FIB 39: Seismic bridge design and retrofit - structural solutions

298 Pages·2007·19.436 MB·English

Seismic bridge design
and retrofit –
structural solutions

State-of-art report
prepared by Task Group 7.4,

Seismic design and assessment procedures for bridges

May 2007
Subject to priorities defined by the Technical Council and the Presidium, the results of fib’s work in
Commissions and Task Groups are published in a continuously numbered series of technical publications
called 'Bulletins'. The following categories are used:
category minimum approval procedure required prior to publication
Technical Report approved by a Task Group and the Chairpersons of the Commission
State-of-Art Report approved by a Commission
Manual, Guide (to good practice) approved by the Technical Council of fib
or Recommendation
Model Code approved by the General Assembly of fib
Any publication not having met the above requirements will be clearly identified as preliminary draft.
This Bulletin N° 39 was approved as an fib state-of-art report by Commission 7, Seismic design, in 2006.
This report was mainly drafted by the following members of Task Group 7.4, Seismic design and assessment
procedures for bridges:
G. M. Calvi1,6 (Convenor, Univ. degli Studi di Pavia and ROSE School, IUSS, Italy), K. Kawashima1,11
(Convenor, Tokyo Institute of Technology, Japan), I. Billings8 (Beca Carter Hollings, Auckland, New
Zealand), A. Elnashai10 (Univ. of Illinois, USA), C. Nuti9 (Univ. di Roma Tre, Italy), A. Pecker5
(Géodynamique et Structure, France), P. E. Pinto7,10 (Univ. di Roma La Sapienza, Italy), N. M. J.
Priestley2,3 (ROSE School, IUSS, Italy), M. Rodriguez4 (Univ. Nacional Autonoma do Mexico, Mexico)
1,2,…. chapter number for which this TG member was the responsible author
Further relevant contributions to individual chapters were provided by
L. Di Sarno10 (Univ. degli Studi del Sannio, Italy), P. Franchin7,10 (Univ. di Roma La Sapienza, Italy),
D. Pietra6 (Ph. D. student, ROSE School, Italy; also assisted in proof-reading and reviewing all chapters),
I. Vanzi 9 (Univ. G. D’Annunzio, Italy).
1,2,…. chapter numbers
The valuable support, through discussions and comments, of other Task Group and Commission members not
mentioned here is gratefully acknowledged by the authors. Full address details of Task Group members may be
found in the fib Directory or through the online services on fib's website, www.fib-international.org.

Production note
The authors regret that some photos and diagrams for publication in this Bulletin could not be made available in
accordance with the usual fib quality requirements for off-set printing. As a result, a number of figures were
unsuitable for colour printing, and some may be difficult to read. As a service to readers of this Bulletin who may
wish to refer to the original (low-resolution) colour images, a number of figures have therefore been made
available for electronic viewing in a colour PDF file, which can be downloaded, free of charge, from the fib
website at www.fib-international.org/publications/fib/39. This is indicated in the Bulletin, where applicable, by a
note accompanying the relevant figures. The fib secretariat regrets any inconvenience caused by this procedure.
Cover photo: The Rion-Antirion Bridge near Patras (Greece), one of the winners of the 2006 fib Awards for
Outstanding Structures, Civil Engineering Structures category
© fédération internationale du béton (fib), 2007
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First published in 2007 by the International Federation for Structural Concrete (fib)
Postal address: Case Postale 88, CH-1015 Lausanne, Switzerland
Street address: Federal Institute of Technology Lausanne - EPFL, Section Génie Civil
Tel [phone] • Fax [phone]
[email protected] • www.fib-international.org
ISSN 1562-3610
ISBN 978-2-88394-079-6
Printed by Sprint-Digital-Druck, Stuttgart
.
Preface
This Bulletin represents a further evidence of the continued power of fib, heir of the illustrious
associations CEB and FIP, of attracting experts from all over the world to participate in tasks
that are most frequently challenging from both the intellectual as well as the material point of
view, with no other reward than the pleasure of learning from each other, of comparing
experiences, and producing worthy documents.
Consider the topic: bridges and earthquakes, and imagine a group of experts from places as
diverse as Japan, New Zealand, Europe, North and South America, having their first meeting
to discuss content and character of the future document. The initiative is voluntary, and the
higher decision bodies of fib rely on the seismic commission and its groups for the most
appropriate choice of the content. Opinions on best balance differ, being almost as many as
are the prevailing orientations of the members: design, analysis, assessment, isolation,
strengthening, experiment, reliability-based approaches, foundations, etc.
Agreeing on the titles in the list of content has been then a first successful effort, only to be
followed, however, by a continuous, patient, work, lasted for more than three years, of placate
and less placate discussions on exactly what material and in what form should be included or
not under each title. As one can understand, the problem was one of abundance, not of
scarcity, given the wealth of knowledge available within the group, and a great merit goes to
the convenors for their steering and to the active members for their goodwill to contemperate
their opinions with those of the others.
What can be said about the outcome? It is my true belief that this Bulletin rates quite high in
terms of comprehensiveness, state-of-the-art global information, clarity and rigour of
presentation. It is a small “summa” of the present state of knowledge regarding bridges
subjected to seismic action: it is more specialised than a textbook, but it is equally profitably
readable by engineers seriously engaged in the non-trivial task of seismic bridge design.
Paolo Emilio Pinto
Chairman of fib Commission 7, Seismic design
fib Bulletin 39: Seismic bridge design and retrofit – structural solutions iii
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Contents
PART I – INTRODUCTORY REMARKS
1 Introduction 1
1.1 Bridges and dreams 1
1.2 Bridge structural solutions 2
1.3 Current design practice and trends 2
1.4 Current developments 3
1.5 Problems with existing bridges 3
1.6 Dreams and reality 3
PART II – CURRENT DESIGN PRACTICE AND TRENDS
2 Pier section for bridges in seismic regions 5
2.1 Introduction 5
2.2 Single-column or multi-column piers 5
2.3 Column section shape 5
2.4 Hollow section columns 7
2.5 A regional review of design choices 10
References 18
3 Pier/superstructure connection details 19
3.1 Introduction 19
3.2 Advantages and disadvantages of support details 19
3.3 A regional review of design choices 21
References 22
4 Superstructure 23
4.1 Introduction 23
4.2 Section shapes for superstructures 23
4.3 Movements joints 25
4.3.1 Design practice in California – 4.3.2 Design practice in Japan –
4.3.3 Design practice in Greece
4.4 Stresses in bridge superstructures subjected to seismic actions 28
4.5 A regional review of design choices of bridge superstructure 29
References 40
5 Design of foundations 41
5.1 Overview of bridge foundations design 41
5.2 Spread foundations 42
5.2.1 Force evaluation – 5.2.2 Stability verifications –5.2.3 Structural design
5.3 Pile foundations 46
5.3.1 Pile types for bridge foundations – 5.3.2 Modeling techniques – 5.3.3 Pile
integrity checks
5.4 Design of foundations in a liquefiable environment 54
5.4.1 Shallow foundations – 5.4.2 Pile foundation
References 61
fib Bulletin 39: Seismic bridge design and retrofit – structural solutions v
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PART III – CURRENT DEVELOPMENTS
6 Design for enhanced control of damage 65
6.1 Basic concepts for enhanced damage control 65
6.2 Seismic structural control strategies 65
6.3 Bearings, isolators and energy dissipation units 66
6.3.1 General features – 6.3.2 Elastomeric bearings – 6.3.3 Sliding devices –
6.3.4 Metallic and Friction Dampers – 6.3.5 Viscous and Viscoelastic
Dampers – 6.3.6 Self-Centering Dampers – 6.3.7 Electro and
Magnetorheological Dampers – 6.3.8 Electro-inductive devices
6.4 Active and semi-active control systems 109
6.4.1 Optimal force control – 6.4.2 Optimal displacement control
6.5 Design concepts and analysis of deck – isolated bridges 110
6.5.1 Analysis concepts – 6.5.2 Basics of capacity design –
6.5.3 Considerations on input characteristics
6.6 Foundation rocking and pier base isolation 115
6.6.1 Basics of foundation rocking 6.6.2 Soil – Structure Interaction
(SSI) 6.6.3 Pier base isolation
6.7 Controlled rocking of piers and built–in isolators 116
6.7.1 Controlled rocking of combined concrete members – 6.7.2 Response of
partially prestressed coupled members – 6.7.3 Design and analysis of segmented
piers – 6.7.4 Unbonded columns and isolator built – in columns
References 123
7 Design for spatial variation of ground motion 129
7.1 Introduction 129
7.2 Analytical modelling 130
7.2.1 Model of spatial variability – 7.2.2 Generation of samples
7.3 Review of relevant past studies 134
7.3.1 Monti, Nuti and Pinto 1996 – 7.3.2 Lupoi, Franchin, Pinto and Monti
2005 – 7.3.3 Sextos, Kappos and Pitilakis 2003 – 7.3.4 Shinozuka, Saxena and
Deodatis 2000 – 7.3.5 Monti and Pinto 1998 – 7.3.6 Nuti and Vanzi 2004, 2005
7.4 Concluding remarks 155
References 156
8 Design for active fault crossing 159
8.1 Introduction 159
8.2 Fault effects and ground displacements 162
8.3 Planning issues 163
8.4 Performance requirements and design philosophy 164
8.5 Design steps 165
8.6 Design concepts 166
8.6.1 Design of fault crossing bridges
8.7 Retrofit design 167
8.8 Project examples 167
8.8.1 Bolu viaduct retrofit, Turkey – 8.8.2 Thorndon overbridge retrofit, New
Zealand – 8.8.3 Taiwan high speed rail project - Tuntzuchiao fault crossing –
8.8.4 Fujimi Dori Torii route bridge, Japan – 8.8.5 Rion Antirion bridge,
Greece – 8.8.6 I10/I215 interchange ramp, California
References 172
vi fib Bulletin 39: Seismic bridge design and retrofit – structural solutions
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PART IV – PROBLEMS WITH EXISTING BRIDGES
9 Screening of bridges for assessment and retrofit 175
9.1 Introduction 175
9.2 Classification of the methods 176
9.3 Review of the methods 177
9.3.1 Methods based on physical models only, (i.B): Kawashima et al., 1990,
Nielson et al., 2003 – 9.3.2 Methods based on engineering judgement and cost
of failure, (i.A) (ii,A,B): ATC, 1983, FHWA, 1995, WSDOT, 1991, Basoz and
Kiremidjian, 1996 – 9.3.3 Methods based on physical models and cost of failure,
(i.B) (ii.A or B)
9.4 Classification of minimisation problems 192
9.5 Conclusions 193
References 194
10 Fragility assessment 197
10.1 Introduction 197
10.2 Structural deficiencies 197
10.2.1 Span failure – 10.2.2 Pier failure – 10.2.3 Joint failure –
10.2.4 Abutment failure – 10.2.5 Footing failure
10.3 Limit states 204
10.3.1 Requirements for comprehensive limit states for assessment –
10.3.2 Observational limit states – 10.3.3 Limit states of functionality –
10.3.4 Analytical limit states
10.4 Methods of assessment 211
10.4.1 Observational methods – 10.4.2 Analytical methods – 10.4.3 Example
applications
10.5 Fragility assessment 226
10.5.1 Approaches for fragility assessment – 10.5.2 Background to probabilistic
fragility assessment – 10.5.3 Example applications
References 241
11 Seismic retrofit 247
11.1 Introduction 247
11.2 Retrofit of columns and piers 247
11.2.1 Introduction – 11.2.2 Steel jacketing – 11.2.3 Reinforced concrete jacket
and shear wall – 11.2.4 Composite material jackets – 11.2.5 Precast concrete
segment jacket
11.3 Retrofit of beam-column joints 271
11.3.1 Retrofit of cap beams – 11.3.2 Retrofit of cap beam/column joint regions
11.4 Retrofit of foundations 277
11.4.1 Introduction – 11.4.2 Retrofit of foundations to instability of
surroundings soils – 11.4.3 Shear and flexure retrofit of footings – 11.4.4 Cost-
effective dry-up construction method – 11.4.5 Micro piles – 11.4.6 Retrofit of
abutments
11.5 Retrofit of superstructures 286
11.6 Retrofit using dampers and isolation 287
11.6.1 Introduction – 11.6.2 Retrofit using seismic isolation – 11.6.3 Retrofit
using brace dampers
11.7 Other measures for seismic retrofit 292
References 294
fib Bulletin 39: Seismic bridge design and retrofit – structural solutions vii
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1 Introductory remarks
1.1 Bridges and dreams
“Imagine a world without bridges.”
This is the incipit of Petroski’s book ‘Engineers of dreams’1 where he describes how
“bridges have become symbols and souls of cities, and each city’s bridges have been shaped by,
and in turn shape, the character of that city”.
There is no question about the role that bridges have played in the development of
civilization, and no question about their power of evocation on people, as symbols of scientific
and technical advancement, of richness, and of power.
Bridge structures have also always occupied and still occupy a special place in the affection
of structural engineers, probably because in bridges the structural conception is more strictly
related to aesthetics and functionality than in most other construction types. For the same
reason bridges give the impression of being rather simple structural systems, whose seismic
response could be easily predicted. On the contrary, in recent earthquakes bridges did not
perform well, showing an increased need of research and understanding of different potential
problems and collapse mechanisms.
In recent years progress in design and assessment procedures have been achieved all over
the world and practices have changed.
Beautiful bridges have been built in high seismicity areas, such as the splendid Rion –
Antirion bridge, that recently won several awards for its excellence in design and construction.
Large viaducts were severely challenged by intense seismic action, such as in the case of the
Bolu Viaduct, that sustained significant damage during the November 1999, Duzce Earthquake
and had to be subjected to a complex and innovative repair and retrofit process.
Fig. 1.1: The Rion – Antirion bridge.
(Figure available electronically on fib website; see production note on p. ii)

1 Petroski, H., Engineers of dreams, Knopf, 1995
fib Bulletin 39: Seismic bridge design and retrofit – structural solutions 1
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Fig. 1.2: The Bolu Viaduct, design and operation for repositioning the superstructure
(Figure available electronically on fib website; see production note on p. ii)
1.2 Bridge structural solutions
In this context, it was felt useful and appropriate to present, discuss and critically compare
structural solutions for bridge seismic design and retrofit developed and used all over the world,
ten years after the publication of the last comprehensive manual on the subject2.
For this purpose, a truly international team of experts came together and cooperated actively
and intensely for more than three years, holding six meetings, in Greece, USA, Canada, France,
Italy, and Japan.
It was decided that the Bulletin should address problems with current design (comparing
current design practice and trends), current developments in specific areas (such as enhanced
damage control, spatial variability of ground motion and fault crossing) and problems to be
encountered when dealing with existing bridges (screening, assessment and strengthening).
These choices are reflected into the organization of the contents of the Bulletin, which is
briefly overviewed in the next sections.
1.3 Current design practice and trends
Consistent with the above discussion, the first four chapters of the Bulletin essentially
present a regional review of design choices, comparing and discussing design practice all over
the world, and pointing out relative merits and potential problems.
In chapter 2 pier sections are considered, discussing essential practices which are required
to design columns with sufficient strength and ductility capacity. Single vs. multi – columns,
solid vs. hollow shapes, a review of regional design choices and pier reinforcement details is
presented.
In chapter 3 superstructure – pier connections are described with an emphasis on advantage
and disadvantage of monolithic moment-resisting vs. bearing supported connection. A review
of regional design choices of connection and type of bearing describes presented.
In chapter 4 superstructure are addressed. Section shape, stiffness and weight of
superstructures, movement joints and seat length, precast vs. cast-in-place superstructures,
seismic analysis consideration and a review of regional design choices of superstructures is
introduced.
In chapter 5 design of foundations is tackled, discussing design of spread vs. pile
foundations and design of foundations in a liquefiable environment. A description of the typical
regional practice of type and design of foundations is also presented.

2 Priestley, M. J. N.,F. Seible and G. M. Calvi, Seismic design and retrofit of bridges, Wiley, 1996
2 1 Introductory remarks
.
1.4 Current developments
Current developments are treated in the next three chapters, with particular emphasis on
design for enhanced damage control, for spatial variation of ground motion and for fault
crossing.
In chapter 6 control strategies are discussed and presented in relation to possible choices of
bearing, isolation and dissipation units, foundation rocking, base isolation, controlled rocking
of piers and built in isolators.
In chapter 7 different models to represent the spatial variability of ground motion are
introduced, with reference to loss of coherence, wave passage and soil profiles.
In chapter 8 fault effects and ground displacements, planning issues, design philosophy and
concepts, retrofit choices and relevant case studies are presented, in relation to the general
subject of fault crossing.
1.5 Problems with existing bridges
The last part of the Bulletin presents a summary of current issues related to existing bridges.
In chapter 9 screening approaches for assessment and retrofit are introduced, presenting
methods based on physical models and on engineering judgement.
In chapter 10 methods for assessment of existing bridges are overviewed, with reference to
structural deficiencies, limit states, observation vs. analytical methods of assessment, and
fragility analysis approaches.
Finally, in chapter 11 aspects of retrofit design and examples are introduced, with specific
reference to columns and piers, beam column joints, foundations, superstructure, and
application of dampers and isolation to seismic retrofit.
1.6 Dreams and reality
As discussed in 11 chapters, extensive technical developments have been taking place in the
last two decades to make a reality of the dream that bridges serve as a most important
transportation infrastructure with limited damage during earthquakes. It is obvious from the
contents of this Bulletin that the effort towards this objective has been tremendous. Because
shapes and contents of the dreams depend on regional seismicity, system of transportation,
seismic performance goals, culture and peoples, design and construction practices with a wide
range spectrum are presented and discussed in this Bulletin.
The history of seismic design has been too often a repetition of damage produced by
earthquakes and consequent modification of design practices. We need to develop insight and
technology to solve hidden problems behind visible damage to make the dreams come true.
fib Bulletin 39: Seismic bridge design and retrofit – structural solutions 3