Steel Concrete Composite Bridges

195 Pages·2005·25.339 MB·English

by  Collings, David

Steel–concrete composite
bridges
David Collings
PublishedbyThomasTelfordPublishing,ThomasTelfordLtd,
1HeronQuay,LondonE144JD.
www.thomastelford.com
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Firstpublished2005
Figures5.2,10.10,11.2courtesyofBenaim
Figure10.9courtesyofTHambly
Figures5.4,5.5courtesyofAmecGroupLtd
Figure10.12courtesyofArup.
AcataloguerecordforthisbookisavailablefromtheBritishLibrary
ISBN:0727733427
#ThomasTelfordLimited2005
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without the prior written permission of the Publishing Director, Thomas Telford Publishing,
ThomasTelfordLtd,1HeronQuay,LondonE144JD.
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ments made and opinions expressed in it and that its publication does not necessarily imply
that such statements and/or opinions are or reflect the views or opinions of the publishers.
Whileeveryefforthasbeenmadetoensurethatthestatementsmadeandtheopinionsexpressed
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inthisrespectbytheauthororpublishers.
TypesetbyAcademicþTechnical,Bristol
PrintedandboundinGreatBritainbyMPGBooks,Bodmin
Dedication
For my father
iii
Contents
Foreword ix
Acknowledgements x
Notation xi
1. General concepts 1
Introduction 1
Structural forms 1
Materials 2
Codes 2
Concrete 3
Steel 6
Composite action 11
Shear connectors 13
2. Simple beam bridges 16
Introduction 16
Initial sizing 16
Example 2.1 16
Initial design of girder 20
Bracing of the steelwork 20
Initial design of the concrete slab 25
Initial shear connector design 26
Safety through design 26
Environmental issues 27
3. Integral bridges 29
Introduction 29
Soil–structure interaction 30
Example 3.1 31
Weathering steel 34
Compact sections 38
Portal frame structures 38
Example 3.2 38
Effects of skew 40
Example 3.3 41
v
Painting 42
Shrinkage 44
Differential temperature 44
4. Continuous bridges 46
Introduction 46
Motorway widening 47
Moment–shear interaction 49
Example 4.1 50
Moment rounding 51
Cracking of concrete 53
Bearing stiffeners 55
Precamber 55
Natural frequency 57
Through-girder bridges 58
Example 4.2 60
Shear lag 61
Fatigue 63
5. Viaducts 66
Introduction 66
Concept design 66
Example 5.1 68
Articulation 69
Construction methods 71
Deck slab 74
6. Haunches and double composite action 78
Introduction 78
Haunches 78
Longitudinal shear at changes of section 79
Double composite action 80
Example 6.1 80
Slender webs 81
Lightweight concrete 83
7. Box girders 85
Introduction 85
Behaviour of boxes 85
Diaphragms 87
Example 7.1 88
Example 7.2 92
Noise from bridges 93
Shear connectors for composite boxes 94
Composite plates 95
Example 7.3 97
vi
8. Trusses 98
Introduction 98
Example 8.1 99
Member type 101
Steel sections under axial load 101
Joints in steelwork 102
Example 8.2 103
Enclosure 104
Local loading of webs 107
Continuous trusses 109
High-strength steel 110
9. Arches 111
Introduction 111
Example 9.1 112
Composite compression members 114
Example 9.2 117
Fabrication of curved sections 118
Nodes in tubular structures 118
Aesthetics 120
Tied arches 122
Example 9.3 123
Arch buckling 124
10. Cable-stayed bridges 129
Introduction 129
Deck–stay connection 130
Example 10.1 131
High-strength concrete 131
Buckling interaction 137
Shear connection 138
Towers 139
Tower top 140
Example 10.2 141
Stainless steel 142
Strain-limited composite section 143
11. Prestressed steel–concrete composite bridges 145
Introduction 145
Displacement of supports 145
Prestress using tendons 146
Design of prestressed composite structures 147
Prestress losses 148
Example 11.1 149
Durability 151
Prestressed composite box girders 151
Corrugated webs 151
Example 11.2 152
Extra-dosed bridges 153
vii
12. Assessment of composite bridges 155
Introduction 155
History 155
Structure types 157
Inspection 157
Loads 157
Materials 159
Testing of the shear connection 160
Analysis 160
Incidental and partial composite action 161
Cased beams 161
Strengthening 162
Life-cycle considerations 162
Appendix A: Approximate methods 164
Appendix B: Calculation of section properties 165
Section properties for steel sections 165
Section properties for steel–concrete composite sections 165
Section properties for cracked steel–concrete composite sections with
reinforcement 166
Appendix C: Section properties for examples 167
Appendix D: Plastic section properties for steel–concrete composite
sections 168
Appendix E: Torsional properties for steel–concrete composite
sections 170
Appendix F: Moment–axial load interaction for compact
steel–concrete composite sections 171
References 172
Index 177
viii
Foreword
The bridge crossing it, with its numberless short spans and lack of bigness, beauty and
romance he gazed upon in instant distain. It appeared to creep, cringing and apologetic,
across the wide waters which felt the humiliation of its presence...Yet he received a
shock of elation as the train had moved slowly along the bridge, carrying him with it, and
he gazed downward upon flowing waters, again he marvelled at what men could do; at the
power of men to build; to build a bridge so strong... [1].
I see this book as a journey. A journey of experience from the first simple river
crossing to the more complex suspended spans of the early twenty-first century.
A journey across the world from the bleak post-industrial landscapes that are still
scattered across Britain, around the broad untamed rivers of Bengal and into the
racing development of South East Asia. But it is also a subjective journey, over
and under the numberless spans of motorway bridges that are the ‘bread and
butter’ of many bridge designers, through to the countless bridges that perform
their task with pride, and always marvelling at how we build so strong, always
questioning.
ThisbookhasitsoriginsinthecompositebridgechapteroftheManualofBridge
Engineering[139].Thisbookexpandsuponthatchapterandprovidesdetailsofmore
steel–concrete composite bridges. It is intended to show how composite bridges
may be designed simply from basic concepts without the need for a clause-by-
clause checking of codes and standards. All chapters use examples of various
bridges to illustrate the design and construction methods. The book looks impar-
tially at this construction form and compares composite bridges with other types,
and often places limits on their use. The book is intended for a number of
readers, first those who use the Manual of Bridge Engineering and wish to find more
detail on steel–concrete composite bridges. Second, it is for those engaged in
design who require a deeper understanding of the methods used as well as how
they are verified against design codes. The book aims to show how to choose the
bridge form, and design element sizes to enable drawings to be produced. The
book covers a wide range of examples, in all of which the author has had an
involvement or interest.
ix
Acknowledgements
Many of the examples and photographs are derived from work carried out at
Benaim, and the support of the staff and directors is gratefully acknowledged.
Particular thanks go to Rup Shandu for his help with drafting some of the more
complex figures and to Robert Henderson for patiently reading the drafts of each
chapter.
I would like to thank John Bowes and Phil Girling for the aerial views of the
Doncaster Viaduct and Brian Bell for the photographs of the Irish bridges, not
all of which were used in the final version. I am also indebted to Naeem Hussain
and Steve Kite of Arup for the information on the Stonecutters Bridge tower,
and to Sally Sunderland for the information on Brunel’s Paddington Bridge.
x
Notation
A area
A steel area
a
A composite section
ac
A concrete area
c
A reinforcing steel area
s
B width
D depth of girder, rigidity
E Young’s modulus
E steel modulus of elasticity
a
E concrete modulus of elasticity
c
E long-term concrete modulus
c0
F force or load
F force on fixed bearings
F
G permanent load, shear modulus
H height
I second moment of area
J torsional constant
J mass moment of inertia
m
K stiffness of member, soil pressure coefficient
L length of beam or slab
L effective length
e
M moment
M design resistance moment
D
M design resistance moment of flanges
f
M ultimate moment
u
M0 reduction of moment
N axial load
N design resistance load
D
No number of connectors
N chord plastification-k joint
pk
N chord plastification-x joint
px
N ultimate axial resistance
u
N squash load
ul
P load on single connector, bolt capacity, wind susceptibility factor
P initial prestress
i
P prestress force after losses
o
P resistance of a connector
u
P resistance of a connector in lightweight concrete
UL
xi