con strut ion and failure of bridges

8/2/2019 Con Strut Ion and Failure of Bridges

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BRIDGE CONSTRUTIONA

ND COLLAPSE


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HISTORY OF BRIDGES

Bridge is not a construction but it is aconcept, the concept of crossing overlarge spans of land or huge masses

of water, and to connect two far-offpoints. The bridge provides passageover the obstacle of small caverns, a

valley, road, body of water, or otherphysical obstacle. Designs of bridgesvary depending on the nature of theterrain and the function of the bridgeand where it is constructed.


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Ancient wooden bridge


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HISTORY OF BRIDGES

The first bridges were believed to bemade by nature as simple as a logfallen across a stream. The first

bridges made by humans wereprobably spans of wooden logs orplanks and eventually stones,

The Indian Epic literature Ramayanaprovides mythological accounts ofbridges constructed from India to Sri

Lanka by the army of Sri Rama, the


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HISTORY OF BRIDGES


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The recent satellite photograph depicts theexistence of this bridge, referred to in

Ramayana.


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Suspension bridges had been known in China asearly as 206 BC. Chinese built big bridges of wooden

construction, and later stone bridges


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The oldest surviving stone bridge in China is theZhaozhou Bridge built around 605 AD during theSui Dynasty.

This bridge is also historically significant as it is the worldsoldest open- stone segmental arch bridge.


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The ancient Romans were the greatest bridge builders .

They used cement, calledpozzolana consisting of water, lime, sand,and volcanic rock, which reduced the variation of strength found innatural stone.


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TYPES OF BRIDGES-

Simple bridges

The most primitive human

communities must often havecreated bridges from material lyingeasily to hand. Hunters and

gatherers follow favourite paths;streams need to be crossed. A fallentree can be dragged into position toserve as a plank.


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Roman bridges: 1st - 2ndcentury AD

Roman construction is the building ofbridges across rivers where no rockor island emerges from the water to

carry the piers. An example survivesin Rome - the Sant'Angelo bridge,built for Hadrian in AD 134 as an

approach to his great circularmausoleum.


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Inhabited bridges: 12th - 16thcentury AD

The greatest contribution of the Middle Ages tobridge building is the attractive notion of bridgeswith houses on them. This development has twopractical origins. In walled cities, where

accomodation is strictly limited, any firmfoundation for a building is valuable; and withwater mills a common source of power, a bridgewith a mill upon it serves two useful purposes.
http://www.historyworld.net/wrldhis/PlainTextHistories.asp?gtrack=pthc&ParagraphID=fmshttp://www.historyworld.net/wrldhis/PlainTextHistories.asp?gtrack=pthc&ParagraphID=fms


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IRON AND STEEL BRIDGESIron and Steel bridges are used today and most of the worlds major riversare crossed by this type. The picture shows the first iron bridge in the world.It was built in Telford in 1779 by Abraham Darby (the third) and was the first

large structure in history to be constructed from iron.


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SOME MODERN STEEL BRIDGESGirder bridges often carry railways and many were builtin the early part of the 20th century.

They are capable of carrying heavy weights. Usually theyspan short distances.

uspens on


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u - uspens onbridges are the cheapest way of spanninglong distances. Cables hold the road inposition.The Humber Bridge was once thelongest suspension bridge in the world


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Cantilever bridge-

A cantilever bridge has a deck (road) which is

supported at one end.The Forth Railway Bridge in Queensferry, Scotland is

made up of three cantilevers. It was finished in 1890and took eight years to build.


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CONSTRUCTION DETAILS OFBRIDGE

DESIGN OF BRIDGE COMPONENTSINCLUDES-

1.CALCULATION OF BEARING LOADS

2.DESIGN OF PORTAL PIER ANDFOUNDATION


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BEARING LOADCALCULATIONS

ELEVATION


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BEARING LOADCALCULATIONS

I. CALCULATE REACTIONS DUE TOSELF WEIGHT,DL & LL

II. CALCULATE ECCENTRICITY DUE TO

CURVATURE,IF ANY,BY -2/3*RADIUS*(1-COS)

III. CALCULATE MOMENT DUE TO

ECCENTRICITYIV. FIND OUT MOMENT DUE TO

ECCENTRICITY DUE TO ONE TRACK

LOADED


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MAX & MIN BEARING LOAD= vertical reaction

moment no. of bearings

bearing spacing


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DESIGN OF PORTAL PIER &OPEN FOUNDATION

i. LOAD CALCULATIONS

ii. FORCES CALCULATED ASEXPLAINED ARE APPLIED ON THEIDEALISED STRUCTURE IN STAAD-PRO

iii. FROM STAAD,FORCES ARECALCULATED ON FOUNDATION TOP

iv. CRITICAL LOAD CASES ARE MADEFOR DESIGN OF FOOTING


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DESIGN OF PORTAL PIER &OPEN FOUNDATION

xi. FOOTING SIZE IS CHECKED FORBASE PRESSURE

xii. FOOTING DEPTH IS CHECKED FORSHEAR AND REINFORCEMENT ISCALCULATED CORRESSPONDING TOBENDING MOMENT


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-

elevation


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In pier foundation as a base footing weuse M-15 lean concrete at foundationlevel.

plane

i f f i


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Reinforcement of pier

16mm

bars

32mm

bars

20mmbars


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3/31/12 ELEVATI

BOX FOOTING-its also

known as openfoundation

Earth isused tofill theseboxes

It indicatethereinforcement of box

wall withM30concrete

Base footing

with M15 leanconcrete

G.L.


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Reinforcement of box wall

Blank boxesin whichearth is filled

n r ge


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- n r geconstruction two types of retaining wallare used.

1.Strip type retaining wall

Curtailment ofreinforcement

Counterfort areused tosupport the

retaining wall


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WELL FOUNDATION

Well Foundation:

Well foundation is the most commonlyadopted foundation for major bridgesin India. Since then many majorbridges across wide rivers have been

founded on wells.

Well foundation is preferable to pile

foundation when foundation has to


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WELL FOUNDATION While deciding the bottom level of the

foundation the following considerationsmay be kept in view.

a. Normally, a sandy strata with adequatebearing capacity is preferred to a clayeystrata.

b. A thin stratum of clay occuring betweentwo layers of sand is not relied upon but

pierced through


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WELL FOUNDATION

SINKING OFWELL


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WELL FOUNDATION

Components:

A well foundation consists of the followingcomponents.a. Steiningb. Well Curbc. Bottom Plugd. Sand filling

e. Top Plugf. Well Capg. Cutting edge


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FAILURE OF BRIDGES Failure Analysis Of Mishap At DMRC O

It was 12th July 2009 which proved to bethe darkest day in the history of DMRC.After achieving a milestone of providing areliable and easy mean of transportationto the capital of India, it is now facinghuge problems which are not only

causing loss of human lives but alsocausing immense damage to the mostreputed infrastructure organization of

India.
http://www.engineeringcivil.com/failure-analysis-of-mishap-at-dmrc-on-12-july.htmlhttp://www.engineeringcivil.com/failure-analysis-of-mishap-at-dmrc-on-12-july.html


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Let us try understanding what went


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Let us try understanding what wentwrong on that disastrous day

On 12th July, 2009, while lifting segments of the

superstructure, an accident happened in the Badarpur Secretariat section near P-67. The pier cap of pier P-67got collapsed causing subsequent collapse of the(i) Launching Girder

(ii) Span between P-66 and P-67 which had got erectedand pre-stressed, already(iii) Segments of the superstructure for the spanbetween P-67 and P-68.

The incident left 6 people dead and many injured.

Crane Failure


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GIRDER FAILURE

CRANEFAILURE

The launching girder was lifted by the cranes. However, it needed to be pushedlittle forward forunloading it on the ground. So, all the cranes were asked to stretch therebooms by some length.During this operation, the 250 MT capacity crane on extreme left exceeded itscapacity and theboom failed and broke down. Since, there were unequal loading on the 250 MTcrane by its side,that also failed and broke down.

Final overview


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Final overview

a. It is concluded that the failure of pier cap occurred due toinadequate prop / jacket. This was coupled with failure of

cantilever pier cap due to inadequate development length of topreinforcement of the cantilever pier cap.

b. The failure of the crane was a case of operational inexperience

for such synchronized crane operation. The crane -1 did not havethe requisite capacity for the extended boom length and radius.

Once crane 1 failed, the crane 2 was loaded almost half of the

launching girder amounting to around 200 MT. For the extension ofboom and radius, it did not have the requisite capacity so it failed,too. The crane -3 was loaded more than its capacity. However, inthis case the crane got toppled instead of boom getting sheared.

The crane -4 did not undergo the severe loading due to failure ofother 3 cranes and most of the loads got grounded by that time.

,On August 1 2007 during the evening rush hour the main spans of


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,On August 1, 2007, during the evening rush hour, the main spans ofthe bridge collapsed, falling into the river and onto its banks. Thirteenpeople died and approximately one hundred more were injured. The1,907-foot bridge fell into the Mississippi River.

This structural failure was caused by joints of trusses (steelstructures) supporting the bridge slab were not welded to the full; thewelding thickness, which should be over 10mm, was only 8mm; andfurther, connecting pins for steel bolts were poor.

, . ,Thirty-three people are killed when a 150-year-old bridge being


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Thirty three people are killed when a 150 year old bridge, beingdismantled, crashed on the train near the Bhagalpur railway station inthe state of Bihar.

ay , . uns ne yway r ge or a,Th S hi Sk B id ll d M 9 1980 h th


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y , y y g ,The Sunshine Skyway Bridge was collapsed on May 9, 1980, when thefreighter SS Summit Venture collided with a pier (support column)during a storm , sending over 1200 feet of the bridge plummetinginto Tampa Bay. The collision caused six automobiles and a bus to fall

150 feet, killing 35 people.

Tacoma Narrows Bridge Collapse
http://www.engineeringcivil.com/tacoma-narrows-bridge-collapse.htmlhttp://www.engineeringcivil.com/tacoma-narrows-bridge-collapse.html


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Tacoma Narrows Bridge CollapseIt was an unfortunate morning of 7th November 1940 whenwinds having speed of 42 miles per hour suddenly twisted the

Tacoma Narrows Bridge and lead to its collapse. This accidentthough didnt look any lives but it surely made the civil

engineers to think new ways to combat bridge collapses
http://www.engineeringcivil.com/tacoma-narrows-bridge-collapse.htmlhttp://www.engineeringcivil.com/tacoma-narrows-bridge-collapse.html


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The bridge was designed by engineer Moisseiff who hadstrengthened it with a solid steel girder beneath the roadway.

But the problems started soon it was opened to traffic.Understrong winds, it swayed much beyond the permissible limits andthus sent rippling waves along the deck.

It took just 4 months before this bridge collapsed after itscompletion.

On investigating it was found that the solid steel girders providedto strengthen the bridge were actually blocking the wind whichcaused the bridge to twist.

Due to this a swirlin motion develo ed which ultimatel lead to


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What it taught us?

a. Structural designs should be proof

checked by experienced structuralengineer.

b. Once failure observed, structure should

be as far as practicable abandoned andnew structure should be built up

c. More emphasis should be given on

detailing of reinforcement to cater forconnections and behavior of thestructural components.

d. Any make-shift arrangement to save a


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THANK YOU

con strut ion and failure of bridges

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