ho final presentation evolution of bridge technology

ASCE/SEI Workshop, Washington DC, Feb.2008

EVOLUTION OF BRIDGE TECHNOLOGY

BYMAN-CHUNG TANG, Chairman of the Board

Presented byTom Ho, Vice President

T.Y. Lin International

1. What has been the most important factor in the evolution of bridge technology?

2. Would the Romans and the Egyptians be able to build our bridges if they had the construction materials of today?

Evolution:Human beings started building bridges many thousand years ago.

What made our modern bridges different from the ancient ones?

First of all,

What are our bridges made up of?

Let us look at the bridges we have today.

In the several thousand years since we started building bridges, we have built only

FOUR TYPES OF BRIDGES

In the several thousand years since we started building bridges, we have built only

FOUR TYPES OF BRIDGES

Girder bridgesArch bridges

Suspension bridgesCable-stayed bridges

Extradosed Bridge is a combination of girder bridge and cable-stayed bridge

We can have other combinations too

Partially cable-supported girder bridges.

Franz Dishcinger proposed this combination of

cable-stayed and suspension bridge

But, still only these four basic types.

All four types of bridges have existed for millenniums!

SUSPENSION

GIRDER

CABLE-STAYED

STRESS RIBBONCONT. BEAM

They were not as sophisticated.

But, conceptually correct nevertheless!

All four types of bridge have existed for millenniums!

SUSPENSION

GIRDER

CABLE-STAYED


They were not as sophisticated. But, conceptually correct nevertheless!

They build them

IntuitivelyEven before

we gave them a name.

All four types of bridge have existed for millenniums!

SUSPENSION

GIRDER

CABLE-STAYED


They were not as sophisticated. But, conceptually correct nevertheless!

They used Construction materials

available naturally!Wood, vines, stone, ropes,

etc.

Sad to admit, In the last few thousand years,

We have NOT invented any new bridge type.

Because we have not invented anything

It is an evolutionNot any revolution.

Because we have not invented anything

It is an evolutionNot any revolution.

But, our bridges today are

Bigger, stronger, more sophisticated, more durableand, more predictable.

Today’s bridges

Bigger, stronger,

more sophisticated,

and

more durable

CRAIGELLACHIE, 1815

What affects the evolution of bridge technology?

What affect the evolution of bridge technology?

Science - structural theoriesConstruction equipmentConstruction material

Look at these old, old structures


Structural theoriesConstruction equipmentConstruction material

?


Structural theoriesConstruction equipmentConstruction material ?

They did it empirically!



0204060

1stQtr

3rdQtr

WestNorth

Great Pyramid of Gaza2550 BC

Pyramid of Dozer2750BC



They made it work, somehow!

Material has been the most important factor in the evolution!


Creation of a bridge - A Flow Chart

A Flow Chart

Two Dominating Materials in the History of Bridge Construction are:

Stone

Steel

Dominating influence

&

Two main eras in bridge evolution:

Arch Era2000BC– 1850ADAlmost 4000 years

Contemporary Era1850AD - now Only about 160 years

Stone

Steel

&

2000

BC

Rom

an

Em

pire

Con

tem

pora

ry E

ra18

50 A

D

2008

AD

Arch Era

ARCH ERAStone

Up to two hundred years ago, the only construction material available was STONE.

STONE can take high compression,but very little tension.

Arch is the only bridge type that does not require tensile capacity of the material

The Romans built many spectacular

arch bridges


arch bridges

Over 2000 years ago!


arch bridges

The Roman arches are all semi-circular

Zhaozhou Bridge, ChinaSpan 37m, Rise 7m. Built 600AD

18.5m

37m

37m

7m

A Roman ArchZhaozhou Bridge

The first non-semi-circular arch bridge.

Semi-circular vs Segmental

7m

18.5m

The Romans were really masters on stone arches!

The Romans were really masters on stone arches!

But, for almost one and a half millennia after the Romans,

nothing new happened!

Contemporary EraFrom 1850 until now

Then came the


Only about 160 years. But there were more bridges built in these 160 years

than the 4000 years before it.


Iron & Steel

There was a transition period that we had IRON as construction material.

Iron is much stronger than stone, but its tensile capacity is still very limited.

There was a transition period that we had IRON as construction material.

Iron is much stronger than stone, but its tensile capacity is still very limited.

We may categorize iron as a primitive form of steel, as far as construction material is concerned.

The Chinese started building iron chain suspension bridges around 600 AD

A suspension bridge in Tibet

A bridge in Tibet

Coalbrookdale Bridge,Span 30.5mBy Thomas Pritchard, 1779

Dom Luis I BridgeBy Gustav Eiffel and Th. Seyrig,

1885, span = 172m

Iron arch bridges was popular for a period of time

Menai Bridge – the first major suspension Bridge

Designed by Thomas Telford, span = 176mbased on a patent by James Findley, completed in 1826.

With iron eye bar chains as main cable.

Menai Bridge – the first major suspension Bridge

Designed by Thomas Telford, span = 176mbased on a patent by James Findley, completed in 1826.

With iron eye bar chains as main cable.

B

SteelMass production processes were introduced in the mid 19th

century


centuryIt changed the entire landscape of bridge construction


centuryIt changed the entire landscape of bridge construction

Steel plates used for girders – boxes and trussesSteel bars for concrete reinforcement

Steel cold drawn wires for cablesSteel wires for prestressing


century

Three landmark steel bridge structures before the 20th century:

1. St. Louis Bridge by James Eads, 1874 2. Brooklyn Bridge by the Roeblings, 1883

3. Firth of Forth Bridge by John Fowler and Benj. Baker, 1889

The St Louis Bridge over the Mississippi.Completed 1874, Spans 153m + 158.5m + 153mDesigned by James Eads

The Brooklyn Bridge, New York CityCompleted 1883, Span 486m.Designed by John and Washington Roebling

The Firth of Forth Rail Bridge, Scotland.Completed 1889, Span 521m.Designed by John Fowler and Benjamin Baker

Then came

A tale of three bridges, in early 1900s……………………

Hell Gate Bridge, Sydney Harbor BridgeBayonne Bridge

The Hell Gate Bridge in New York by Gustav Lindenthal. Span = 298m.

Completed in 1916.

Sydney Harbor Bridge. Span = 503m by Ralph Freemann, Const. 1924 - 1932.

Bayonne Bridge in NY. By Othmar Ammann

Span = 503.6m Constr. 1928 - 1931

New River Gorge, USA, 1978Span = 518.3m

Lupu, China, 2004Span = 550m

Competition of Span LengthsSpan Year

Hell Gate, NY Gustav Lindenthal 298 1916Sydney Harbor Ralph Freemann 503 1932Bayonne, NY Othmar Amman 503.6 1931 New River Gorge, WV Michael Bakers 518.3 1978Lupu, Shanghai Lin Yuan Pui 550 2004Caotienmen, Chongqing 552 2008

Competition of Arch Span Length

0100200300400500600

1850 1900 1950 2000 2050Year

Spa

n Le

ngth

s (m

)

Hel

lgat

e

Syd

ney

Har

bor

Bay

onne

New

Riv

er G

orge Lu

puC

aotie

nmen

Pia

Mar

iaG

arab

it

St.

Loui

s

Luis

I

Long span suspension bridges

became possible only after high strength wire was available.

High Strength Steel Wire for Suspension Bridges

Some landmark suspension bridges:

Brooklyn 486m, 1883George Washington 1067m, 1931Golden Gate 1280m, 1937Verranzano Narrows 1298m, 1964Humber 1410m, 1981Storebelt 1624m, 1998Akashi Kaikyo 1991m, 2000

Golden Gate 1280m, 1937Verranzano Narrows 1298m, 1964Humber 1410m, 1981

Storebelt 1624m 1998Akashi 1991m 2000

Longest Suspension Bridge Spans

0500

1000150020002500

1800 1850 1900 1950 2000 2050Year

Span

Len

gth

(m)

Men

ai Bro

okly

n G. W

ashi

ngto

nG

olde

n G

ate

Ver

ranz

ano

Hum

ber

Sto

rebe

lt Aka

shi

Sar

ine

Val

ley

Longest Suspension Bridge Spans

0500

1000150020002500

1800 1850 1900 1950 2000 2050Year

Span

Len

gth

(m)

Men

ai Bro

okly

n G. W

ashi

ngto

nG

olde

n G

ate

Ver

ranz

ano

Hum

ber

Sto

rebe

lt Aka

shi

Sar

ine

Val

ley

Iron Steel

The two giants:

Messina 3,300mGibraltar 5,000m

High Strength Wires also made cable-stayed bridges popular


Because of the sag, cables must be stressed to a high force to be effective.

Consequently, cables must be highly stressed.


Because of the sag, cables must be stressed to a high force to be effective.

Consequently, cables must be highly stressed.

This means, cable wires must be very high strength.

Three World Record Spans within 60km.(Dusseldorf & Duisburg)Theodore Heuss 260m 1957Knie 320m 1970Neuenkamp 350m 1971

Longest Cable-Stayed Bridge Spans

0200400600800

10001200

1950 1960 1970 1980 1990 2000 2010 2020Year

Span

Len

gths

(m)

Stro

msu

ndTh

. Heu

ss

Leve

rkus

en

Kni

eN

euen

kam

p

Sai

n N

azai

re

Ann

acis

Yan

gpu

Nor

man

dy

Tata

ra

Sut

ong

High Strength Steel also made prestressed concrete bridges possible

High Strength Steel also made prestressed concrete bridges possible

Without high strength steel, prestressing is not effective.

Bendorf BridgeSpan 208m, 1962

Second Shibanpo BridgeSpan 330m, 2006

Two Significant Prestressed ConcreteBox Girder Bridges

CONCRETE GIRDER BRIDGES

0

50

100

150

200

250

300

350

1940 1950 1960 1970 1980 1990 2000 2010

YEAR OF COMPLETION

SPA

N L

ENG

TH (m

)

混凝土連續剛構跨度

“Concept of Structures“ by Man-Chung Tang,, 2003

年份

Milestone Segmental Bridges

0

50

100

150

200

250

300

350

1940 1950 1960 1970 1980 1990 2000 2010

YEAR

SPA

N L

ENG

TH (m

)

Balduinstein

Stolmasundet

KororBendorf

Worms

混凝土連續剛構跨度


Shibanpo

Gateway

LONGEST STEEL BOX GIRDER BRIDGES

0

50

100

150

200

250

300

350

1950 1960 1970 1980 1990 2000 2010

YEAR OF COMPLETION

SPA

N L

ENG

TH (m

)

钢箱跨度


年份

Effect of Materials on Evolution of Bridge Technology

Wood - timber bridges, short spansStone - arch bridges, longer spansIron - early suspension bridgesSteel - long span girder bridgesSteel wires - long span suspension bridges

- cable-stayed bridges- prestressed concrete bridges

Evolution:1. What was the most important factor in

the evolution in bridges?

2. Would the Romans and the Egyptians be able to build our bridges if they had the construction materials we have?

Evolution:1. What was the most important factor in

the evolution in bridges?

2. Would the Romans and the Egyptians be able to build our bridges if they had the construction materials we have?

Obviously, no one knows. But let us take an example.

Aerodynamics

Most early suspension bridges were failed by wind.

Around 1800, James Findley patented the stiffened suspension bridge.

Most of those bridges were destroyed by wind.

Aerodynamics

Most early suspension bridges were failed by wind.

Around 1800, James Findley patented the stiffened suspension bridge.

Most of those bridges were destroyed by wind.

Around 1870, John Roebling installed inclined cables in Wheeling Bridge to help mitigate wind vibration problems. It worked!

He found a solution in less than 70 years.

Aerodynamics

Most engineering solutions came before the theory.

Engineering is an art, not a science!

Most engineering solutions came before the theory.Engineering is an art, not a science!

And,

Looking at how the Egyptians, the Romans and the Chinese built their spectacular structures,

Structural theories and modern equipments do not seem that important.

Most engineering solutions came before the theory.Engineering is an art, not a science!

To answer my second question, I may dare say that given the materials we have today,

The Romans and the Egyptians would most probably be able to build our bridges too!

ButEvolution of bridge technology can only happen if we have the opportunity to build bridges.


Two pre-requisites determine if a bridge will be built:

1. Affordability2. Necessity




Cost vs. Value

COSTS:

Planning

Right of Way

Construction

Maintenance

Others

VALUE:

Functional value

Community Value

Political Value

Aesthetic Value

Others

<=>

NO!

YES!

COSTS:

Planning

Right of Way

Construction

Maintenance

Others

VALUE:

Functional value

Community Value

Political Value

Aesthetic Value

Others

<=

COSTS:

Planning

Right of Way

Construction

Maintenance

Others

VALUE:

Functional value

Community Value

Political Value

Aesthetic Value

Others

<=

Related to the Living Standard.

Related to Construction cost index.

COSTS:

Planning

Right of Way

Construction

Maintenance

Others

VALUE:

Functional value

Community Value

Political Value

Aesthetic Value

Others

<=

Related to the Living Standard.

Related to Construction cost index.

As our society progresses,

the living standard usually increases faster than the construction costs.

That means, some bridges we can not afford today may become affordable tomorrow.




That also means, we will be building bigger and bigger bridges, as time goes by!




That also means, we will be building bigger and bigger bridges, as time goes by!



Good news for us bridge engineers!




When do we need a new bridge?

Periods with Great Opportunities: The expansion of the Roman EmpireThe industrial revolutionThe re-construction after World War IICurrently, in China, India and other developing countries.



Periods with Great Opportunities: The expansion of the Roman Empire - Stone Arch BridgesThe industrial revolution - Steel productionThe re-construction after World War IICurrently, in China, India and other developing countries.


The Expansion of the Roman Empire - Stone Arch BridgesThe industrial revolution - Steel productionThe re-construction after World War II -

cable-stayed bridges, orthotropic decks, prestressed concrete bridges, composite decks


Periods with Great Opportunities:The Expansion of the Roman Empire - Stone Arch BridgesThe industrial revolution - Steel productionThe re-construction after World War II -


Currently, in China, India and other developing countries.?


Periods with Great Opportunities:The Expansion of the Roman Empire - Stone Arch BridgesThe industrial revolution - Steel productionThe re-construction after World War II -


Currently, in China, India and other developing countries.

We will see !

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China vs. USA

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苏通大桥第五次专家论坛正交异性板钢桥面的一个新构思林同棪国际 -邓文中

Currently, we have new materials with very high strength: composites, HPC, etc.

What kind of evolution in bridge technology will they bring us ?

My last question today:




They say, We can predict the future based on the past!




They say, We can predict the future based on the past!

For Example…….

IN RUSSIA

History may offer good hints for the future!

IN RUSSIA

HAIRY

Here is a historic record of HAIR.

BALD HAIRY

HAIRY HAIRYBALD BALD BALD

Obviously the next President must be a hairy one!!



We know they will definitely enhance the bridge performance, but would they bring out now bridge types?

Let us forget about the hairs …..



Coming back to My last question today:

Well, this is the homework for the future generations of engineer,

because I still have no idea!

Thank You!

ho final presentation evolution of bridge technology

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