the requirements for a master’s
degree at Montana State University, I agree that the Library shall make it available to
borrowers under rules of the Library.
If I have indicated my intention to copyright this thesis by including a copyright
notice page, copying is allowable only for scholarly purposes, consistent with “fair use”
as prescribed in the U.S. Copyright Law. Requests for permission for extended quotation
from or reproduction of this thesis in whole or in parts may be granted only by the
copyright holder.

Peter James Smolenski
May 17, 2004
iv
ACKNOWLEDGEMENTS

This thesis would never have been completed without the wealth of support offered
by so many people. First and foremost, I acknowledge God for the blessings of a good
mind and a good attitude, which have brought me to this point. He has blessed me with a
loving wife, Casey, who has stood by my side throughout these two years, and devoted
parents who have always encouraged me to do my personal best and loved me regardless
of the outcome.
I extend my thanks to Jerry Stephens and Eli Cuelho for their patience, guidance,
encouragement and friendship throughout the Saco Bridge Project. None of this would
be possible without their expertise or their oversight. Each of them has encouraged me
toward excellence and bestowed gracious acknowledgements for a job well done. I
would also like to thank Jeff Johnson for the intelligence, hard work, and quick wit he has
brought to the many hours we’ve spent together on this project.
My gratitude is also extended to the Western Transportation Institute for funding my
research through a graduate fellowship and offering me the opportunity to learn and grow
in ways I might never have imagined.
v

TABLE OF CONTENTS
1. INTRODUCTION .........................................................................................................1
2. LITERATURE REVIEW ..............................................................................................4
BRIDGE DECK DESIGN CONSIDERATIONS ...................................................................... 5
LIVE LOAD TESTING OF BRIDGES .................................................................................. 9
3. DESCRIPTION OF BRIDGES ...................................................................................12
4. INSTRUMENTATION ...............................................................................................16
GENERAL LAYOUT....................................................................................................... 16
Position-Referencing Nomenclature..................................................................... 19
SENSORS ...................................................................................................................... 21
Vibrating Wire Strain Gages................................................................................. 21
Concrete Embedment Strain Gages ...................................................................... 23
Reinforcement Gages............................................................................................ 24
TM
BDI Intelliducers ............................................................................................... 27
DATA ACQUISITION SYSTEM........................................................................................ 29
Data Acquisition Unit ........................................................................................... 30
Multiplexers .......................................................................................................... 31
Communication and Power................................................................................... 32
Supporting Circuitry ............................................................................................. 33
Long-Term Monitoring Arrangement................................................................... 41
Live Load Testing Arrangement........................................................................... 42
5. LIVE LOAD TESTING...............................................................................................45
TEST VEHICLES............................................................................................................ 46
TESTING PROCEDURE................................................................................................... 48
Live Load Testing Regimen.................................................................................. 48
Data Processing..................................................................................................... 52
6. RESULTS AND OBSERVATIONS ...........................................................................53
OBJECTIVES ................................................................................................................. 53
GENERAL BEHAVIORS.................................................................................................. 54
DECK CRACKING AND AXIAL STRAIN ANALYSIS......................................................... 61
Deck Neutral Axis Position .................................................................................. 65
Deck Cracking Analysis ....................................................................................... 75
Axial Force Analysis............................................................................................. 79
Conclusions........................................................................................................... 86
DECK INTEGRITY OVER GIRDERS ................................................................................ 87
vi

TABLE OF CONTENTS
Deck Stiffness ....................................................................................................... 94
EVALUATION OF LINEAR-ELASTIC BEHAVIOR ............................................................. 98
REVIEW OF ANALYSIS OBSERVATIONS ...................................................................... 105
7. SUMMARY, CONCLUSIONS, AND RECOMMENDATIONS.............................107
SUMMARY.................................................................................................................. 107
CONCLUSIONS............................................................................................................ 109
RECOMMENDATIONS FOR FUTURE RESEARCH ........................................................... 110
8. REFERENCES CITED..............................................................................................113
vii

LIST OF TABLES

Figure Page
1. Average compressive strengths of deck concretes.................................................14
2. Actual neutral axis heights – Conventional deck...................................................71
3. Actual neutral axis heights – Empirical deck ........................................................72
4. Actual neutral axis heights – HPC deck ................................................................72
5. Hypothetical bending neutral axis locations at various cracking levels
under positive moment...........................................................................................75
6. Values of φ at Gage Location D-4 .........................................................................78
7. Actual neutral axis heights at Gage Location D-4 .................................................78
8. Calculated axial strains – Conventional deck ........................................................81
9. Calculated axial strains – Empirical deck..............................................................82
10. Calculated axial strains – HPC deck......................................................................82
11. Values of φ at 40m during ST-U test .....................................................................95
12. Summary of calculated transverse stiffness for each deck ....................................96
13. GDFs for longitudinal midspan, worst case for exterior girder .............................98
14. Values of φ (in degrees) at Gage Location D-4 ...................................................102
viii

LIST OF FIGURES

Figure Page
1. Reported results sample (Stallings and Porter 2002).............................................11
2. Elevation view of the three Saco bridges (typical) ................................................12
3. Partial cross-section view of the superstructure of the Saco bridges
(typical) ..................................................................................................................13
4. General positioning of longitudinal deck gages (plan view) .................................18
5. General positioning of transverse deck gages (plan view) ....................................19
6. General positioning of BDI gages on the bottom of girders (plan view)...............19
7. Gage reference numbering system.........................................................................20
8. Vibrating wire strain gage (VCE-4200) installation; Inset: dimensions................22
9. Concrete Embedment stain gage (EGP-5-350) installation; Inset:
dimensions .............................................................................................................24
10. Bonded foil resistance strain gage (CEA-06-250UN-350; not to scale)................26
11. Strain gage bonded to the reinforcement before (top) and after
(bottom) environmental protection ........................................................................28
12. Intelliducer™ mounted on bottom of girder; Inset: Dimensions...........................28
13. Various components within a data acquisition enclosure ......................................29
14. Communication path during long-term monitoring...............................................33
15. Ideal Wheatstone Bridge circuit arrangement........................................................35
16. Wheatstone Bridge arrangements employed for Saco bridges ..............................36
17. Diagram of daughterboard configuration...............................................................38
18. Alternative circuit design for employing single-ended measurements..................39
19. Data acquisition layout – long-term monitoring arrangement...............................42
20. Data acquisition layout – live load testing arrangement ........................................43
ix

LIST OF FIGURES

Figure Page
21. Dimension and weights of the Sterling 3-axle dump truck (lengths in
meters)....................................................................................................................47
22. Dimension and weights of the Volvo 3-axle dump truck (lengths in
meters)....................................................................................................................47
23. Side view of the Sterling 3-axle dump truck .........................................................48
24. Photograph of lines used for truck positioning during live load testing ................49
25. Cross-section views of truck tire placement for live load tests .............................50
26. Depiction of expected global longitudinal behaviors ............................................55
27. Strain history - Conventional deck longitudinal Gage Location D-3
(ST-T test)..............................................................................................................56
28. Strain history - all three decks longitudinal Gage Location D-3 (ST-T
test).........................................................................................................................58
29. Strain history - Empirical deck longitudinal Gage Location F-1 (ST-T
test).........................................................................................................................60
30. Strain history - all three decks longitudinal Gage Location F-1 (ST-T
test).........................................................................................................................61
31. Transverse gages of interest (Gage Line D) ..........................................................65
32. Deck cross-section geometries with calculated bending neutral axes
and expected bending strain profiles (uncracked) .................................................67
33. Typical positive moment response (Gage Location D-4, ST-S test) .....................70
34. Determination of actual neutral axis height ...........................................................70
35. Distinction between 40m and 42m truck positions, relative to Gage
Line D ....................................................................................................................72
36. Representations of theoretical cracking scenarios .................................................76
37. Hypothetical partially-cracked cross-section argument.........................................77