INFLUENCE OF PIER NONLINEARITY, IMPACT ANGLE, AND COLUMN SHAPE ON PIER ...

81 Pages·2004·4.18 MB·English

INFLUENCE OF PIER NONLINEARITY, IMPACT ANGLE, AND COLUMN SHAPE
ON PIER RESPONSE TO BARGE IMPACT LOADING

By

BIBO ZHANG

A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF ENGINEERING

UNIVERSITY OF FLORIDA

2004
ACKNOWLEDGEMENTS
I would like to thank my research advisor, Dr. Gary Consolazio for providing
continuous guidance, excellent research ideas, detailed teaching and all this with a lot of
patience. I am thankful for being able to learn so much during the past year and a half.
I would also like to extend my gratitude to Florida Department of Transportation
for providing funding for this project.
I would like to express my heartfelt thanks to all the graduate students who
worked on this project, especially Ben Lehr, David Cowan, Alex Biggs and Jessica
Hendrix. Their research helped me enormously in completing my thesis.
My family and friends have been very supportive throughout this effort. I wish to
thank them for their understanding and support.
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TABLE OF CONTENTS

page

ACKNOWLEDGEMENTS................................................................................................ii
LIST OF TABLES...............................................................................................................v
LIST OF FIGURES...........................................................................................................vi
ABSTRACT.......................................................................................................................ix
CHAPTER

1 INTRODUCTION........................................................................................................1
1.1 Overview.................................................................................................................1
1.2 Background of AASHTO Guide Specification......................................................2
1.3 Objective.................................................................................................................4

2 AASHTO BARGE AND BRIDGE COLLISION SPECIFICATION.........................5
3 FINITE ELEMENT BARGE IMPACT SIMULATION.............................................9
3.1 Introduction.............................................................................................................9
3.2 Background Study................................................................................................10
3.3 Pier Model Description.........................................................................................14
3.4 Barge Finite Element Model.................................................................................19
3.5 Contact Surface Modeling....................................................................................26

4 NON-LINEAR PIER BEHAVIOR DURING BARGE IMPACT.............................31
4.1 Case Study............................................................................................................31
4.2 Analysis Results....................................................................................................32

5 SIMULATION OF OBLIQUE IMPACT CONDITIONS.........................................37
5.1 Effect of Strike Angle on Barge Static Load-Deformation Relationship.............38
5.2 Effect of Strike Angle on Dynamic Loads and Pier Response.............................40
5.3 Dynamic Simulation Results................................................................................42

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6 EFFECT OF CONTACT SURFACE GEOMETRY ON PIER BEHAVIOR
DURING IMPACT.....................................................................................................52
6.1 Case Study............................................................................................................52
6.2 Results...................................................................................................................52

7 COMPARISON OF AASHTO PROVISIONS AND SIMULATION RESULTS....63
8 CONCLUSIONS........................................................................................................67
LIST OF REFERENCES...................................................................................................69
BIOGRAPHICAL SKETCH.............................................................................................71

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LIST OF TABLES
Table page

3-1 Comparison of original and adjusted section properties..........................................16
3-2 Input data in LS-DYNA simulations........................................................................18
3-3 Comparison of plastic moment and displacement using properties of pier cap.......19
3-4 Comparison of plastic moment and displacement using properties of pier
column......................................................................................................................19
3-5 General modeling features of the testing barge........................................................25
4-1 Dynamic simulation cases........................................................................................32
5-1 Dynamic simulation cases........................................................................................41
7-1 Peak forces computed using finite element impact simulation................................66

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LIST OF FIGURES
Figure page

1-1 Relation between impact force and barge damage depth according to Meir-
Dornberg’s Research (after AASHTO [1])................................................................3
2-1 Collision energy to be absorbed in relation with collision angle and the
coefficient of friction (after AASHTO [1])................................................................8
3-1 Global modeling of San-Diego Coronado Bay Bridge (after Dameron [10])..........11
3-2 Pier model used for local modeling (after Dameron [10]).......................................12
3-3 Global pier modeling for seismic retrofit analysis (after Dameron [10]).................12
3-4 Mechanical model for discrete element (after Hoit [11]).........................................13
3-5 Bilinear expression of moment-curvature and stress-strain curve...........................17
3-6 Moment-curvature derivation...................................................................................18
3-7 Main deck plan of the construction barge................................................................20
3-8 Outboard profile of the construction barge..............................................................20
3-9 Typical longitudinal truss of the construction barge................................................20
3-10 Typical transverse frame (cross bracing section) of the construction barge............20
3-11 Dimension and detail of barge bow of the construction barge.................................21
3-12 Layout of barge divisions.........................................................................................22
3-13 Meshing of internal structure of zone-1...................................................................23
3-14 Buoyancy spring distribution along the barge..........................................................26
3-15 Pier and contact surface layout.................................................................................27
3-16 Rigid links between pier column and contact surface..............................................27
3-17 Exaggerated deformation of pier column and contact surface during impact..........28
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3-18 Comparison of impact force versus crush depth for rigid and concrete contact
models......................................................................................................................29
3-19 Overview of barge and pier model for dynamic simulation.....................................30
4-1 Comparison of impact force history for severe impact case....................................34
4-2 Comparison of impact force history for non-severe case.........................................34
4-3 Impact force and crush depth relationship comparison for severe impact case.......35
4-4 Comparison of impact force – crush depth relationship for non-severe case..........35
4-5 Comparison of pier displacement for severe impact case........................................36
4-6 Comparison of pier displacement for non-severe case.............................................36
5-1 Static crush between pier and open hopper barge....................................................38
5-2 Results for static crush analysis conducting with a 4 ft. wide pier..........................39
5-3 Results for static crush analysis conducting with a 6 ft. wide pier..........................39
5-4 Results for static crush analysis conducting with a 8 ft. wide pier..........................40
5-5 Layout of barge head-on impact and oblique impact with pier................................41
5-6 Impact force in X direction for high speed impact on rectangular pier...................44
5-7 Impact force in X direction for high speed impact on circular pier.........................44
5-8 Impact force in X direction for low speed impact on rectangular pier.....................45
5-9 Impact force in X direction for low speed impact on circular pier..........................45
5-10 Impact force in Y direction for high-speed oblique impact.....................................46
5-11 Impact force in Y direction for low speed oblique impact.......................................46
5-12 Force-deformation results for high speed impact on rectangular pier......................47
5-13 Force deformation results for high speed impact on circular pier............................47
5-14 Force-deformation results for low speed impact on rectangular pier.......................48
5-15 Force-deformation results for low speed impact on circular pier............................48
5-16 Pier displacement in X direction for high speed impact on rectangular pier...........49
5-17 Pier displacement in X direction for low speed impact on rectangular pier............49
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5-18 Pier displacement in X direction for high speed impact on circular pier.................50
5-19 Pier displacement in X direction for low speed impact on circular pier..................50
5-20 Pier displacement in Y direction for high-speed oblique impact.............................51
5-21 Pier displacement in Y direction for low speed oblique impact..............................51
6-1 Impact force in X direction for high speed head-on impact.....................................54
6-2 Impact force in X direction for high speed oblique impact......................................55
6-3 Impact force in X direction for low speed head-on impact......................................55
6-4 Impact force in X direction for low speed oblique impact.......................................56
6-5 Impact force in Y direction for high speed oblique impact......................................56
6-6 Impact force in Y direction for low speed oblique impact.......................................57
6-7 Pier displacement in X direction for high speed head-on impact............................57
6-8 Pier displacement in X direction for high speed oblique impact.............................58
6-9 Pier displacement in X direction for low speed head-on impact..............................58
6-10 Pier displacement in X direction for low speed oblique impact..............................59
6-11 Pier displacement in Y direction for high speed oblique impact.............................59
6-12 Pier displacement in Y direction for low speed oblique impact..............................60
6-13 Vector-resultant force-deformation results for high speed head-on impact.............60
6-14 Vector-resultant force-deformation results for high speed oblique impact..............61
6-15 Vector-resultant force-deformation results for low speed head-on impact..............61
6-16 Vector-resultant force-deformation results for low speed oblique impact...............62
7-1 AASHTO and finite element loads in X direction...................................................64
7-2 AASHTO and finite element loads in Y direction...................................................65

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Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Engineering
INFLUENCE OF PIER NONLINEARITY, IMPACT ANGLE, AND COLUMN SHAPE
ON PIER RESPONSE TO BARGE IMPACT LOADING

By

Bibo Zhang

December 2004

Chair: Gary R. Consolazio
Major Department: Civil and Coastal Engineering

Current bridge design specifications for barge impact loading utilize information
such as barge weight, size, and speed, channel geometry, and bridge pier layout to
prescribe equivalent static loads for use in designing substructure components such as
piers. However, parameters such as pier stiffness and pier column geometry are not taken
into consideration. Additionally, due to the limited experimental vessel impact data that
are available and due to the dynamic nature of incidents such as vessel collisions, the
range of applicability of current design specifications is unclear. In this thesis, high
resolution nonlinear dynamic finite element impact simulations are used to quantify
impact loads and pier displacements generated during barge collisions. By conducting
parametric studies involving pier nonlinearity, impact angle, and impact zone geometry
(pier-column cross-sectional geometry), and then subsequently comparing the results to
those computed using current design provisions, the accuracy and range of applicability
of the design provisions are evaluated. The comparison of AASHTO provisions and
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simulation results shows that for high energy impacts, peak predicted barge impact forces
are approximately 60% of the equivalent static AASHTO loads. For low energy impacts,
peak dynamic impact forces predicted by simulation can be more than twice the
magnitude of the equivalent static AASHTO loads. However, because the simulation-
predicted loads are transient in nature whereas the AASHTO loads are static, additional
research is needed in order to more accurately compare results from the two methods.

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