This thesis is concerned about the development of computer data base management system for the assessment of masonry bridges. The various techniques of assessment and remedial measures of masonry bridges are outlined, their shortcomings described. A justification for an alternative method of assessment is given. A review of computer data base management systems is carried out. The reasons for adopting data base management systems is given as well as the reasons for choosing a particular type of data base management system. The common faults associated with masonry structures are described and the problems of identifying these faults are described. The part played by the individual components of a masonry arch bridge is given and the significance of faults on the individual components of the structure is described. A detailed description of the type, in general of the data base system chosen is given followed by a detailed description of a special case of the type chosen, which is the system that was used for the project. A description of how the system was developed is given followed by the way the system operates. A detailed description of how the system can be used is then put forward and the problems associated with the development of the system are outlined. Finally, a description of the implications of the system to the practising engineer is given.

The trend in many countries is to outsource maintenance with competitive tendering. The design of the tender is then a crucial issue. A new type of tendering contract, called "Integrated Bridge Maintenance", was introduced in one experimental area in Sweden. In this case the preventive bridge maintenance is separated from the standard road maintenance contract. The ideas behind these changes are that the new approach can increase efficiency through a combination of in­creased specialization, economies of scale and through giving the private contractor a greater degree of freedom concerning exactly what to do and exactly when to do it. A pilot project has been running since 2004 for all bridges in Uppsala County with about 400 bridges and since 2007 for all bridges in Örebro County with about 700 bridges.   The experiences and lessons from this pilot project are presented in this thesis together with guidelines on how to procure Integrated Bridge Maintenance in the future. An important feature of the contract was that it contained a combination of specific measures that the contractor should carry out and properties of the bridges that the contractor was responsible to maintain. This created a balance between predictability and flexibility for the contractor. The contractor could make long term planning for the work. The client was satisfied because of increased com­petence and a low price. The latter can partly be explained by the possibility for the specialised bridge crew to receive additional work from other clients. As information about old bridges always is incomplete a partnering structure needs to be built into the contract. Experi­ence has also shown that a conscious policy to maintain long run competition is important. The general conclusion is that the project was seen as successful and as creating more "value for money".   To manage a bridge stock optimally from a life cycle perspective is a very complex task, since the condi­tions for the individual bridge can vary greatly from place to place which the answers from the research questions indicate. Besides following-up and evaluating the Integrated Bridge Maintenance projects a number of research questions have been studied.   Is Integrated Bridge Maintenance a successful method to increase the effectiveness and to increase the standard in bridge maintenance alternatively increasing the service life for the bridge stock at an optimal cost, i.e., will IBM lead to lower LCC? It is difficult to answer this question with exact numbers after so short time, but so far the opinion is that the effectiveness has increased. How can a bridge stock develop over a long time e.g. 15 years? Based on historical data one can calculate, for instance, new construction rate, demolition rate and average age for the bridge stock. This information could together with different future scenarios be a basis for different bridge management strategies for the actual bridge stock. What is the real service life for a bridge? Survival analysis for the different types of bridges in the actual bridge stock will give a good estimate of the different expected service life. Why and at which age are bridges de­molished? Two main reasons were found in this study: deterioration process of the bridge had gone too far and/or load bearing capacity was too low, and road were rerouted. What is the real service life for a bridge edge beam, one of the most often repaired element of Swedish bridges? Survival analysis of edge beams located on different types of roads will give a good estimate of the different expected service life.   How should a long-term contract for bridge maintenance and specially Integrated Bridge Maintenance be procured? The bridge manager should have a good understanding of the answers on the research ques­tions above when the tender documents are to be prepared for the actual bridge stock. Thereafter the area that the contract should cover could be chosen, a good balance between properties and measures, defining the working cycle for properties, a flexible partnering structure in the contract and a suitable length of the contract (x years) inclusive an option (+ y years) and finally good incentives in the contract.   To sum up, the main purpose with the doctoral project has been reached. A model for procurement of bridge maintenance has been developed; see the projects in Uppsala and Örebro. The contractor has deve­loped more effective methods for bridge maintenance. The doctoral project has been a step closer to the end goal of reducing the society’s costs for bridge maintenance in the future. The bridges should be func­tional to the lowest possible cost during its expected service life (LCC). The doctoral project has also con­tributed with new knowledge in the area of bridge maintenance, the actual development of a bridge stock over time, real service life for road bridges in Sweden and survival analysis. / QC 20100826

In Sweden, as in many other countries, preventive maintenance of structures andbridges is considered important. It provides several benefits such as prolonged lifespan or service life, less need for repair, and hopefully reduced costs and lowerenvironmental impact. A large part of Sweden’s bridge stock is getting quite old. The idea that small actionscan improve and/or prolong the status of the bridge and postpone needs for repairor prevent damage with a reduction in life cycle cost is generally in the owner’sinterest. One such preventive maintenance measure is the annual washing ofbridges. While clear positive effects have been observed on the expansion joints,drainage system, and the bridge’s visual appearance, an important question is howthe washing affects chloride ingress, mainly from de-icing salts, in reinforcedconcrete bridge members. The hypothesis is that the high-pressure washing cleansaway the contaminants on the surface and in the long run reduces the chloridecontent. While the practical experience has been positive in Sweden, no research hasyet been done concerning the effect of high-pressure washing on chloride ingress inconcrete bridges. A study has been conducted on the preventive bridge maintenance practice of theSwedish Transport Administration (STA) and Swedish municipalities. This work hasbeen based on a literature review, a survey of municipalities’ bridge maintenance,and practical participation with contractors during annual maintenance. Field andlaboratory tests were carried out on the effect of washing on chloride ingress in twotypes of concrete. A field station was installed on an edge beam of a bridge and wasfollowed over three years’ exposure including winter seasons, winter maintenance,and annual washing in June. Also, an accelerated test method was developed in thelaboratory to simulate the yearly exposure and test the effect of high- pressurewashing in a long-term simulation over just a few weeks. The practical aspects of bridge maintenance seem to be quite similar betweenSweden and in other countries. However, in terms of descriptions of and availablemeans for maintenance and repairs, there seem to be larger differences. For the fieldstation, the results after one year’s exposure do not show anything more than theanticipated difference in chloride ingress between the two concrete types understudy. For year two, a slight difference indicated that washed samples had a reducedchloride content. For year three, however, there was no distinct difference betweenivwashed and unwashed samples. The reasons for this need to be further investigatedand examined. This will be done in the continuous tests of field exposure. The laboratory test method has been developed and successively improved. The shape and levels of chloride ingress are reasonable and comparable with fieldsamples. However, there is a need to examine the effect of natural rain exposurewhich might have the same or greater effect of diluting the chloride content aswashing the surface once a year. Other factors also need to be considered, such aswhen and how often the maintenance is performed. A first step to be able to examinethis has been completed through the development of the accelerated test method. / I Sverige, som i många andra länder, anses förebyggande underhåll avkonstruktioner och broar vara viktigt. Det har flera fördelar, som att förlängalivslängden eller bruksskedet, minska behovet av reparationer och förhoppningsvisminska kostnader och miljöpåverkan. En stor del av Sveriges brobestånd börjar bli relativt gammalt. Det gör attförebyggande underhåll får mer uppmärksamhet och ges större vikt. Idén att mindreåtgärder kan förbättra och/eller förlänga standarden på bron och förskjuta behovetav reparationer eller förebygga skador med en minskning i livscykelkostnader ärgenerellt i ägarens intresse. En typ av förebyggande underhåll är den årligatvättningen av broar. Tydliga positiva effekter kan ses på fogar, dränering samt bronsvisuella intryck men en viktig fråga är hur tvättningen påverkar kloridinträngning från huvudsakligen tösalter i armerad betong. Hypotesen är att högtryckstvätt tarbort föroreningar på ytan, vilket på lång sikt minskar kloridmängden i betongen. Den praktiska erfarenheten ska ha varit positiv i Sverige, men ingen forskning har utförtspå vilken effekt högtryckstvättning har på kloridinträngningen i en bro av betong. En studie om det förebyggande brounderhållet hos Trafikverket och kommuner harutförts med hjälp av Trafikverkets och föregångarna Vägverkets dokument, annanlitteratur, en enkät till kommuner samt medverkan och observationer av detpraktiska vid utförandeentreprenaders årliga utförande av underhållet. Fält- ochlaboratorieprover för undersökning av tvättningens effekt på kloridinträngningenhar utförts. En fältstation på en kantbalk på en bro har installerats och följts undertre års exponering, med vinterklimat, vinterunderhåll samt årlig tvättning i juni. Enaccelererad provningsmetod har utvecklats för att simulera den årliga exponeringenoch undersöka effekterna av högtryckstvättning i en långtidssimulering på baranågra veckor. Ur praktisk synvinkel verkar brounderhåll vara ganska likt i Sverige och andraländer. Dock verkar beskrivningar och tillgängliga ekonomiska medel för underhålloch reparation visa större skillnader, vilket kan ha en stor påverkan på broarnasskadestatus. För fältstationen, är resultatet efter ett års exponering inte speciellttydligt förutom den förväntade skillnaden mellan de två undersökta betongtyperna(en äldre och en modern, mer beständig kvalitet). För år två syns en mindre skillnadmellan tvättade och otvättade prover. Skillnaden kan inte observeras i resultaten förår tre dock. Orsaken till detta måste undersökas vidare. Detta görs genom dekontinuerliga provningarna som fortsätter. Den accelererade provningsmetoden har utvecklats och kontinuerligt förbättrats.Formen och nivån på kloridinträngningen kan anses rimliga och jämförbara (påformen) med fältprover. Dock finns det ett behov av att undersöka påverkan avnaturligt regn vilket kanske har samma eller större effekt på att späda utkloridmängden som att högtryckstvätta ytorna en gång per år. Andra aspekterbehöver också undersökas, till exempel när och hur ofta underhållet ska utföras. Ettförsta steg att möjliggöra det har avslutats med utvecklingen av den accelereradeprovningsmetoden. / <p>QC 20220509</p> / Förebyggande Brounderhåll

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23483号 / 工博第4895号 / 新制||工||1765(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 杉浦 邦征, 教授 清野 純史, 教授 八木 知己 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

<p dir="ltr">Girder ends of steel bridges can be corrosion damaged due to deicing salts, water, and other contaminants leaking from deck expansion joints. When the corrosion becomes significant, it can decrease the sectional properties of end steel girders and eventually reduce structural resistance against bearing and shear. Conventional methods that are typically used to repair corrosion-damaged girders require a substantial amount of time and resources to complete and often cause public inconvenience due to traffic lane closure. Therefore, there is a need for practical, rapid, and robust repair methods that can be implemented by maintenance personnel of a local Department of Transportation (DOT).</p><p dir="ltr">In this study, five innovative repair methods for corroded steel girders were evaluated through a selection process called the House of Quality Matrix, a commonly used tool in the consumer product industry. After completing the evaluation and additional numerical simulations, the "Sandwich Panel" repair method was selected for further investigation. The main concept of the proposed "Sandwich Panel" repair method is the encasement of the corroded region with a filler material reinforced by threaded rods. Two thin steel plates installed on both girder sides serve as stay-in-place formwork, expediting the installation process. This repair method eliminates labor-intensive steps of jacking, welding, and formwork disassembly, making it more cost-effective and less time-consuming.</p><p dir="ltr">The structural performance of the method was evaluated experimentally by conducting seven large-scale tests. Various test parameters were considered in the tests, including i) threaded rod layout, ii) filler material, and iii) support condition. The test specimens were corrosion-damaged steel girders from decommissioned highway bridges in Indiana. The experimental results indicate that the method is effective enough to recover the girder's original design strength. The experimental evaluation was followed by a numerical parametric study using finite element models benchmarked using the experimental results. Detailed design guidelines and recommendations were developed based on the experimental and numerical results.</p>

Trafikverket ansvarar för det statliga vägnätet i Sverige. Vägnätet består av cirka 15 500 broar som ständigt utsätts för olika former av nedbrytning. Broarna behöver därför underhållas med jämna mellanrum både för att hålla broarna i ett bra skick och för att motverka att nedbrytningen påskyndas. Under de senare åren har Trafikverket utformat en ny upphandlingsmetod av brounderhåll. Den går ut på att allt brounderhåll för en region paketeras, i ett s.k. brounderhållspaket, som en entreprenör sköter i en femårig period. I brounderhållspaketen ingår förebyggande underhåll, avhjälpande underhåll och akut underhåll. Syftet med det här arbetet är att följa upp den nya formen att upphandla brounderhåll i paket. Målet är att tydliggöra vilka vinster, eller förluster, som gjorts i effektivitet i hela kedjan sedan införandet av brounderhåll i paket.   De metoder som använts vid skapandet av examensarbetet är litteraturstudier, möten och intervjuer samt analyser, beräkningar och jämförelser. Resultatet visar hur beställare, entreprenör och konsult arbetar i brounderhållspaket och vad som har förändrats jämfört med hur de arbetade med brounderhåll tidigare. De största effektivitetsvinsterna är administrativa. Genom att brounderhållspaketen är en totalentreprenad läggs mycket av ansvaret över från beställaren till entreprenören och därmed får beställaren tid till andra arbetsuppgifter. Eftersom brounderhållet numera ligger i eget kontrakt som löper under en längre tid får beställaren också en kunnig entreprenör till arbetet vilket minskar antalet grundläggande frågor och frigör tid. Entreprenören får mer frihet när arbetena skall utföras och samtidigt mer tid till att planera underhållsarbetet. Genom en tät kommunikation mellan beställare och entreprenör blir beslutsvägarna kortare vilket effektiviserar hela kedjan. Skaraborgspaketet var ett av de första brounderhållspaketen och det skiljer sig mycket från de senare underhållspaketen. Den största förändringen ligger i förfrågningsunderlagen. Skaraborgspaketet utgick från en fiktiv bro medan förfrågningsunderlagen i de nyare paketen behandlar verkliga åtgärder som entreprenören kommer att utföra under den kontrakterade tiden. / Trafikverket is responsible for the public traffic network in Sweden. The traffic network contains around 15 500 bridges that constantly are exposed of different kinds of degradation. The bridges must therefore be maintained at regular intervals both to keep bridges in good condition and to prevent the degradation accelerated. During the last years Trafikverket has developed a new procurement method of bridge maintenance. The method involves that all bridges maintenance of a region is being bundled to one contract that an entrepreneur handles for five years, a socalled bridge maintenance package. A bridge maintenance package exists of preventive maintenance, remedial maintenance and emergency maintenance. The purpose of this paper is to follow up the new form to procure bridge maintenance in package. The goal is to clarify the gains or losses made in efficiency since the introduction of bridge maintenance in package. Methods used in the creating of this thesis are literary studies, meetings and interviews along with analysis, calculations and comparisons. The result lays the foundation for the client, contractor and consultant working in the bridge maintenance package and further what has changed from the way they were working on bridge maintenance earlier. The largest efficiency gains are administrative. Because a bridge maintenance package is a turnkey contract the majority of responsibility is put on the contractor, instead of the client, which gives the client time for other tasks. Nowadays the bridge maintenance is in a separate contract which lasts for a longer time which gives the client a more qualified contractor for that kind of work which is reducing the number of fundamental questions and gives the client extra time. The contractor will get more operating freedom and at the same time more time to plan maintenance work. Through frequent communication between client and contractor decision-making paths becomes shorter which gives more efficiency throughout the entire process. The package in the region Skaraborg was one of the first bridge maintenance packages and it differs a lot from later maintenance packages. The biggest difference is in the contract documents. The package in Skaraborg was based on a fictional bridge while the more recent maintenance packages documents addresses the real action which the contractor will perform during the contracted period.

Sverige har som många länder runt om i världen en åldrande infrastruktur och behovet av underhåll stiger. I en artikel i Svenska Dagbladet från 21/9–2018 redovisar analys- och teknikkonsultföretaget WSP en grov uppskattning att 300 miljarder kronor behöver investeras för att rusta upp existerande infrastruktur. Efter upprustningen skulle det krävas ca 25 miljarder kronor årligen för att utföra löpande tillståndsbedömning och underhåll av Sveriges väg- och järnvägsnät. Idag används inspektioner för att bedöma broars tillstånd. Det finns tre olika inspektionstyper; huvudinspektion, allmäninspektion och särskild inspektion. Structural Health Monitoring (SHM) är en teknik som globalt används mer och mer som en metod vid tillståndsbedömning av broar. SHM siktar mot att i realtid utföra automatisk bedömning av hela konstruktionens och de enskilda skadornas tillstånd. SHM använder sig av sensorer placerade på kritiska positioner för att samla in mätdata som jämförs med i förtid definierade gränsvärden. I Sverige används SHM sparsamt idag där kunskapen ligger på akademisk nivå och det råder en osäkerhet om hur SHM ska implementeras i praktiken. Genom att implementera SHM, kan skador upptäckas i ett tidigt skede och minimeras genom att snabbt utföra reparationer på konstruktionen innan skadorna blivit kritiska. Studien syftar till att producera en rapport som kan användas som en guide för hur SHM kan implementeras samt visa på hur SHM-systemen har implementerats på tidigare projekt. Rapporten skall ge läsaren en helhetsbild över hur tillståndsbedömning går till idag, vilka skador som är vanligt förekommande samt hur SHM kan användas som ett verktyg vid tillståndsbedömning. Rapporten syftar också till att ge en övergripande förklaring på svenska av SHM-tekniken och vad som behövs för implementering. Öppna ostrukturerade intervjuer genomfördes med forskare inom SHM och skador på betongkonstruktioner samt sakkunniga inom tillståndsbedömning. Intervjuerna användes som utgångspunkt för vidare studier av vanligt förekommande skador och SHM-tekniker. I litteraturstudien användes olika vetenskapliga databaser såsom Diva och ScienceDirect, samt KTH:s bibliotek för att få fram tidigare material om betongskador på broar, deras skademekanismer och om SHM-tekniken. Vidare hämtades information från ett antal doktorsavhandlingar, artiklar och tidigare examensarbeten. Genom litteraturstudie och intervjuer med sakkunniga kom studien fram till att armeringskorrosion och sprickor i betongen är skador som är vanligt förekommande i betongbroar. Skadornas skademekanismer beskrivs i rapporten. Studien identifierade tre olika system som kan användas för detektering och övervakning av armeringskorrosion och sprickor, de systemen är akustisk emission, SOFO-system (SOFO är en förkortning för Surveillance d'Ouvrage par Fibers Optics) och MuST-system (MuST är ett kommersiellt namn). Rapporten ger exempel på hur systemen kan användas för detektering och övervakning av skadorna genom att presentera fyra fallstudier där systemen har använts. Två av fallstudierna presenterar hur akustisk emission har implementeras och två av fallstudierna presenterar hur SOFO-systemet har implementerats. Studien kunde inte identifiera någon fallstudie för MuST-systemet och hur systemet har implementerats. Slutsatsen av studien är att SHM kan användas som ett komplement vid tillståndsbedömningar men man kan inte utföra automatiserade tillståndsbedömningar idag. / Like many countries around the world, Sweden has an aging infrastructure and the need for maintenance is increasing. In an article in Svenska Dagbladet from 21 / 9–2018, the analysis and engineering consulting company WSP reports a rough estimate that SEK 300 billion needs to be invested to upgrade existing infrastructure. After the upgrade, it would require approximately SEK 25 billion annually to carry out ongoing condition assessment and maintenance of Sweden's road and railway networks. Today, inspections are used to assess the condition of bridges. There are three types of inspection; main inspection, general inspection and special inspection. Structural Health Monitoring (SHM) is a technology that is globally more used as a method for condition assessment of bridges. SHM aims to perform automatic assessment of the state of the entire construction and individual damages in real time. SHM uses sensors placed at critical positions to collect measurement data compared to pre-defined limit values. In Sweden, SHM is used sparingly today, where knowledge is at an academic level and there is uncertainty about how SHM should be implemented in practice. By implementing SHM, damage can be detected at an early stage and minimized by quickly performing repairs on the design before the damage becomes critical. The study aims to produce a report that can be used as a guide on how SHM can be implemented and show how the SHM systems have been implemented on previous projects. The report should give the reader an overall picture of how condition assessment is performed today, which damages are common and how SHM can be used as a tool when assessing the condition. The report also aims to provide an overall explanation in Swedish of the SHM technology and what is needed for implementation. Open unstructured interviews were conducted with researchers within SHM and damages to concrete structures as well as experts in condition assessment. The interviews were used as a starting point for further studies of commonly occurring damages and SHM techniques. In the literature study, various scientific databases were used, such as Diva and ScienceDirect, as well as KTH's library to obtain earlier material on concrete damage to bridges, its damage mechanisms and about SHM technology. Furthermore, information was obtained from a number of doctoral dissertations, articles and previous degree projects. Through literature study and interviews with experts, the study concluded that reinforcement corrosion and cracks in the concrete are damages that are commonly found in concrete bridges. The damage mechanisms are described in the report. The study identified three different systems that can be used for detection and monitoring of reinforcement corrosion and cracks, those systems are acoustic emission, SOFO system (SOFO is an abbreviation for Surveillance d'Ouvrage pair of Fiber's Optics) and MuST system (MuST is a commercial name). The report gives examples of how the systems can be used for the detection and monitoring of the damages by presenting four case studies where the systems have been used. Two of the case studies present how acoustic emission has been implemented and two of the case studies present how the SOFO-system has been implemented. The study could not identify any case study for the MuST-system and how the system was implemented. The conclusion of the study is that SHM can be used as a supplement to condition assessments but cannot for the time being used for performing automated condition assessments today.