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Objekttyp: Issue

Zeitschrift: IABSE structures = Constructions AIPC = IVBH Bauwerke

Band(Jahr): 12(1988)

Heft C-47: Repair and rehabilitation of bridges: case studies II

Erstellt am: Nov 29, 2013

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IABSE PERIODICA 4/1988PERIODICA AIPCIVBH PERIODICA

November 1988

ISSN 0377-7286J\IABSE STRUCTURES C-47/88

CONSTRUCTIONS AIPCIVBH BAUWERKE

Repair and Rehabilitation ol Bridges -Case Studies IIReparation et restauration de ponts -Exemples concrets IIInstandsetzung und Sanierungvon Brcken - Fallstudien II

International Association for Bridge and Structural Engineering IABSEAssociation Internationale des Ponts et Charpentes AIPCInternationale Vereinigung fr Brckenbau und Hochbau IVBH

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Editor - Publisher - AdvertisingRedacteur - Editeur - AnnoncesRedaktion - Herausgeber - InserateIABSE - AIPC - IVBHETH-HnggerbergCH-8093 Zrich, SwitzerlandTel.: (Int+ 41 1)377 26 47Telex: 822 186 IABS CHTelegr.: IABSE, CH-8093 Zrich

Papers published under the sole responsibility of the author(s).Les articles sont publies sous la seule responsabilite de (des) l'auteur(s).Die Artikel werden unter der alleinigen Verantwortung des oder der Autoren verffentlicht.

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IABSE PERIODICA 4/1988 IABSE STRUCTURES C-47/88 65

Repair and Rehabilitation of Bridges - Case Studies IIReparation et restauration de ponts - Exemples concrets IIInstandsetzung und Sanierung von Brcken - Fallstudien IITable of Contents - Table des matieres - Inhaltsverzeichnis

1. Reparation du pont Tembembe (Mexique)2. Repair of Scoured Substructure (Japan)3. Rehabilitation of Prestressed Concrete Bridge Deteriorated by Salt (Japan)4. Rehabilitation of Wakamiya Railway Bridge (Japan)5. TIG Are Remelting as a Repair Method for Steel Railway Bridges (Japan)6. Ohara Bridge Fatigue Crack Repair (Japan)7. Fujigawa Bridge Rehabilitation Project (Japan)8. Strengthening of Bridge Slab at Kami-Imasu Bridge (Japan)9. Rehabilitation of a Lenticular Steel Truss in New Jersey (USA)

10. Repair and Rehabilitation of Roma-Viterbo Railway Bridges (Italy)11. Repair of the Todsburg bridge (Fed. Rep. of Germany)

Page6668707274767880828486

IABSE STRUCTURES - Publication Programme in 1989PublicationFebruary 1989

May 1989

August 1989

November 1989

IABSE members are invited tocontribute to this series IABSESTRUCTURES Guidelines for preparing contributions are available atthe IABSE Secretariat.

ThemeStructures in PortugalConstructions au PortugalBauwerke in PortugalStructures in Sanitary EngineeringStructures en genie sanitaireTragwerke im SiedlungswasserbauRecent StructuresConstructions recentesNeuzeitliche BauwerkeArchitectural Concrete for FacadesBeton architectural et fagadesBeton in der Fassaden-ArchitekturLes membres de l'AIPC sont invites preparer une contribution pourcette serie CONSTRUCTIONS AIPC.Des directives pour la preparationdes contributions peuvent etreobtenues au Secretariat de l'AIPC.

Editorial Deadlinein IABSE SecretariatNovember 1, 1988

February 1. 1989

May 1. 1989

August 1, 1989

Die IVBH-Mitglieder sind eingeladen, einen Artikel fr diese ReiheIVBH BAUWERKE zu unterbreiten.Richtlinien fr die Vorbereitung derBeitrge knnen beim Sekretariatder IVBH bezogen werden

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66 IABSE STRUCTURES C-47/88 IABSE PERIODICA 4/1988

1. Reparation du pont Tembembe (Mexique)Maitre d'ouvrage: Secretaria de Communica-ciones y Transportes (SCT)MexiqueBureau d'etudes: Euro Estudios de MexicoEntreprise generale: Freyssinet de MexicoDuree des travaux: 4 moisExecution: 1987 - 1988Quantites mises en ceuvreResine d'mjection 200 kgPerforations par percussions 160 mPerforations outil diamant 30 mCbles 12 T 13 5700 kgCbles 12 O 7 580 kgCbles 1 T15 1300 kgAcier beton 10200 kgBeton 76 m3Mortier sans retrait 2000 IJoint de Chaussee Mex T50 17mLocalisationSitue l'ouest de Mexico sur la route peage Mexico-Acapulco, le pont Tembembe franchit un ruisseau entreCuernavaca et Taxco. C'est un ouvrage de 75,50 m,constitue de 3 travees.II recoit journellement 4500 vehicules legers et lourdsreliant le centre siderurgique de Lzaro Crdenas auxregions sud et est du pays

OuvrageConstruit en 1954, l'ouvrage en beton arme etait prevupour des cas de Charge HS15 (camions de 24,5 t),aujourd'hui, il ne correspond plus ni au trafic dont levolume s'est fortement accru, ni aux charges de lanouvelle reglementation AASHTO T3 S3 qui autorise descamions de 46 tUne visite d'inspection a permis de noter sur cet axeroutier des defauts sur divers ouvrages et en particuliersur le pont Tembembe o furent detectes- des fissures de flexion et d'effort tranchant sur lesnervures du tablier,- des fissures verticales dans les diaphragmes trans-versaux,- des articulations de cantilever bloquees,- des fractures en zone d'appui de cantilever consecu-tives au non fonctionnement des articulations,- des defauts de betonnage sur talons de poutres,- les murs garde-greve casses par blocage des joints dedilatation

VSection transversale

2 500

2 500 2 500

mxTirr^k \}\Alax\-/^\ ^Itz^Dinj^zJi77777

Section longitudinale, avant reparation

h77977

45Q0 2 500 2 500

iLtrtHttrtft777777

Section longitudinale, apres reparation

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Etude11 fut decide de transformier la structure discontmue enune structure continue pour faciliter la mise en ceuvre dela precontrainte exterieure et cause de la mauvaiseexecution des appuis cantilever qui rendait difficile lareparation sans interrompre le traficUn deficit de moment resistant de la section de 240 tm,a conduit a projeter la reparation sur la base de 3 cblesexteneurs Continus de 12T13 par nervure. disposesentre les nervures et devies sur les diaphragmesChaque diaphragme a du etre renforce par 4 cblesexteneurs 12 0 7 sous game en Polyethylene hautedensite (PEHD) injectes de coulis de cimentLes efforts tranchants furent repris par des etriers tendus en toron 1 Tl 5 devies sur les talons de poutre pardes selles beton Le hourdis superieur fut augmente de12 cm, les appuis dimensionnes en fonction de la nouvelle conception, ainsi que les joints de dilatationRealisationLes travaux furent realises sans Interruption de trafic enreduisant l'ouvrage a une voieToutes les Operations preliminaires la mise en ceuvrede la precontrainte exterieure de renforcement. c'est--dire les Operations d'injection des fissures la resine, lesforages, la pose de la precontrainte transversale, la posedes selles d'etners, le gainage et le montage des cbleslongitudinaux, furent realisees sans interrompre la circulation II y eu une Interruption complete du trafic durant 2jours pour injecter le mortier sans retrait des joints decantilever et tendre les cbles longitudinaux La dureedes travaux fut de 4 mois (Christian Tourneur)

t.^ %-Precontrainte exterieure de renforcement- Cbles longitudinaux et etriers tendus.

mf-

S***18Vue generale apres travaux de renforcement.Precontrainte verticale par etriers tendus.

3' ^'z %

-.sfiS. /

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2. Repair of Scoured Substructure (Japan)From the topographic features of Japanese rivers that oftenhave strong current from its gradient, river beds aroundsubstructures are often scoured For this reason, there is anecessity for repair and reinforcement of substructures Due

to limited duration of work possible, that is mostly duringwinter when the water level is low, and the limited clearanceavailable below the bndge, the methods for repair that canbe taken are limited Following are two cases

Case 1 Reinforcement with piles; Iwaide Bridge, WakayamaOwner:Contractor:Work's duration:Date of repair:

Ministry of ConstructionKoike Gumi, Asakawa Gumi6 months1979 - 1980The Iwaide bridge, completed in 1955, has 385 m bridgelength and 7.5 m road width (Fig. 1). The substructureconsists of a 13 span cantilever girder. The substructureis a wall type reinforced concrete pier and an ellipticalopen caisson foundation of a length from 10.0 m to12.5 m.

The substructure has been scoured to a depth of 4 maverage up to 6 m maximum from the effects ofdredged riverbed and embankment located upstream. Inthe worst case, the depth of embedment was reducedto 5 m from the original 11 m. To prevent a furtherdecrease, measures were taken in 1970 by temporarilyplacing protection blocks. Then in 1979 the caissonswere checked again for its stability To completely solvethe problem, the substructure was reinforced by under-pinning and construeting a new slab connected with theexisting caisson The repair Job was performed on 7heavily scoured substructures among a total number of12.For reinforcement of caisson with reduced depth ofembedment, a cast in place pile method was chosen forunderpinning, under consideration of geologic condition,clearance below girder during work an economyWith the cast in place piles, four Benoto piles of 1 5 mdiameter and 11.5m length were placed at four sides ofthe caisson. The caisson and piles were connected byplacing a 2 m thick slab on top to make a new footing(Fig. 2 and 3). To determine the dimension of slab andpiles, the structure was analysed to resist workingforces together with the existing bridge. The caissonand slab was connected by having the upper and lowersteel reinforcements from the slab of 29 mm diameterand 3.5 m length embedded 30 cm deep with resin intothe sides of the caisson

'. c Z'-y HS

slab slabpi le pile

Fig. 2 Repair method (Iwaide Bridge)

SsF:

HJH

Fig. 3 After repair (Iwaide Bridge)_.. iuflaimamOO. t-f| JM AiaL IQtOQ tan |JM JJ JflKP l'itt ' *j*2 Jtaa. too

IMI % IMFig. 1 Elevation (Iwaide Bridge) iS 0

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Case 2 Repair by reinforced concrete lining; Natori Bridge, MiyagiJ90 800

o ZlZOCQJOJXB

Jl iii l

il X \vll reinforced concrete lining

I /Jcement paste groutingnn- footing protectionlern

Fig. 4 Location of repair (Natori Bridge)Owner:Contractor:Work's duration:Date of repair:

Ministry of ConstructionEndo Constructionphase 1: 5 months,phase 2:2 years and 1 monthphase 1: 1974- 1975phase 2: 1981- 1983

The Natori bridge, completed in 1932, has 190 8 mbridge length and 7.5 m road width (Fig. 4) The superstructure is a 9 span steel plate simple girder Thesubstructure consists of a rigid frame reinforced concrete pier and caisson.The substructure on this bridge was repaired due to thefollowing problems:1) Exposed steel reinforcements at top of the caisson.2) Bridge pier endangered of toppling due to scounng atthe caisson causing differential settlement and loss

of strength in the surrounding foundation.3) The connection between caisson and pier has beendeteriorated from shear force.4) Furthermore, due to its old design, its ability to resisttoday's load has been questioned.The repair job was carried out in two phases. Phase 1was the repair job on severely damaged piers and phase2 was for the remaining piers.The repair job was carried out by following four methods(Fig 5, 6 and 7):1) The bridge pier structure was repaired with a reinforced concrete lining added as a seismic protectionwall2) The caisson was reinforced by connecting the top of

the caisson with a connecting beam and adding areinforced concrete lining to its exterior.3) Cement paste grouting of foundations surroundingthe caisson4) To protect the pier from scounng, piers located onthe minor footing Protections were placed and forpiers located on the major bed. sheet piles wereplaced.This repair Job was carried out under limited clearancebelow bridge girder and had to be done during the dryseason In view of these conditions, the methodsdescribed above were considered to be effective in thisrepair Job. The reinforced concrete lining was economical and the required duration of work was short. Thecement paste grout has greatly increased the bearingcapacity of the foundation and was also found to beeffective in the river bed. (Norio Morinaga)

gyjo e25d, Q soc Z--*0%k

/zu

' .,< yreinforced concrete liningFig. 5 Repair method (Natori Bridge)

,, /r-

Fig. 6 Before repair (Natori Bridge)

' ''..

*a-Fig. 7 After repair (Natori Bridge)

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3. Rehabilitation of Prestressed Concrete Bridge Deteriorated by Salt (Japan)All structures located on the coastlme are likely to be sub|ectto damage by blown saltEven the prestressed concrete structures conventionallysaid to be maintenance-free are damaged by blown saltCase 1 Nadachi Bridge, NiigataOwner:Engineer & Contractor:Work's duration:Date of repair:

Ministry of ConstructionKawada Construction7 months1982 - 1983

The Nadachi bridge is a T shaped prestressed concretesimple girder bridge, completed in 1962 The bridge is70 m long consisting of three 22.7 m span and has a7 7m road width.According to inspection test carried out in 1982, cracksand Stripping were discovered mainly along the longitudinal reinforcements of the main girder lower flange.Corrosion seepage from these cracks and Stripping werenoticed at many places. These are the typicai characteristics of damages on most concrete structures in thearea affected by blown saltIn planning the work, the rehabilitation procedure wasreviewed based upon the following two concepts:a) the procedure should be capable of preventingfurther permeation of salt and moisture into thestructure and of slowing down or restricting the rate

of progress of damages to a minimum, andb) the procedure should be capable of rehabilitating thedeteriorated girder sections which have fallen off orcracked.Based on the above. it was deeided to coat anti-corro-sive paints to the whole of this bndge to cope with a),and also to rehabilitate the deteriorated member sections to their original design dimensions by adjusting thesurface evenness of girders and by repairing themember sections with resin mortar or resin concrete tocope with b)In the actual rehabilitation procedure, the cracked concrete portions, portions with corrosion seepage andstripped portions (these areas have lost their strengthand were acting only as loads on defected girders) wereremoved, then salt and debris stuck to the surface ofsteel members and concrete were removed by sand-blasting In addition, a modified epoxy resin paint wasapplied to the surface of steel reinforcements andcbles, then the concrete that was lost was restoredEpoxy resins were used for rehabilitating the concrete.Porous concrete surfaces and uneven portions werecorrected by epoxy resin mortar mixed with sand; tomake a good surface for paints. Epoxy resin prepackedconcrete method was adopted for continuous or largesections that had fallen off. In this case formwork wasattached and filled with dry aggregate and then epoxyresin grout was applied.Upon completion of the rehabilitation of sections performed as stated above, an anti-corrosive paint wasapplied to prevent corrosive materials from penetrating.

and recently, rehabilitation works for maintenance of thesestructures have been startedTwo cases of rehabilitation for a prestressed concrete roadway bridge deteriorated by salt will be explained hereafter

zuni**msSMrMBx**-il73T

I* HBtUSAtttFig. 1 Detonation of flange (Nadachi Bridge)

\Fig. 2 After repair (Nadachi Bridge)In applying anti-corrosive paints to these concrete structures having the normal surfaces not treated with paint,there were many unknown points, and it was thought tobe important to conduet a research on the suitable kindsof anti-corrosive paints. Thus, four kinds of paints shownin Table 1 were applied to the rehabilitated bridge.Generally, for a structure into which salt has alreadypenetrated, the sahnity will vary depending on the location of the portion to be painted, so that the effect ofpainted material varies by the location. Thus the effect atdifferent places cannot be compared on the same basis.Therefore, concrete slabs painted with four differentkinds of paints and unpainted concrete slabs wereexposed below this bridge (Fig. 1 and 2).Effect of these painted materials will be confirmed byexamining the atmospheric exposure test samplesseveral years later. (Shoji Miyazaki)

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flake glass epoxy paintNo paint System quantity (kg/m2) stage of work

1 epoxy pnmer 0 15 pnmer2 epoxy putty 0 40 putty3 flake glass mixed epoxy 0 90 2nd4 flake glass mixed epoxy 0 90 3rd5 urethane 0 J5 4th6 urethane 0.15 finish

flake glass vinylester paintNo paint system quantity (kg/m2) stage of work

1 epoxy pnmer 0 15 pnmer2 flake glass filledvinylester resin putty 0 40 putty3 flake glass filledvinylester resin 2nd 1 00 2nd4 flake glass filledvinylester resin 3rd 1 00 3rd5 urethane 0 15 4th6 urethane 0 15 finish

glass cloth reinforced non solvent epoxy paintNo paint System quantity (kg/m2) stage of work

1 epoxy pnmer 0 15 pnmer2 epoxy putty 0 40 putty3 F R P Ist 2 00 2nd4 F R P 2nd 1 00 3rdb urethane 0 15 4th6 urethane 0.15 finish

soft type non solvent polybutadien paintNo paint System quantity (kg/m2) stage of work

1 epoxy pnmer 0 15 pnmer2 epoxy putty 0 40 putty3 polybutadien 0 80 2nd4 polybutadien 0 70 3rd5 urethane 0 15 4th6 urethane 0 15 finish

Table 1 Paint list (Nadachi Bridge)Case 2 Oyataroh Bridge, MiyazakiOwner:Contractor:Work's duration:Date of repair:

Ministry of ConstructionFuji P.S. ConcreteSho-Bond Construction1 year1985 - 1987

The Oyataroh bridge is a T shaped prestressed concretesimple girder bridge, completed in 1975. The bridge is116.9 m long consisting of four span and has a 10.0 mroad width.The inspection carried out in 1985 revealed damagestypicai of salt deterioration such as cracked concretealong the transverse reinforcement at the lower flangeof main girders, concrete Stripping and rust. Furthermore, inspection by breaking the concrete revealed thatin some cases 2 cbles were broken among the 12cbles that are usedThe same repair method was applied as for Nadachibridge Cracked or stripped concrete areas wereremoved, sandblasted, resin paint applied on steel andconcrete restored to its original dimension with epoxyresin mortar by the prepacked concrete method. Torepair broken cbles, reinforcement methods by addingexternal cbles were studied. Considering the presenttraffic and other conditions of this bridge, it was deeidedthat the present strength is sufficient and that furtherreinforcement will not be needed.The anti-corrosive paint applied is as follows: the firstcoat is epoxy resin pnmer; second, third and fourth coatis polybutadien resin paint; finish coat is Polyurethaneresin. (Norio Morinaga)

\

Fig. 3 Crack at lower flange (Oyataroh Bridge)

-?Fig. 4 After repair (Oyataroh Bridge)

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4. Rehabilitation of Wakamiya Railway Bridge (Japan)

Owner: Central Japan Railway CompanyEngineer: Central Japan Railway CompanyRailway Technical Research InstituteWork's duration: 3 monthsService date: March of 1972 for up-bound lineThe article describes the rehabilitation of a railway concrete slab girder bridge with double reinforcement byrigid concrete frame.IntroductionTokaido Shinkansen line is a representative railway linein Japan where the trains are operated at a maximumspeed of 220 km/h. Since the beginning of the service in1964 more than 2 billion passengers have been transported on this line.All along the track, many types of concrete bridges havebeen constructed to overpass or underpass roads eteConcrete slab girder bridges with double reinforcement,which is profitable to decrease the depth of the girder,were planned to cross roads etc. with a span rangingfrom 7 to 15 meters. About 370 slab girder bridges ofthis type, were constructed. The stress and deflection ofthe bridges under the action of train load are larger thanthose of reinforced concrete of other types, becauseboth the depth and the rigidity of slab girders are smallerthan those of concrete bridges of other typesAfter about 4 years from the beginning of the service, aconsiderable increase in deflection of the bridges wasmeasured and many cracks appeared on the bottomsurface of the bridges. After checking these bridgesseveral considerably damaged bridges were reinforcedby increasing the rigidity.Situation prior to rehabilitationThe Wakamiya bridge (Fig. 1). located at 439 km fromTokyo, was damaged as follows:1) The bridge deflected vertically from 3.5 mm to4.7 mm at the center of the span under a test train

load. The ratios of deflection to span length are1:2,860 and 1:2,130 respectively. These ratios arenearly equal to the specified valueCenter of trackup-bound hne

measured in I968 measured in I970

I c unit mm)21 li* \n

111 - * ninn *.i. tw LJ?5P05200 1800

XX?%\ /J ~^X: :

To Tok/st

1

to shm-Osaka

-q=_-

:q=f |SfX

Center of girderFig. 1 Section of the girder of Wakamiya Bridge

Fig. 2 Crack distribution on the concrete surface of agirder of up-boundline2) The maximum width of cracks on the surface of theconcrete grew to 0.2 mm but most of them were0.1 mm wide Cracks opened on average by0.04 mm under train load and returned by 0 01 mm3) The crack distributions on the concrete surface inJune 1968 and in October 1970 are shown in Fig 2The number of cracks under repeated loading

increased in about two years.4) The ratios of the measured stress and deflectionunder test train loading are shown in Fig. 3 wherethe deflection ratio is the value of the deflection atthe center of the span at each speed of test train tothe value of the deflection at the speed of 158 km/hThe maximum increasing ratio amounts to 1 .7, whilethe specified value is 1.43.Cause of damage and measures adoptedThe cause of damage seems that the frequency of thebridge Vibration under repeated train loading approachedthe natural frequency of the bridge and that theresonance of the bridge was induced The resonanceseemed to have increased the deflection and to havecaused many cracks.The countermeasure to this damage is to avoid theresonance of the bridge. This is attained by setting theparameter v/2fl equal to less than 1/3, where v: trainspeed, f: natural frequency of the bridge and I: spanlength. As the natural frequency increases according tothe increase of the cross section of the bridge, it ispossible to avoid the resonance. In the case ofWakamiya bridge, the slab girder was strengthened by aconcrete rigid frame. The general view of reinforcedWakamiya bridge is shown in Fig. 4.As the result of this reinforcement, the deflection wasreduced to half of the original bridge. On TokaidoShinkansen line, 8 girders of 4 bridges were improved bythe same rehabilitation method.

(Y. Masuda, Y. Miyamoto)

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e i30

60O O 12 O O IZ0 2A A tr iL (2a. & 3

0 O (4,50X x 6

no ttress oftress ofreinforcing bor deflection:oncrete

20

fili3I0090 I60 I7D I80 I90 200 I60 ITO 180 190 200 160 170 180 190 200

Train speed (km/h)Fig. 3 Relationship between ratio of average measured value and train speed

J360 300* tir* 10700

\ inject ion ofY 450

IBFB

IOCX 1920 2500

(unit mm)300 1360

W^/////////^/////////Mon adhesive agent

9300

i^&//450

//w?

2500 .1920 POOFig. 4 Genera/ view of reinforced Wakamiya Bridge

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5. TIG Are Remelting as a Repair Method for Steel Railway Bridges (Japan)

Central Japan Railway Co.Central Japan Railway Co.Railway Technical ResearchInstitute19641987

Owner:Engineer:Date of Construction:Date of Repair:IntroductionThe fatigue cracks are occasionally found at the stress-concentrated parts of main member of steel railwaybridges. The fatigue crack in web plate that developed atthe toe of filled welded Joint of stiffener end is one ofthese kinds of cracks and Tungsten Inert Gas(TIG) areremelting was adopted as one of the effective repairmethods.Description of bridges and crackingThe Tokaido Shinkansen Line, 515 km long, whichstarted Operation in 1964, has approximately 1500 steelbridges.Fatigue cracks have been detected at the toe of filletwelded joints of stiffener ends in the web plates ofstringer beams of truss bridges and box section plategirders (see Fig. 1). The first fatigue crack was found in1975. The rates of the number of bridges having cracksdetected to that of the same type of bridges are sevenpercent for truss bridges and five percent for boxgirders.All these cracks were initiated at the stiffener end andthe schematic of crack propagation was shown in Fig. 2.Repair methodIn the conventional repair work, the fatigue crack formedat the stiffener end used to be removed by are airgouging and re-welded, then additional steel plates wereattached in that part using high-strength bolts. However,as this method was expensive, a more economical andeffective method was requested

Even if the fatigue crack is not formed at these parts, it isdesirable to decrease the possibility of initiation of crackby increasing the fatigue strength of filled welded jointThe TIG are remelting method shown in Fig 3 is adoptedfor the above-mentioned reasons.The TIG are remelting is a method of melting the toe offilled welded Joint with nonconsumable tungsten elec-trodes. In order to repair the fatigue crack by TIG areremelting, it is necessary to obtain the deep fusion andto smooth the toe shape. The conditions for TIG areremelting, as shown in Table 1, were set up based onthe results of preliminary tests.

Fatigue strength improved by TIG Are remeltingFatigue tests were performed to confirm the effect ofthis treatment on improvement of fatigue strength. Thefatigue strength of a Joint subjeet to TIG are remeltingwas much higher than that of an as-welded Joint asshown in Fig 4.

Crack in Box Girder==l^ Crack in Stringer

Fig. 2 Schematic of Crack PropagationStringer ofThrough Truss Bridge Box section Plate Girder Bridge

Fatigue Crack

Fatigue CrackFig. 1 Fatigue Crack at Stiffener End

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Fillet WeldTIG Are Regelung \

Electrode diaieter 3. 2.iCurrent 2 4 0 AVoltage 1 3~ 1 4 V( are length 0-1 )Speed 4 5-6 0 s/100Aiung Position 0 to 1 fn the toe of weldTorch angle 9 0

Fig.3 TIG Are Remelting Table 1 Condition of TIG Are Remelting400300

200

100

sa

- As-weldedGA GBO GC TIC (Vertical Position)GD TIG (Fiat Position)

foJ

Hi l l 107

Fig.10J 10

4 Results of Fatigue Test

Repair workRepair works for fatigue cracks at the stiffener end wereperformed to approximately 300 box girders along theTokaido Shinkansen Line.In the repair work, toes of fillet welded joints wereinspected first with the magnetic particle testing. If nocrack was indicated or the crack size was indicated asless than 10 mm, TIG are remelting was simply performed. When the crack size was more than 10 mm, thecracks were firstly removed by are air gouging and re-welded, then the toes of the re-welded joints wereremelted by TIG are. If the crack size was very large,additional steel plates were attached after re-welding(Y. Masuda, K. Sakamoto)

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6. Ohara Bridge Fatigue Crack Repair (Japan)

Owner:Engineer & Contractor:Work's duration:Date of repair:

Toyama PrefectureKawada Industries6 months1984 - 1985

The Ohara Bridge is a two-hinged arch bridge with thebridge span of 106 5 m and the roadway width of 6.0 m,completed in 1963 (Fig. 1). This bridge was designedwith the longitudinel support condition as being movableat both ends and had a Single box construction with archribs having a very small depth. After the elapse of morethan 20 years since its erection, fatigue cracks occuredin parts of the members of this bridge, mainly due toincreased traffic volume in recent years and frequentpassage of heavy motor vehicles associated with damconstruction work. Therefore, this bridge was repairedto reinforce the members against loads.The fatigue cracks occurred at the connecting gussetplates to each panel of intermediate post, whichconnects the stiffening girder to arch rib (Fig. 2, 3), andalso at the web of stiffening girder above end post,which is the Joint between center span and side span(Fig. 4, 5) These cracks were found by Visual inspectionduring patrol in 1982.According to the results of liquid penetrant testsconducted immediately after finding them, themaximum length of the cracks was 65 mm at the gussetplate of intermediate post, respectively 185 mm at theweb of stiffening girder.Among these cracks, a temporary repair was made forthe cracks in the web of stiffening girder immediatelyafter finding them in order to prevent a rapid breakdownas explained below. That is, stop holes were drilled atthe end of all cracks in the web. Moreover, steelbrackets were installed on all end posts and were usedas temporary supports for stiffening girders in side spanand center span.

StiffeninggirderwIntermediatepost

0 Locationof crack

iArcht M rib

Fig. 2 Location of crack

Fig. 3 Crack at gusset

250 .10 500 B5 000 10 500 250

B5 300 n

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Main girderCrack

V

2.500kg/on-StiffeninggirderCrackJL

End postFig. 4 Location of crack

* -*'

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7. Fujigawa Bridge Rehabilitation Project (Japan)Owner:Contractor:Substructure:Deck remplacement:Superstructure:Work's duration:Date of repair:

Shizuoka PrefectureSumitomo ConstructionJapan BridgeYokogawa Bridge Works6 months1987 - 1988

The Fujigawa Bridge, completed in 1924, over the FujiRiver on Route 1 is a bridge with six-span curved chordpratt truss having a bridge length of 300 1 m, roadwaywidth of 7.3 m and span of 65 4 m (Fig 1) Route 1 is themost important road in Japan, and 60 years after completion of the bridge, the daily traffic flow was 21 000vehicles, though bypass roads had been completedupstream and downstream of the bridgeAfter many years of use, such problems as crackedconcrete decks, corroded outer stringers, overstressedand deflected stringers, and scounng at the piers due tothe lowered river bed of the Fuji River have occurredAlso, as a result of the increased traffic flow, trafficcongestion caused by right turnmg cars holding thetraffic had become a big problemTo solve these problems, the substructure of the bridgewas reinforced, and the stringers and deck on four spansto the left bank were replaced. Moreover, two spans tothe right bank were replaced in Order to install a rightturnmg lane by the method that was chosen to completethe |ob with the least disturbance to trafficFor widening on the two spans to the right bank side,the roadway could not be widened by just adding stringers because the original bridge was a through trussBecause of this, it was deeided to replace the bridgewith the same type of truss (curved chord pratt truss)having wider floor beams. According to the replacementprocedure, a new bridge was erected along the existingbridge, and the deck work, pavement work and paintingwork were carried out for the new bridge. Then, thebridge was laterally transferred in place of the original

bridge while the traffic was stopped for a Short period Awalkway bridge alongside the bridge will be also laterallytransferred in the processThe superstructure replacement procedure is as follows(Fig 2)step 1. Make foundation for erection work.Assemble bent for assembly and lateraltransferAssemble new superstructure along side ofexisting bridgeConcrete deck is finishedstep 2. Two span of walkway bridge is transferredupstream to make room and replaced by temporary walkway bridgestep 3 Lateral transfer equipment are set in placeTwo span of new and old superstructures arelateral transferred separately upstream (Fig. 3).step 4 Disassemble existing superstructureDisassemble assembly bentstep 5. Lateral transfer walkway bridge to original Position.Disassemble lateral transfer bentThe special conditions of work are as follows:1) Since there was no bypass road, the method whichgave the least disturbance to traffic was adopted andthe extent of traffic stop was kept to a minimum2) Since the construction site was located in the FujiRiver, which is one of the three major rapids in Japan,

fll safety measures were taken against floods Workfor substructure and superstructure were performedduring the dry season (November to May) and thisshort allowable working time was a difficult conditionfor the superstructure workFortunately there were no ma|or floods, but fll countermeasures against floods were taken, and the work wascompleted safelyThe replacement work was performed by stopping theheavy traffic through Route 1 The work was safelycompleted without causing traffic congestions bymeans of PR activities performed in advance.

66.1*0 55C ssaisea

A ATflKKR^^tr+i 7f> Fig. 1 Elevation

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303_JJLj3i'-Mal#

flow -Q Hl^v

MS

flow F/p. 3 Lateral transfer

870

flow

flow rvXk* 3low 7f/ff. 2 Erection sequence

The replacement of the bridge after assembly, deck andpavement completed required the handling of a largeweight (830 tons/senes) But the lateral transfermethod was still capable of moving the superstructurewith the least period of traffic stop The lateral transferprocedure took 60 hours but a considerable time wastaken for setting and anchorage of bearings This wasdue to the time required for opening anchor holes andbearing mortar to harden With some modification andimprovements, it may be possible to reduce the timeThe lateral transfer itself took only a short time with theup-to-date equipment that was employed(Yoshio Matsuo)

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8. Strengthening of Bridge Slab at Kami-Imasu Bridge (Japan)

Japan Highway Public CorporationJapan Highway Public Corporation19641976

Owner:Engineer:Daete of Construction:Date of Repair:IntroductionThe maintenance of floor slabs of steel bridges has beena serious problem in Japan Highway Public Corporationsince the mid'60s. In 1974, the specifications for Highway Bridges of Japan Road Association were revised, sothat the thickness of slab should be increased by 4 to5 cm The floor slabs which were constructed accordingto the new specifications have scarcely been damagedHowever, the damage of the floor slabs of the bridgesconstructed before 1974 is still discovered and requiresrepair or strengthening As method of repair and strengthening, addition of stringers and steel plating haveoften been adopted The Kami-Imasu Bridge is an example where stringers were addedRepair WorkThe Kami-Imasu Bridge is a two-span continuous steelgirder, which was designed based on the 1966 specifications. The bridge length and width are 99 0 m and10 7 m. respectively. The slab is 16 cm thick andcovered by 7 5 cm thick asphalt concrete pavementAfter ten years of service, cracks in the slab increased tosuch an extent that it had to be repaired and strengthened. Finally it was deeided to install stringers inbetween the original main box girders and the originalcentral stringers as shown in Fig 1. The reasons for theadoption of this method are as follows1) The traffic volume was so large that it was difficult toconduet the repair work on the upper side of te slab.2) It was expected to be sufficiently effective ondecrease of the bending moment of the slab

07l(mm)

HiL(mm)

(Case-1)Loaded between -Jox Girder tid Added StringerBefore Repair

1 After Repair

P* 7 tot

(Case-2) Loaded on Added Stringer

(Case-})Loaded Jietween Central Stringer and Added StringerFig. 2 Effect of Repair

10,7 0 0 6 20fi20 Aspha11 Pavement t=75Concrete Slab t l60 Strengthening Girder n}?..;?:?'>:?:?:*I prftradi jfSS

:>: :' * WYIvIv I- ?X,>X,X,I vi..*.*.*V.V.VWAVA%VVtVVc.SVMfAV/AW71

IMSERIMEHTO HELLA MURATURAESIST HELLA PIASTRA DI RIPARTIZ.M ACCIAIO E SUCCESSIVO RtPKISTMODEL PARAMERTO

\- Poizetto SnultimeitoKU*fi'ff. 5 Cross section on bridge-pier

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11. Repair of the Todsburg bridge (Fed. Rep. of Germany)Owner:Year of construction:Repairs carried out in:Under the supervision of:Contractors:

Federal Republic of Germany19361371983Heidenheim MotorwayAuthorityWeidle and LudwigFischer

IntroductionThe Todsburg bridge (Fig 1) is located on the A8Autobahn between Stuttgart and Munich - one of thebusiest sections of motorway in Germany. It Standsbetween Stuttgart and Ulm at a point where the roadclimbs up into the Swabian Alb For structural reasons.the two roadway sections are completely separate fromeach other. Some 30 000 vehicles pass over the bridgein each direction every day. By the beginning of the1980's the concrete structure was in urgent need ofrepair - this Stretch of motorway now being over 50years old.

Description of the workThe concrete on the old arched bridges had sufferedextensive damage over the years. particularly fromdeicing salt This damage resulted - as is usually thecase - from failure of the conventional bridge waterproofing System, which was unable to cope with thesevere stress caused by traffic. temperature fluctuationsand structural movements over the years. It was therefore deeided that, in addition to the normal repair work, anew type of spray-on liquid Polyurethane would beapplied to form a waterproof membraneThe principal advantages of this new System are asfollows:- Seamless. homogeneous waterproofing produced in

one pass- High elasticity and elongation at break even at lowtemperatures- The waterproof membrane is bonded over the entiresurface of the Substrate, thus preventing any moisture Infiltration- Excellent crack-bndging effect- High water vapour permeability prevents any build-upof moisture beneath the membrane

1

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-

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