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7/31/2019 Lee Presentation

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Sustainable Development in Bridge

En ineerin : Develo ment of MultiHazard Design Guidelines


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QuotationQuotation

Sustainability is a condition of existence

humans and other species to enjoy social well

being, a vibrant economy, and a healthyenvironment, and to experience fulfillment,

beauty and joy, without compromising the

a y o u ure genera ons o umans another species to enjoy the same.

,


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QuotationQuotation

Achieving sustainable development is perhaps

pressing goals we face. It requires on the part

of all of us commitment, action, partnershipsand, sometimes, sacrifices of our traditional life

pattern and personal interests.

Abraham Lincoln, 1864


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Sustainable Development in Bridge

ng neer ng: eve opmen o u -Hazard Desi n Guidelines

o e o s ruc ura eng neer ng

in sustainable development is

illustrated by an exampleexample of bridgeengineering research project.


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OutlineOutline.

2. Structural Desi n of Brid es in US

3. Development of Multi-Hazard LRFD

Progress Report

.


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IntroductionIntroduction

Sustainability An Emerging

A emerging field in science and engineering To achieve reasonable balance among

economic, environmental and societal

A significant component of sustainable


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Introduction (contd)

Sustainabilit and Structural En ineerin

Structural Engineering Emphases

Safety

Serviceability os Other

Environment/ecosystems quality Natural resources conservation Integrated consideration of present and future

Other


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Introduction (contd)

Sustainabilit and Structural En ineerin

Energy Consumption in USBuildings 40%

Industry 32%

Construction Waste:

ore an s concre e. Issues in Design Codes

Many over-conservative features

Some unsafe features


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Introduction (contd)Sustainability and Structural Engineering (contd)

ssues nvo v ng ruc ura es gnssues nvo v ng ruc ura es gn

Demand Ca acit

Demand involves all types of long term and short.

Capacity involves materials, analysis methods,failure modes, life cycle cost and sustainability

issues (e.g. reuse, retrofit and reuse, recycle,construction methods, energy, environmental

, .

Sustainable design requires holistic consideration.


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Introduction (contd)Sustainability and Structural Engineering (contd)

ssues nvo v ng ruc ura es gnssues nvo v ng ruc ura es gn

Demand Ca acit

How to set reasonable level of demand,

How to design a structure that fails at a load

Is no collapse a reasonable seismic

perspective?


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Structural Design of Bridges in US

Load and Resistance Factors Design (LRFD)approach calibrated for non-extreme loads

Individual desi n uidelines for variousextreme hazard loads under development

-hazard LRFD to achieve fully reliability-baseddesi n uidelines


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Structural Design of Bridges in US (contd)

Current LRFD specifications for basic bridges ruc ura componen s on wasinitially adopted by American Association of

(AASHTO) in 1994.

Fully calibrated for dead load and live load

only

Since then development of LRFD for otheraspec s o r ge sys ems ave een

initiated.


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LRFD (contd)

Significance of AASHTO LRFDSignificance of AASHTO LRFD

ASD (LFD) and LRFD have virtually

based on load intensities.

i iwhere R = resistance = resistance factor

Qi = loads i = load factors


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LRFD (contd)

Significance of AASHTO LRFD (contd)Significance of AASHTO LRFD (contd)

LRFD provides additional information on

decision making.

failure i iwhere

failure


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LRFD (contd)

Probability Distribution o Load and ResistanceProbability Distribution o Load and Resistance


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Limit state function Z = R Q

Failure occurs when Q > R

If Z is normal distribution,[ ]FP P Q R

Z

[ 0]P Z Z

Z

Probability of failure


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Load and Resistance Factors Desi n LRFD contd

Design limit state = Z = R Q = 0

Probability distribution

of Resistance and loadwith respect to the

limit state


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Reliability Index and Corresponding ProbabilityReliability Index and Corresponding Probability


LRFD (contd)

Prob. ofProb. ofexceedanceexceedance

RoundedRoundedreciprocalreciprocal

(approx. 1(approx. 1--inin--n)n)

. .

0.5 0.3085375 3

1 0.1586553 6. .

2 0.0227501 50

2.5 0.0062097 200

. ,

3.5 0.0002326 5,000

4 3.167E-05 30,000

. . - ,

5 2.867E-07 3,500,000

5.5 1.899E-08 50,000,000


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Load and Resistance Factors Design (LRFD) (contd)

Reference:Kulicki, J. M. (2005). Past, Present and

Future of Load and Resistance Factor

Design, Journal of the TRB.


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Current Practice of Bridge Design AgainstExtreme Hazard Loads

Various current research efforts are devoted tobridge component performance and design forindividual extreme hazard load effects (e.g.earth uake tidal waves vessel collision etc.

Very limited efforts to consider the combinations ofextreme hazard load effects, either on thecomponen s or e r ge as a sys em o

components.


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Current Practice of Bridge Design (contd)

Status in AASHTO LRFD

Dead Load Calibrated

Live Load Calibrated

Earthquake Included (Guidespec), but not completely calibrated

Scour Not in LRFD framework

EarthquakeScour

WindIntegrated in AASHTO LRFD strength limit state,

not completely calibrated

FireNew giudance information available from NCHRP

study

Storm SurgeWind

Vessel Collision Structurally consistent with LRFD, but not calibratedconsistently

Vehicular

CollisionRough estimate based on limited dataVessel collision Vehicular collision

Storm Surge New Guidespec provide design procedures

Debris Flow Provisions on debris raft (part of WA)

FireJohn Huseby, CaltransLandslide/debris flow


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,

All- Hazard LRFD

Many bridge failures due to various extreme hazardevents in recent years

-

MCEER in 2008, funded by FHWA

To establish uidin rinci les for the develo ment

of multi-hazard LRFD with emphasis given todesign limit states for collapse failures due to

-

(Demand emphasis)


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Development of Multi-Hazard LRFD (contd)

gn can a enge o eve op nggn can a enge o eve op ng

MHMH--LRFDLRFD

Demand

CapacityTo establish

reliable, sim le, all-

To design structures

with redictable

hazard design limitstatus considering

behavior for highlyunpredictable hazard

non-extreme and

extreme loads.

load effects.


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MCEER Research Project

Develop design principles and framework for

MH-LRFD desi n limit states

Establish selected design limit statee uations as exam les

Work closely with AASHTO T5, FHWA andex erienced desi n rofessionals


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Some Project Challenges

Extreme hazard events are mostl randomprocesses.

Methodology to relate and combine theprobability distribution functions of bridge

failures due to two or more extreme load

e ec s Very limited data on bridge failures due to

ex reme even s or purpose o ca ra on

Outcome must be simple to use.


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Some Pro ect Challen es contd


Two (or more) extreme load

pfailure = P ( R iQi)

Exam leExam le: Consider

D (dead load), T (truck load) and E (earthquake load)

f D, T, E


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Some Project Challenges (contd)

DL: Normal distribution.

Nominal super-structural mass is 600 ton.(not used in this example)

: r angu ar s r u on.

Max truck mass = 30 ton.Min truck mass = 1.0 ton.

Max number of trucks passing through thebridge in 10 seconds is 8.

EL: Vertical component = lognamal

distribution in 75 year period.


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Some Project Challenges (contd)

Example of TL and EL Combinations

Definitions:

=

EDT = Event time interval (seconds)

= v TSY = Total service life of bridge in years

Earth Direct = Max. possible EL in TSY


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Example of TL and EL Combinations (contd)

4

6x 10

- Probability Mass Curve of Dead Load

ss

0

2PM

. .

x 104Intensity (KN)

1Cumulative Probability Mass Curve of Dead Load

0.5

CPMass

0 0.5 1 1.5 2

x 104

0

Intensity (KN)


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-3



6

8

ass

0 50 100 150 200 250 3000

2P

Intensity (KN)

1Cumulative Probability Mass Curve of Each Passing Truck

0.5

CPMa

s

0 50 100 150 200 250 3000

Intensity (KN)


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-3 Truck Load Prob. Mass Curve for Varied Num. of Truck



7

8

1 Truck Passing2 Truck Passing

3 Truck Passing

5

6

Mass

4 ruc ass ng

5 Truck Passing

6 Truck Passing

7 Truck Passing

3

4

Probability

1

2

0 500 1000 1500 2000 25000

Intensity (KN)


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0.01om ne ro a y ass or ruc oa n

ityMass

0 500 1000 1500 2000 25000

.

Probabil

Intensity (KN)

1Cumulativ Combined Probability Mass for Truck Load in TSY

bilityMass

0.5

lativeProba

0 500 1000 1500 2000 25000

Intensity (KN)Cumu


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1x 10

- ro a y ass or ar qua e oa n

ityMas

s

OriginalRe-Estimated

0 0.5 1 1.5 20

.

Probabil

x 104Intensity (KN)

1Cumulativ Probability Mass for Earthquake Load in TSY

bilityMass

Original

0.5

lativePro

be- s ma e

0 0.5 1 1.5 2

x 104Intensity (KN)C

um


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0.9

1Cumulative Probability Mass in TSY

0.6

0.7

0.8

bilityMass

0.4

0.5

ulativProb

0.1

0.2

.

C

u

A--Truck onlyB--Earthquake only

C--Truck & Earthquake

D--Truck & Earth.-Direct

0 500 1000 1500 2000 2500 30000

Intensity (KN)


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Progress Report


A major challenge in establishing multi-hazard LRFD equations is to provide a

simple process for the bridge designers.

One important task is to identify significantdesign limit status for a region vulnerable to

multiple hazard threat to that region.

A workshop was carried out for this purpose.

Worksho Steerin Committee: Harry Capers,John Kulicki, Thomas Murphy (Chair), George Lee

(coordinator), W. Philip Yen


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Progress Report (contd)


Questionnaire to all AASHTO bridge

bridges and special bridges)

AASHTO bridge engineers, FHWA officials,

bridge design experts and academic

researchers to consider the survey results. Formulate regional design limit states in the

US (work in progress).


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Progress Report (contd)

Sample Survey Results andSample Survey Results andPreliminary MessagesPreliminary Messages


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e ar se ar s yp ca r gesyp ca r ges

1No,0,

0%

2

Maybe,

2,6%

Scour VesselCollision Earthquake 3Always,2,6%

StormSurge

1No,9,

28%

3

Always,

10,31%

1No,7,

22%

2

3

Always,

16,50%

1No,

13,41%

2

Maybe,3

Always,

30,94%

2

Maybe,

13,41%

3Fire

30, 94% means: 30tates (94% ofespondent) gave this

Maybe,

9,28%

17,53%

Wind Debris Flow

2

Maybe,

10,31%

Always,

0,0%

. 1No,1,3%

2

Maybe,

10,31%

1No,5,

15%

3

Always,

5,16%

1No,

22,69%

3

Always,

21,66% 2

Maybe,

22,69%


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Combination of Scour and Debris FlowCombination of Scour and Debris Flow



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Potential Regional SimplificationPotential Regional Simplification


To make it practical in design using thelar e set of limit states a rocedure tochoose dominant limit states by region maybe developed.

I II III

I: High seismicity, non-hurricanecoastal wind

II: Lon -term hi h seismicit

Low temperature-related

issues

II

V

Inland windIII: Inland wind

IV: Hurricane zoneregionSpecialregion

V: Long-term high seismicity,

hurricane zone


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Potential Hazards in Each RegionPotential Hazards in Each Region


Region I:

Earthquake, non-extreme wind, scour, fire, and vehicular collision.Vessel collision is possible in some area.

Earthquake (long-term), non-extreme wind, scour, fire, andvehicular collision.

Region III:- , , , ,

collision. Northern central plain: debris flow (ice)

Region IV:Extreme wind (hurricane), scour, fire, and vehicular collision, and

.

Region V:Earthquake (long-term), extreme wind, scour, fire, and vehicularcollision, and vessel collision.

Special Region (NY, NJ, NH, DE, CA, ):Earthquake, non-extreme wind, scour, fire, vehicular collision,vessel collision, and blast.


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Preliminary MessagesPreliminary Messages


Geographical features and natural hazards

are substantiated.

Importance of cascading events for whichour knowledge for design is extremely

.

Unique features for NE and CA corridors with

consequence)

-

formulated for several regions.


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Next Step:Next Step:


Continue to address the major challengesor t e eve opment o - .

Continue to refine the regional designconcept and to establish a selected sets

of design limit state equations.

Workshop involving AASHTO, FHWA anddesign professionals to establish the

sets of design limit state equations.


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Development of Multiple Hazards Design GuidelinesDevelopment of Multiple Hazards Design Guidelines

To establish the LRFD guidelines for all-azar res ent, susta na e r ges s

complex and intellectually challenging.

equ res susta ne eve opment ymultidisciplinary team research efforts.

equ res sus a ne e uca on e or odevelop new generation engineers and - .


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Summary contdSummary contd

This lecture is only intended to provide

bridge engineering under early stage of

development to the students, as anexample of sustainable development in

bridge engineering.

The description of developing regionaldesign limit states of combined hazards

s researc curren y n progress. e

final outcome may be different.


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AcknowledgementAcknowledgement

Federal Highway Administration (funding)

Pro ect Research Team Or anizationsAurora & Associates, FHWA,

University at Buffalo, UC Irvine

UB Research Team

. . , . . . ,

scholars and graduate students


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.


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Review Quest ions

1. Why should bridge design include all hazards in order to satisfy

sustainability in bridge engineering?2. Wh is Education a si nificant com onent in sustainable

development?

3. Why are some aspects of current design specifications too

4. Do we know how to design a bridge with a capacity equal to or

slightly over the limit states?

. a s e ma or erence e ween owa e ress es gn

(ASD) and Load and Resistance Factors Design (LRFD)?

6. Probability (reliability) based formulation provides answers in

probabilitic terms. Design specifications are given as

deterministic limit state equations. How did this happen?

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