Highway Bridge Superstructure Engineering : LRFD Approaches to Design and Analysis

959 Pages·2014·27.93 MB·English

by  Narendra Taly

Highway Bridge
Superstructure
Engineering
LRFD Approaches
to Design and Analysis

Highway Bridge
Superstructure
Engineering
LRFD Approaches
to Design and Analysis
Narendra Taly

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Library of Congress Cataloging‑in‑Publication Data
Taly, Narendra.
Highway bridge superstructure engineering : LRFD approaches to design and analysis / author,
Narendra Taly.
pages cm
Includes bibliographical references and index.
ISBN 978-1-4665-5218-0 (alk. paper)
1. Bridges--Design and construction. 2. Structural engineering. 3. Load factor design. I. Title.
TG260.T35 2014
624.2’57--dc23 2014011986
Visit the Taylor & Francis Web site at
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To
Trish Taly
For her high-limit states of stress endurance over the years, which made
the publication of this book and author’s previous books a reality.
And to the memory of my parents, Bhagwan Das and Sundar Bai Taly,
who taught me the importance and virtues of academics.

Contents
Preface.............................................................................................................................................xix
Acknowledgments.........................................................................................................................xxiii
Chapter 1 Introduction...................................................................................................................1
1.1. Structural.Design.Philosophies..........................................................................1
1.2. General.Design.Concepts...................................................................................1
1.3. Fundamentals.of.Structural.Design.Philosophies..............................................2
1.3.1. Design.Philosophies.Based.on.Elastic.Behavior:.Allowable/
Working.Stress.Design..........................................................................2
1.3.2. Design.Philosophies.Based.on.Inelastic.Behavior:.Plastic.
Design.Method......................................................................................3
1.4. Limit.States.Design.Philosophies.......................................................................8
1.4.1. Concepts.of.Limit.States.......................................................................8
1.4.1.1. Strength.Limit.States.............................................................9
1.4.1.2. Serviceability.Limit.States..................................................10
1.4.1.3. Fatigue.Limit.States.............................................................12
1.4.2. Strength.Limit.States.versus.Serviceability.Limit.States...................13
1.4.3. Strength.Design,.Load.Factor.Design,.and.Load.and.Resistance.
Factor.Design......................................................................................14
1.4.4. Strength.Design.Philosophy................................................................14
1.4.4.1. Strength.Design.Concept.....................................................14
1.4.4.2. Load.Factor.Design..............................................................15
1.4.4.3. Load.and.Resistance.Factor.Design.....................................15
1.5. LRFD.Specifications.for.Highway.Bridges......................................................16
1.5.1. Evolution.of.LRFD.Specifications.for.the.Design.of.Steel.
Buildings.in.the.United.States.............................................................16
1.5.2. Evolution.of.LRFD.Specifications.for.Highway.Bridges.in.the.
United.States.......................................................................................16
1.5.2.1. Why.the.Change.from.AASHTO.Standard.
Specifications?.....................................................................16
1.5.2.2. Why.Probability-Based.Design.Philosophy?.......................17
1.5.3. Issues.and.Considerations.for.the.Development.of.AASHTO.
LRFD.Criteria.....................................................................................18
1.5.4. Probabilistic.Basis.of.AASHTO.LRFD.Bridge.Design.
Specifications......................................................................................18
1.5.5. Statistical.Nature.of.Loads.and.Resistances.......................................19
1.5.5.1. Random.Variables,.Normal.and.Lognormal.
Distributions,.and.Probability..............................................19
1.5.5.2. Properties.and.Applications.of.Normal.(Gaussian).
Distribution..........................................................................26
1.5.5.3. Linear.Functions.of.Random.Variables:.Central.Limit.
Theorem.(CLT,.Normal.Convergence.Theorem).................37
1.5.6. Probabilistic.Determination.of.Safety.Factors....................................39
1.5.6.1. Probabilistic.Concept.of.Safety:.Limit.State.Function.
(Performance.Function).......................................................39
vii
viii Contents
1.5.6.2. Development.of.AISC.LRFD.Criteria.................................40
1.5.6.3. Development.of.AASHTO.LRFD.Criteria..........................44
1.5.6.4. Calibration.Procedure..........................................................52
1.5.6.5. Calibration.of.Load.and.Resistance.Factors........................55
1.5.7. AASHTO.LRFD.Specifications.Format.of.Load.and.Resistance.
Relationship.........................................................................................56
1.5.7.1. Loads,.Resistance,.and.Factor.of.Safety..............................56
1.6. Differences.between.Various.Design.Methods:.Summary..............................63
1.6.1. Difference.between.the.Design.Methods.Based.on.the.Elastic.
and.Inelastic.Material.Behavior..........................................................63
1.6.2. Difference.between.Plastic.Design,.Strength.Design,.
Load Factor Design,.and.Load.and.Resistance.Factor.Design............64
1.7. Historical.Review.of.AASHTO.Specifications.for.Highway.Bridges..............64
1.8. AASHTO.LRFD.Highway.Bridge.Design.Specifications.and.Design.
Philosophies......................................................................................................65
1.9. AASHTO.Interim.Specifications.....................................................................65
1.10. Scope.of.the.AASHTO.LRFD.Bridge.Design.Specifications..........................66
1.11. Commentary.to.AASHTO.LRFD.Specifications............................................67
1.12. General.Comments...........................................................................................67
1.A. Appendix...........................................................................................................68
References...................................................................................................................70
Chapter 2 Highway.Bridge.Superstructure.Systems....................................................................73
2.1. Introduction......................................................................................................73
2.2. AASHTO.LRFD.Spec.-Specific.Highway.Bridge.Superstructures.................73
2.3. Description.and.Design.Characteristics.of Superstructure.Systems.
in Table.2.1.......................................................................................................81
2.3.1. RC.Deck.over.Steel.Wide.Flange.Beams.of.Plate.Girders.(Type.a).....81
2.3.2. Spread-Box.Beam.Superstructure.(Type.b)........................................83
2.3.3. Open.Steel.or.Precast.Concrete.Box.Superstructure.(Type.c)............83
2.3.4. Cast-in-Place.Concrete.Multicell.Box.Girder.(Type.d)......................84
2.3.5. Cast-in-Place.RC.T-Beam.Superstructure.(Type.e)............................85
2.3.6. Adjacent-Prestressed.Concrete.Box.Superstructure.(Type.f ).............85
2.3.7. Adjacent-Prestressed.Concrete.Box.Superstructure.with.
Integral.Concrete.Deck.with.or.without.Transverse.
Posttensioning.(Type.g)......................................................................85
2.3.8. Precast.Concrete.Channel.Sections.with.Shear.Keys.
and Concrete.Overlay.(Type.h)...........................................................86
2.3.9. Precast.Concrete.Double-T.Girders.with.Shear.Keys,.and.with.
or.without.Transverse.Posttensioning.and.Integral.Concrete.
Deck.(Type.i).......................................................................................87
2.3.10. Precast.Concrete.Single-T.Girders.with.Shear.Keys,.and.with.or.
without.Transverse.Posttensioning.and.Integral.Concrete.Deck.
(Type.j)................................................................................................87
2.3.11. RC.Deck.over.Prestressed.I-Beams.or.Bulb-T.Girders.(Type.k)........87
2.3.12. Fiber-Reinforced.Polymer.Highway.Superstructure.Systems.............89
2.4. Diaphragms......................................................................................................91
2.4.1. Definition.of.a.Diaphragm..................................................................91
2.4.2. Diaphragms.in.Building.Structures....................................................91
Contents ix
2.4.3. Diaphragms.in.Bridge.Superstructures...............................................91
2.4.3.1. ASSHTO.Standard.Specifications.for.Diaphragms............92
2.4.3.2. AASHTO.LRFD.Specifications.for.Diaphragms.and.
Cross-Frames.......................................................................93
2.5. Bridge.Site.and.Geometry................................................................................94
2.5.1. Bridge.Type,.Size,.and.Location.........................................................94
2.5.2. Bridge.Width.......................................................................................95
2.5.3. Normal.and.Skewed.Bridges...............................................................95
2.6. Deflections........................................................................................................97
2.6.1. Historical.Review.of.Deflection.Limitations......................................97
2.6.2. Purpose.of.Limiting.Bridge.Deflections.............................................98
2.6.3. Criteria.for.Live.Load.Deflections......................................................99
2.6.4. Optional.Criteria.for.Span-to-Depth.Ratios......................................101
2.6.4.1. Optional.Deflection.Criteria.for.Constant.Depth.
Superstructures..................................................................101
2.6.4.2. Optional.Deflection.Criteria.for.Curved.Steel.
Superstructures..................................................................102
2.6.5. Deflections.Due.to.Dead.Loads........................................................102
2.6.6. Calculation.of.Live.Load.Deflections...............................................103
2.7. Consideration.of.Future.Widening.................................................................106
2.8. Constructability..............................................................................................106
2.9. Bridge.Esthetics..............................................................................................107
References.................................................................................................................107
Chapter 3 Loads.on.Highway.Bridge.Structures.......................................................................109
3.1. Introduction....................................................................................................109
3.2. AASHTO.LRFD.Highway.Bridge.Design.Philosophy..................................110
3.2.1. Limit.States.Concept.........................................................................110
3.2.2. Loads.and.Load.Designations...........................................................114
3.2.3. Load.Factors.and.Load.Combinations.for.Design.Loads..................114
3.2.4. Selection.of.Design-Specific.Limit.States,.Load.Modifiers,.
Load.Combinations,.and.Load.Factors.............................................120
3.3. Load.Factors.and.Load.Combinations.for.Construction.Loads.....................120
3.3.1. Evaluation.at.the.Strength.Limit.States.............................................120
3.3.2. Evaluation.of.Deflection.at.the.Service.Limit.State..........................120
3.3.3. Load.Factors.for.Jacking.and.Posttensioning.Forces........................121
3.3.3.1. Jacking.Forces...................................................................121
3.3.3.2. Force.for.Posttensioning.Anchorage.Zones.......................121
3.4. Components.of.a.Highway.Bridge.Structure..................................................121
3.5. Dead.Loads.on.a.Highway.Bridge.Superstructure.........................................122
3.5.1. General..............................................................................................122
3.5.2. Dead.Load.Due.to.Deck.Slab............................................................124
3.5.3. Dead.Load.Due.to.Girders................................................................124
3.6. Construction.Loads........................................................................................130
3.7. Live.Loads.on.Highway.Bridge.Superstructures............................................130
3.7.1. Historical.Perspective........................................................................130
3.7.2. Development.of.AASHTO.Standard.Specifications.Live.Load.
Model.................................................................................................131
x Contents
3.7.3. Description.of.AASHTO.LRFD.Notional.Live.Load.Model...........135
3.7.4. Understanding.the.Development.of.AASHTO.LRFD.Notional.
Live.Load.Model...............................................................................139
3.7.4.1. Concept.of.Notional.Load:.What.Is.It?..............................139
3.7.4.2. Commercial.Vehicular.Loads............................................140
3.7.4.3. Development.of.AASHTO.LRFD.Notional.Live.
Load:.A.Brief.History........................................................146
3.7.4.4. Permit.Loads......................................................................156
3.7.5. Application.of.Design.Vehicular.Live.Loads.on.Bridge.
Superstructures..................................................................................158
3.7.5.1. Position.of.Live.Load.on.Simple.Spans.............................158
3.7.5.2. Position.of.Vehicular.Live.Loads.on.
Continuous Spans.........................................................160
3.7.6. Bending.Moments.and.Shears.Due.to.Moving.Loads.on.Simple.
Spans.................................................................................................160
3.7.6.1. Bending.Moments..............................................................160
3.7.6.2. Influence.Lines.for.Absolute.Maximum.Bending.
Moments.in.Simple.Spans.................................................161
3.7.7. Generalized.Expressions.for.Maximum.Moment.and.Maximum.
Shear.at.a.Section.in.a.Simple.Span.Due.to.HS20.Truck..................175
3.7.7.1. Maximum.Moment.and.Shear:.HS20.Truck.Moving.
from.Left.to.Right..............................................................175
3.7.7.2. Maximum.Moment.and.Shear:.HS20.Truck.Moving.
from.Right.to.Left..............................................................176
3.7.8. Absolute.Maximum.Bending.Moment.in.Spans.Due.to Loads.
Other.than.AASHTO.HS20.Truck....................................................178
3.7.9. Governing.Span.Lengths.for.Maximum.Live.Load.Shear.in.
Simple.Spans.Due.to.AASHTO.LRFD.Live.Load:.HS20.Truck.
and.Tandem.......................................................................................183
3.7.10. Influence.Lines.for.Beams.with.Other.Support.Conditions.
and for.Other.Types.of.Structures.....................................................184
3.8. Dynamic.Effects.of.Vehicular.Live.Load......................................................185
3.8.1. General.Considerations.for.Dynamic.Force.Effects:.Dynamic.
Load.Allowance................................................................................185
3.8.2. Research.on.Quantification.of.Dynamic.Load.Effects.....................185
3.8.3. AASHTO.LRFD.Specifications.for.Dynamic.Load.Allowance.......193
3.8.4. Exceptions.to.Application.of.Dynamic.Load.Effects.......................197
3.9. Fatigue.Loading..............................................................................................198
3.9.1. Fatigue.Phenomenon.........................................................................198
3.9.2. Magnitude.and.Configuration.of.Live.Load.for.Fatigue.
Considerations...................................................................................198
3.9.3. Formulas.for.Maximum.Moment.and.Shear.for.Fatigue.Limit.
State.Loading....................................................................................199
3.9.3.1. Maximum.Moment.for.Fatigue.Limit.State......................199
3.9.3.2. Maximum.Shear.for.Fatigue.Limit.State...........................202
3.9.4. Frequency.of.Loading.for.Fatigue.Design.Considerations................206
3.9.5. Application.of.ADTT .for.Determination.of.Fatigue.
SL
Limit State....................................................................................209
3.10. Pedestrian.Loads............................................................................................210
3.10.1. Significance.of.Pedestrian.Loading..................................................210
3.10.2. Live.Load.Due.to.Sidewalks.on.Vehicular.Bridges..........................210