behavior and design of open steel box girder bridges by up-down construction method

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공학박사학위 논문



지점의 상승하강 공법을 이용한 개구제형 강합성
거더교의 설계와 거동


Behavior and Design of Open Steel Box Girder Bridges
by Up-down Construction Method

2009 년 8 월







인하대학교 대학원

토목공학과


도다이탕
(Do Dai Thang)
공학박사학위 논문



지점의 상승하강 공법을 이용한 개구제형 강합성
거더교의 설계와 거동


Behavior and Design of Open Steel Box Girder Bridges
by Up-down Construction Method

2009 년 8 월




지도교수 : 구 민세

이 논문을 박사학위 논문으로 제출함




인하대학교 대학원

토목공학과

도다이탕
(Do Dai Thang)
FF@FsPet'-"
BsR600Z
G&lb
Eo++
b&{vinbA &["te= €*t
[o
Behavior and Design of Open Steel Box Girder Bridges
by Up-down Construction Method

By

Do Dai Thang





A DISSERTATION


Submitted to the faculty of

INHA UNIVERSITY

In partial fulfillment of the requirements for the degree
of
DOCTOR OF PHILOSOPY


Department of Civil Engineering
August, 2009


- i -

ABSTRACT

This research investigates the behavior of open steel box girder bridge by
up-down construction method. The steel box girder with open-trapezoidal
cross section, partial-length prefabricated concrete slab and double
composite section by cast-in-place concrete on bottom flange is considered.
The three-dimensional finite element models, considering construction
sequence in modeling, have been used to carry out the analysis. A
parametric study is used to investigate the effects of some structural
characteristics on the behavior of steel box girder. These parameters include
the variation of lifting upward and lowering downward height, the length
and depth of bottom concrete slab, the length of partial prefabricated
concrete slab and the steel strength. A modification of the time-dependent
behavior for double composite section with difference in ages and modulus
of elasticity of top and bottom concrete slab are presented. An overview of
the effect of lifting upward and lowering downward to the stability design
such as web buckling and top lateral bracing are given. Optimization of the
plate thickness of cross section by considering construction sequences is
also presented as additional consideration. Finally the recommendations are
made for the engineers to the design and construct steel box girder bridges
by up-down construction method.

- ii -


TABLE OF CONTENTS
Title Page No.
Abstract i
Table of Contents ii
List of Figures v

List of Tables xi
CHAPTER 1 INTRODUCTION
1.1 Introduction 1
1.2 Objectives and Scope 2
1.3 Organization 4
CHAPTER 2 LITERATURE REVIEW
2.1 Fundamental of Up-Down Construction Method 6
2.2 Up-Down Construction Method Applied for Steel Box Girder 9
2.3 Double Composite 15
2.4 Partial Length Prefabricated Deck Concrete Slab 19
2.5 Proposed Up-Down Method for Open Steel Box Girder 20
2.6 Summary 26
CHAPTER 3 ANALYTICAL STUDIES
3.1 Finite Element Model Description 28
3.2 Nonlinear Finite Element Analysis Modeling 35

- iii -


3.4 Comparisons the Results 41
3.5 Summary 50
CHAPTER 4 PARAMETRIC STUDIES
4.1 Introduction 51
4.2 The Effect of Lifting-up and Lowering-down Height 52
4.3 The Effect of Bottom Concrete Slab 56
4.4 The Effect of Length of Partial Pre-fabricated Deck Concrete Slab 60
4.5 The Effect of Steel Strength 61
4.5 The Effect of the Top Flange 64
4.6 The Effect of Sequence Construction on Three, Four-Span Bridge 66
4.7 Summary 71

CHAPTER 5 TIME DEPENDENT ANALYSIS OF DOUBLE
COMPOSITE SECTION
5.1 Prediction Models of Creep and Shrinkage 73
5.2 Modified Gilbert’ Method, an Accurate Time-Dependent Analysis
with Consideration of Interval Time during Up-Down Method 76
5.3 Calculation of Short-term and Long-term Composite Section
according to AASHTO LRFD Specification 89
5.4 Comparisons of the Result 90
5.5 Summary 96


- iv -


CHAPTER 6 ADDITIONAL DESIGN CONSIDERATION
6.1 Stability Consideration 97
6.2 Suggested Construction Details 113
6.3 Optimum Cost of Steel Box-Girder by Varying Plate Thickness 117
6.4 Example Design and Evaluation 135
CHAPTER 7 SUMMARY AND CONCLUSIONS
7.1 Summary 141
7.2 Conclusions 143
7.3 Recommendations for Further Research 146
REFRENCES 148
APPENDIX A TIME DEPENDENT DESIGN OF COMPOSTIE
STEEL BOX GIRDER BRIDGE
A.1 Properties of Cross Section 155
A.2 Determination of Bending Moment during Construction Sequence 163
A.3 Time Dependent Analysis by Modification of Gilbert's Method 168
A.4 Time Dependent Analysis by AASHTO LRFD Provision 173

APPENDIX B DESIGN EXAMPLE

B.1 Calculation Bending Stress for Model 1 176
B.2 Calculation Bending Stress for Model 2 181
ACKNOWLEDGEMENTS 188

- v -


LIST OF FIGURES
Figure Page No.
2.1 Single span 7
2.2 Two continuous spans 8
2.3 Steel box girder in two continuous spans 12
2.4 Detail install bottom slab in steel box girder applied up-down
construction method 13
2.5 Double composite bridge Neuötting, (Hanswille, 2001) 17
2.6 Partial-length prefabricated steel box girder component 20
2.7 Construction sequence in two-spans continuous bridge 21
2.8 The normal stress at negative moment region 23
2.9 The normal stress at positive moment region 23
3.1 Example of Model 1 of two-span continuous bridge in
ANSYS 30
3.2 Model 1: a) Girder Side view b) Cross section 32
3.3 Model 2: a) Girder Side view b) Cross section 33
3.4 Idealized stress-strain relationships for steel (Bureau et. al.,
1998) 35
3.5 Uniaxial compressive and tensile stress-strain curve for
concrete a) Real curve relationships (Bangash 1989) b)
Idealized curve relationships (Hognestad, 1951) 36

- vi -


Figure Page No.
3.6 Residual stress distribution for 800mm flange 39
3.7 Residual stress distribution for 1,800mm height web 39
3.8 Idealized residual stress distribution in top and bottom flange
and web plates due to flame cutting and welding (AWS
2001) 41
3.9 Vertical deflection (at service stage) 42
3.10 Longitudinal stress of top flange at stage 3 (half bridge) 42
3.11 Longitudinal stress of top concrete slab at stage 5 (half
bridge) 42
3.12 Longitudinal stress of bottom concrete slab at stage 3 43
3.13 Equivalent stress at midpoint of top flange 45
3.14 Equivalent stress at midpoint of bottom flange 45
3.15 Longitudinal stress of top flange at midpoint 46
3.16 Longitudinal stress of bottom flange at midpoint 47
3.17 Longitudinal stress
of top concrete slab at midpoint 48
3.18 Longitudinal stress of top concrete slab at midpoint 48
3.19 Transverse stress of top slab across the width 49
3.20 Transverse stress of bottom slab across width at the support 49
3.21 Vertical deflection (at service state) 50

- vii -


Figure Page No.

4.1 Stress of top slab (in the case L=50m) 53
4.2 Initial compression stress of top slab 54
4.3 Upward lifting height for different span length 54
4.4 Relationship of the stress of top slab at service stage with lift-
up height in unequal two span bridge of 65-90m length 55
4.5 Compression stress of bottom slab in stage 4 57
4.6 Tensile stress of top flange in stage 3 58
4.7 Compression stress of bottom flange in stage 3 58
4.8 Bending moment diaphragm and location of cast-in-place the
top and bottom slab concrete 59
4.9 An example of slope for surface of bottom concrete slab 59
4.10 Parameter study result of prefabricated slab length 61
4.11 Layout of hybrid girder a) Grade 36/50 b) Grade 50/70 62
4.12 Variation of stress of top flange with respect the changing of
thickness or width of top flange at stage 3 (in case of L=50m) 65
4.13 Typical changing of thickness and width of top flange near
the support region. 65
4.14 Bending moment in case 1 of three-span continuous bridge 68
4.15 Bending moment in case 2 of three-span continuous bridge 68

- viii -


Figure Page No.
4.16 Bending moment in case 3 of three-span continuous bridge 68
4.17 Bending moment in case 1 of four-span continuous bridge 70
4.18 Bending moment in case 2 of four-span continuous bridge 70
4.19 Bending moment in case 3 of four-span continuous bridge 70
5.1 Prediction of creep coefficient using different models 75
5.2 Prediction of shrinkage strain using different models 76

5.3 Notification of cross section a) Elevation; b) Composite
section 0; c) Composite section 1; d) Composite section 2; d)
Short-term strain 77
5.4 Effect of different creep and shrinkage prediction models on
double composite section 92
6.1 Bending moment and shear force diaphragm due to lifting-up
the interior support 99
6.2 Finite element model M4 101
6.3 Tension field action in web at end panel of exterior supports 102
6.4 Tension field action in web at panel adjacent to interior
support 103
6.5 Tripping of top flange 103
6,6 Lateral torsional buckling 104
6.7 Cross section of a three-pan continuous bridge 106

- ix -


Figure Page No.
6.8 Steel box girder with longitudinal web stiffener 106
6.9 Arrangement of longitudinal stiffener in web plate 107
6.10 Transverse stiffener spacing in web plate at interior support 108
6.11 Top-lateral single-diagonal truss system 109
6.12 Torsional moment cause by shear force R
up
of one-tenth step .112
6.13 Top lateral bracing of Model 1 112
6.14 Ratio of top flange stress due to lift-up and girder self-weight 113
6.15 Construction details for Double composite section 114
6.16 Detail at support for the case of two load-bearing each side 115

6.17 Detail at support for the case of one load-bearing each side 115
6.18 Detail at support for case of one load-bearing each side 116
6.19 Stress in plate diaphragm at bearing 117
6.20 Structural geometry of steel box girder 121
6.21 A half of four-span continuous beam divided into 16
segments (case L=50m, seg=8) 123
6.22 Variations of equivalent weight for the case k
f
/k
m
=0 127
6.23 Variations of equivalent weight for different k
f
/k
m
127
6.24 Variations of
1
f
Δ
for different segment to L (w=200kN/m) 127

- x -


Figure Page No.
6.25 Variations of (a) equivalent weight; (b) height; (c) b/h ratio
with respect to L for different loading 129
6.26 Variations of (a) height h; (b) b/h with respect to L
(w=200kN/m) 130

6.27 Variation of thickness with respect to different segments
along the length (case: L=50m, w=200kN/m, seg=8) 131
6.28 Variation of thickness of web with respect to L or different
segment (w=200kN/m) 132
6.29 Variation of the ℓ/L ratio with respect to different segments
along the length (w=200kN/m, seg=8, all cases of L) 132
6.30 Bending moment diagram and resisting moment diagram 133
6.31 Result of longitudinal stress SZ in ANSYS (1) nodal
solution; (2) stress along middle top flange; (3) stress along
middle bottom flange 133
6.32 Design of two-span continuous bridge a) Conventional
design T1; b) Design T2; c) Proposed bridge design T3 136
6.33 Design of closed-rectangular brdige by up-down method R4
a) Side view; b) Positive moment area; c) Negative moment
area 137
6.34 Plate sizes design of steel box girder for Model 2 a)
Conventional bridge T1; b) Proposed bridge T3. 140
A.1 Notation of double composite cross section 155
A.2 a) Intermediate beam; b) Primary beam subject to external
loading, c) Primary loaded with redundant R
B
163

- xi -


LIST OF TABLES
Table Page No.
2.1 Comparison of characteristic in single span 7
2.2 Types of up-down construction methods 10

2.3 Comparison of cross section height and amount of material 14
2.4 Summarized the loading and composite section during the
up-down construction stage 27
3.1 Summarized cross section of Model 1 for parameter study 32
3.2 Material properties of steel 36
3.3 Material properties of concrete 37
3.4 Bending stress and total reaction comparisons 44
4.1 Unit cost of steel plate (Lwin, 2002) 62
4.2 Height of steel box girder in difference type of steel grade 63
4.3 Cost of steel material in difference type of steel grade 63
4.4 Cost ratio comparisons for the homogenous grade 50 63
4.5 Construction sequence on three-span continuous bridge 67
4.6 Construction sequence on four-span continuous bridge 69
5.1 Input variables for time-dependent creep and shrinkage
models 74

- xii -


Table Page No.
5.2 Section properties of composite sections 78
5.3 Construction sequence schedule and bending moment 91
5.4 Short term stress and long term stress in sagging moment at
stage 5 94
5.5 Short term stress and long term stress in hogging moment at
stage 5 95
5.6 Stress in hogging moment at service stage 95
5.7 Stress in sagging moment at service stage 96
6.1 List of ten first eigenvalues of buckling 101
6.2 Stress in the top lateral bracing strut system 112

6.3 Coefficient of moment for uniformly loaded continuous
beam over equal spans 122
6.4 Maximum values of height and thickness of web and flanges .125
6.5 Summary of variables and constraints 125
6.6 Results of optimization 133
6.7 Comparison of closed section, open section bridge designs 138
6.8 Comparison of open section bridge designs 138
6.9 Comparison of the bending stress 139
6.10 Comparison of designs of Model 2 140

- 1 -


CHAPTER 1
INTRODUCTION

1.1 Introduction
Steel box girders have a proven high structural efficiency because of their
large bending, torsional stiffness as well as rapid erection and therefore are
used in a wide variety of structural applications. However, they have
comparatively big section, noise and vibration. These demerits can be
reduced by using up-down construction method.
Up and down construction method is a new method for bridge construction
in which interior supports are lifted up and lowered down during the
construction stage to improve some of the structural characteristics of the
bridge system. It has been used for prestressed concrete bridges, preflex
bridges and steel box-girder bridges (MANSECOREA website, 2007). In
this construction method, the separate beams are connected at interior joints
with a continuity connection to get a continuous beam which reduces the
beam deflection. Double composite section is accomplished by pouring

concrete into the bottom flange at the negative moment region; it improves
the bending stiffness, prevents decay caused by rusting in the steel box
girder and reduces the effect of absorbed noise and vibrations. After lifting-
up the interior support, the top slab concrete was poured and cured, and then

- 2 -


the interior is lowered down; it causes initial compressive stresses in top
concrete slab over the interior piers, so the top slab is considered to endure
the negative bending moment.
However, the existing up-down method for steel box-girder is uneconomical
about material and construction time because of using closed rectangular
section and full in-situ casting of concrete in the deck. A steel box-girder
with open-trapezoidal cross section and partial-length prefabricated concrete
deck is proposed in this paper. In order to evaluate practicability of
proposed method, this study estimates analytically the elastic stresses of
steel and concrete during construction stages by considering full-scale
model of bridge with bracings, stiffeners and prefabricated concrete.
1.2 Objectives and Scope
The purpose of this research is to investigate the behavior of steel box girder
bridge during applied up-down construction method. This study investigates
the open-trapezoidal cross section of steel box girder, the partial-length
prefabricated deck concrete slab and double composite section at both
negative moment area by casting bottom concrete slab. A three-dimensional
full scale model are selected and developed in detail for the modeling of
steel box girder bridge structures. The effects of some structural
characteristics on the behavior of steel box girder are considered. This

- 3 -

research also considers the changing cross section of steel box girder due to
remarkable distribution bending moment. Finally, design method is also
proposed. The following tasks are targeted to achieve the above goals:
Task 1: Clarify the proposed up-down method applied for trapezoidal steel
box girder bridge with partial-length prefabricated deck concrete
slab. Evaluate the advantages of double composite by casting the
bottom concrete slab and of applying up-down construction method.
Task 2: Analyze the 3D models with focusing on the overall flexural elastic
behavior. Verify the accuracy of the FE model.
Task 3: Investigate the full nonlinear FEA solutions with some additional
important modeling considerations such as nonlinear material
properties of steel and concrete, residual stresses and geometric
imperfections.
Task 4: Take parametric FEA investigations to capture all the important
physical attributes that may have significant influence on the
strength behavior of these types of structures during construction
stage such as the lift-up and lower-down height, the thickness and
length of bottom slab, the length of partial-length fabricated top

- 4 -


slab, the steel strength and the construction sequence for bridge
with more than three spans continuous.
Task 5: Study the behavior of short-term and long-term of steel box girder
during construction sequence. Modify the time-dependent analysis
for double composite section.
Task 6: In additional design consideration, carry out the buckling analysis

and discuss the stability design of steel box girder during up-down
construction method. Present an optimization of the plate thickness
of cross section. Do examples to compare the results between the
conventional and proposed designs.
1.3 Organization
Chapter 2 provides the relevant theory dealing with fundamental of up-down
construction method. A brief fundamental of existing up-down construction
method applied to the bridge structure. Then, a review investigation of the
benefit of using double composite section and prefabricated deck concrete
slab are discussed. Finally, a proposal of steel box girder bridge applied up-
down construction method with double composite section is also outlined.
The three-dimension modeling and analysis of composite bridge systems are
discussed in Chapter 3. The full scale modeling with nonlinear behavior is
investigated and verified.

- 5 -


Chapter 4 contains six parametric studies to consider significant influence
on the strength behavior during construction stage.
Chapter 5 presents the time-dependent behavior for composite box girder
during construction sequence.
Chapter 6 presents some issues having related with the design of steel box
girder. They are discussion of stability design during up-down construction
and the optimization of section steel box girder due to remarkable
distribution of bending moment.
In Chapter 7, a summary of this research as well as key observations are
made. This chapter closes by identifying future research needs.
Appendix A presents detailed design of composite steel box girder. The
stresses in construction sequence, strength limit state and service state are

computed by AASHTO standard. Details of short-term and long-term
analysis are also provided in this appendix. Appendix B provides the
EXCEL spreadsheet for the detailed calculation of design example.


- 6 -


CHAPTER 2
LITERATURE REVIEW

2.1 Fundamental of Up-Down Construction Method
Up and down construction method applied for bridge superstructure is
invented and developed by Professor Koo Min-Se and his students since
1997. This is innovative method of bridge construction in which supports
are lifted up and lowered down during the construction stage to improve
some of the structural characteristics of the bridge system. It has been
researched, developed, and applied over 200 bridges for prestressed
concrete bridges, preflex bridges and steel box-girder bridges. In order to
understand the primary idea of up-down method, the comparison of single
and continuous span bridge between conventional system and developed
system is carried out as follows.
Single span
It is cleared that in the developed system the distribution bending moment
is more reasonable than conventional system; especially the deflection is
remarkably decrease in developed system as shown in table 2.1. Moreover,
there are two expansion joints in the conventional system, while there is
only one in the developed system because of one fixed end. So the
maintenance expansion joint at the abutment is easy.

- 7 -


Table 2.1 Comparison of characteristic in single span
Characteristic Conventional system Developed system
BC Hinged – Hinged Fixed - Hinged
Maximum
moment
2
wL
8
1

⎟
⎠
⎞
⎜
⎝
⎛
=
2
L
x at
2
wL
128
9

⎟
⎠

⎞
⎜
⎝
⎛
= L
8
3
x at
2
wL
8
1
− (at Lx = )
Maximum
deflection
EI
wL
384
5
4
=Δ
(at
L5.0x =
)
EI
wL
0054.0
4
=Δ
(at

L4215.0x
=
)


a) Conventional system b) Developed system
Fig. 2.1 Single span
Continuous span
There is similar comparison in the case the continuous span. In the
conventional system, the separate girders are made continuous through
cross beams and casting of deck concrete in the field. Restraint moments

- 8 -


develop in the superstructure due to the continuity and time-dependent
creep and shrinkage effects. In the negative moment over the intermediate
piers in continuous system, the crack occurs in concrete deck slab due to
weak tensile stresses of concrete, it make low durability and serviceability.

a) Conventional system

w
125

b) Developed system
Fig. 2.2 Two continuous spans
In developed continuous system the concrete girders are made continuous
through special connection joints. The constraint moments are considered
in the analysis and design. Greater continuity is obtained over a support

which reduces both the displacements and positive moments at the mid-
span of a girder. Compare with conventional system, the developed system
have some advantages such as generate smaller positive moment compared