Dissertations / Theses on the topic 'Road infrastructure maintenance'

This thesis is a documentation of research on Geographical Information Technologies (GITs) as decision support tools in Road Infrastructure Maintenance (RIM) in Uganda. The main objective is to develop an operational framework within which the use of geo-information technologies can be enhanced as decision support tools in road infrastructure maintenance works of Uganda. Specifically, the research identifies the gaps and limitations in the use of and access to GITs for RIM and defines an algorithmic framework to accentuate the use of GITs in RIM. The research undertook a participatory multifaceted approach that included a review of documentation both in academia, in form of articles, journals, books, reports and research theses and also reports and documents prepared by the road infrastructure maintenance sector. Participant observations, field visits and measures, interviews and workshops were also triangularly employed to obtain the inherent answers. Content and GIS analyses were made to arrive at the findings that are documented in the papers which are part of the thesis. The gaps to using GITs in RIM have been found to include the lack of standardized datasets to address key nation-wide and local maintenance requirements, challenges on coordinating how geospatial data are acquired and utilized and the collection of duplicate data sets at the local and national levels. Also, the present institutional arrangements do not permit the formation of lasting partnerships and operating under a coordinated GIS infrastructure. The limitations to access of GITs in the sector include; the absence of policies for accessibility and standard use of GITs, lack of infrastructure to support utilization of geographic datasets, unavailability of and limited accessibility to geographic data, lack of geospatial capacity at individual and organizational levels and the digital divide. A nondeterministic algorithmic framework approach to the accentuation of GIT usage in RIM has been suggested. This framework involves strategies on; developing a policy on data collection guidelines emphasizing the use of GPS, satellite imagery and GIS, continuous undertaking of capacity building in the benefits of GIT use and the science involved, establishment of Local Spatial Data Infrastructures (LSDI) for road maintenance data and setting aside yearly budgets for the defined activities. In this framework, the dynamic segmentation data model is considered a superior data storage strategy for road maintenance data within the GIS. Dynamic Segmentation is the process of transforming linearly referenced data (also known as events) that have been stored in a table into features that can be displayed, queried and analyzed on the map through computations. It allows for the location of multiple events stored with linearly referenced attributes without any duplication with route geometry and in effect supports sharing of network infrastructure with different applications

The road authority is responsible for the construction and maintenance of the road network system. The authorities strive to reduce cost and time of maintenance activities and to control quality of work as well as keeping the road infrastructure in an efficient state using the traditional methods of contracting. Many road authorities have considered contracting out road maintenance to the private sector based on performance measures as an alternative and better solution than traditional methods of contracts. This method is named performance based maintenance contracting (PBMC). PBMC has received a significant attention from researchers and practitioners as it has a considerable success in minimizing infrastructure maintenance costs in many developed countries over the last two decades. The application of PBMC improves the road maintenance system by applying more efficient technologies and work methods. However, effectiveness of PBMC is still a challenge for developing countries because of resource and skill limitations, corruption, shortage of fund and poor management systems. Hence, the aim of this thesis is to analyse the potential and effectiveness of PBMC for road infrastructure maintenance systems of developing countries. This thesis presents a comprehensive state of the art review of the literature on PBMC that has been produced in recent years. This thesis defines and presents the benefits of PBMC. It briefly discusses the problems of traditional methods of contracting in developing countries. Application of PBMC in developing countries has been reviewed and analysed based on the published journal articles, conference papers, published reports and online databases.
Thesis (Masters)
Master of Philosophy (MPhil)
Griffith School of Engineering
Science, Environment, Engineering and Technology
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Thesis (MPA.) -- University of Limpopo, 2018
Road infrastructure is usually regarded as an economic backbone of the society. Local government has a responsibility to ensure that local roads are maintained in order to facilitate a movement of people, goods and services. The study was undertaken on the premise that local roads in Makhado Local Municipality are not promoting safety. That is, road infrastructure in this municipality is considered to be deteriorating. It is against this background that the researcher found it worthwhile to investigate critical challenges of maintaining road infrastructure in the Makhado Local Municipality focusing on the following towns, Makhado, Vuwani, Waterval and Dzanani only excluding unpaved communities and other small townships, namely Tshikota and Vleifontein. The objectives of the research were to determine the condition and effects of municipal road infrastructure within Makhado Local Municipality; to examine the legal framework governing the local municipality in the context of road infrastructure provision and maintenance as well as to recommend strategies to address challenges of road infrastructure within the municipality. The research employed both qualitative and qualitative in nature. A purposive research sampling approach was used to determine the inclusion of relevant respondents to the study. The research found out that the status of road infrastructure affect various people of different biographical background within the four towns of Makhado Local Municipality in a similar way. In the findings, the study highlight the fact that deteriorating roads conditions are often due to the following: a lack of professionals such as engineers to perform the necessary environmental scanning and identify problems in order to design the roads that suit the area, soil, landscape and climate and that other factors affecting the road infrastructure include corruption in procurement of road infrastructure projects; a lack of accountability of municipal officials; a lack or poor community involvement; and poor monitoring and maintenance of road projects. The study recommends that individuals with knowledge, expertise and skills be employed and further provide proper monitoring of the road projects.

The global infrastructure gap has continually widened over the last few decades. Industry reports and academic publications suggest that, in terms of road infrastructure, both advanced and developing economies have not paid sufficient attention to modernize their infrastructure assets. A wider road infrastructure gap signifies that highway conditions have declined because governments have not had enough resources for maintenance and rehabilitation. In the same way, it also indicates that congestion levels have grown and the level of service in most road networks has dropped because public agencies have not had sufficient funds to generate new highways and expand existing corridors. This dissertation, therefore, provided insights into the difficulties associated with improving the existing highway assets and the barriers related to expanding the current roadway capacity through public-private partnerships (PPPs). The research involved three interdependent studies. In the first study, I examined the continuous deterioration of the US highway system through a system dynamics model, which focused on the dynamics of capital investments and maintenance expenditures in the US road infrastructure. The results confirmed that the American highway system is currently stuck in a capability trap. This makes it difficult for the system to improve at the rates required by the country's economic growth. In my second investigation, my attention shifted toward the governance challenges related to building new roads and expanding highway capacity through PPPs. I developed a systems map of governance variables informed by past-published evidence from actual projects. By specifically examining the shaping phase of public-private initiatives, the work uncovered the effects of feedback relationships and interdependencies on PPP feasibility. This offered insights about the relationship between governance mechanisms and successful PPP development. In the third study, I utilized variables and relationships identified in my second investigation to develop a management flight simulator in order to better explain governance difficulties in the procurement phase of PPP projects. The simulator was implemented during an educational exercise with graduate students of civil engineering. By doing so, I confirmed that the simulator has the potential to increase our understanding of PPP procurement processes. Results indicated that the simulation tool was a suitable instrument to explain how government capacity, project uncertainty, and technical complexity influence PPP tendering. Overall, my findings across the three studies illustrate different means to understand why closing the global road infrastructure gap is challenging. Together, the three inquiries indicate that examining the road infrastructure sector as a socio-technical system contributes to improve our understanding of the expenditure dynamics related to existing assets and to enhance our comprehension of the governance challenges associated with developing new roads.
Ph. D.

This study set out to develop a framework within which the use of Geographical Information Technologies (GITs) can be enhanced in Road Infrastructure Maintenance (RIM) in Uganda. Specifically it was guided by 3 objectives; 1. To assess the gaps in the use of GITs for RIM in Uganda and the limitations to accessing these technologies, 2. To develop a methodological framework to enhance the use of GITs in RIM and 3. To develop a Geographical Information Systems for Transportation (GIS-T) data model based on the road maintenance data requirements. A participatory approach through a series of interviews, focus group discussions, workshop & conferences, document reviews, field observations & measurements and GIS analysis were employed. Based on the Spatial Data Infrastructure (SDI) concept and the principle of Causality, the gaps and limitations were established to mainly be concerned with data and organisational constraints as opposed to technical issues. They were classified to include; inadequate involvement of GITs in organisational activities, inappropriate institutional arrangements, absence of data sharing frameworks, budget constraints, insufficient geospatial capacity, digital divide in the perception, adoption & affordability of GITs among the stakeholders and the absence of a road maintenance Spatial Data Infrastructure (SDI). A methodological framework, comprising of 6 strategic components was developed to enhance the use of GITs in RIM. This included enactment of relevant policy components to guide GIT use, continuous capacity building, establishment of a road maintenance SDI, fostering collaboration and spatial data sharing frameworks, budgetary allocation based on defined activities inclusive of GIT initiatives, and adoption of a dynamic segmentation data model. Conceptual and logical data models were developed and proposed for the Sector. The conceptual model, presented using an entity relationship diagram, relates the road network to the point and line events occurring on it. The logical object relational model developed using the ESRI provided template represents the road and the point and line events in a total of 19 object classes. The Study concludes that in order to ground GIT benefits in the sector; technical, data and organisational concerns involved in GIT undertakings should be accorded equal emphasis. Institutionalisation and diffusion of GITs as aspects of the component strategies are regarded capacity building mechanisms earmarked to boost success in GIT initiatives. Further research on diffusion and funding models for GIT initiatives is recommended. It is suggested that aspects of the proposed model be considered when establishing GIT standards for the sector. The RIM sector is encouraged to embrace Science and Technology and to participate in Research and Development and particularly to adopt the culture of innovation considering the ready availability of off the shelf equipment, freeware and open source software that can foster informed decision making.

The Swedish road network is maintained by the Swedish Transport Administration, municipalities, and entrepreneurs with the goal of keeping the roads in satisfactory condition for traffic. The road operators are responsible for different roads and have several legislations that regulate construction and operation. One important aspect of winter road maintenance is the monitoring of the road situation ahead in order to call out resources for preventive measures. This study is performed at the company NIRA Dynamics with the purpose of going towards more digitized winter road information. The study explores different winter maintenance organizations in Sweden, investigates the importance of the information needed to be able to detect when roads are deemed too risky, and tries to gain an understanding of how the vehicle data provided by NIRA Dynamics best can provide a service for the winter road maintainers. This study is based on eight semi-structured interviews, user-tests aswell as a literature study. The findings of the study show that different winter maintenance organizations can differ a lot depending on the size and governing policies of the municipalities or entrepreneurs. The main differences can be found in their requirements and their method of monitoring the road situation ahead. The findings also show that the vehicle data is promising and has the potential to optimize and improve the overall winter maintenance planning. However, implementing and understanding the vehicle data in a real-world context requires collaboration from the different organizations to fulfill its value.

[Truncated abstract] The salinisation of agricultural land, urban infrastructure and natural habitat is a serious and increasing problem in southern Australia. Government funding has been allocated to the problem to attempt to reduce substantial costs associated with degradation of agricultural and non-agricultural assets. Nevertheless, Government funding has been small relative to the size of the problem and therefore expenditure needs to be carefully targeted to interventions that will achieve the greatest net benefits. For intervention to be justified, the level of salinity resulting from private landholder decisions must exceed the level that is optimal from the point of view of society as a whole, and the costs of government intervention must be less than the benefits gained by society. This study aims to identify situations when government intervention is justified to manage dryland salinity that threatens to affect road infrastructure (a public asset). A key gap in the environmental economics literature is research that considers dryland salinity as a pollution that has off-site impacts on public assets. This research developed two hydrological/economic models to achieve this objective. The first was a simple economic model representing external costs from dryland salinity. This model was used to identify those variables that have the biggest impact on the net-benefits possible from government intervention. The second model was a combined hydro/economic model that represents the external costs from dryland salinity on road infrastructure. The hydrological component of the model applied the method of metamodelling to simplify a complex, simulation model to equations that could be easily included in the economic model. The key variables that have the biggest impact on net-benefits of dryland salinity mitigation were the value of the off-site asset and the time lag before the onset of dryland salinity in the absence of intervention. ... In the case study of dryland salinity management in the Date Creek subcatchment of Western Australia, the economics of vegetation-based and engineering strategies were investigated for road infrastructure. In general, the engineering strategies were more economically beneficial than vegetation-based strategies. In the case-study catchment, the cost of dryland salinity affecting roads was low relative to the cost to agricultural land. Nevertheless, some additional change in land management to reduce impacts on roads (beyond the changes justified by agricultural land alone) was found to be optimal in some cases. Reinforcing the results from the simple model, a key factor influencing the economics of dryland salinity management was the urgency of the problem. If costs from dryland salinity were not expected to occur until 30 years or more, the optimal response in the short-term was to do nothing. Overall, the study highlights the need for governments to undertake comprehensive and case-specific analysis before committing resources to the management of dryland salinity affecting roads. There were many scenarios in the modelling analysis where the benefits of interventions would not be sufficient to justify action.

Road transportation is the most frequently used means of transporting goods and people in much of sub-Saharan Africa. Furthermore, because of the region's geographic nature, where many of the countries are landlocked, imports and exports of goods happen primarily by land and in this case by road transport. This is primarily due to the fact that other means of surface transportation like rail and navigable rivers are not well developed. Nonetheless, the lack of complementarity between the two land transportation modes, that is rail and road, has led to the over usage of the road. This has invariably led to congestion and deterioration of the road network with minimal investment in both the development and maintenance of the road infrastructure. Though there is an acknowledgement of this problem and attempts to address it through efforts like the Programme for Infrastructural Development in Africa (PIDA), and regionally in SADC thorough the adoption of the SADC Regional Infrastructure Development Master Plan Vision 2027 (RIDMP), much effort still needs to be put within individual countries to develop and maintain primary road networks that are able to connect to regional trade corridors.

La qualité et la fiabilité des infrastructures routières jouent un rôle majeur dans la sécurité routière. Cela est d'autant plus vrai lorsque qu'on s'intéresse à la circulation de véhicules autonomes qui doivent être capables à terme de circuler seuls dans l'environnement routier. Les récents travaux menés au sein de VEDECOM montrent qu'une signalisation horizontale routière claire et visible est importante dans sa prise de décision. La détection des lignes de marquage sont en grande partie réalisée par des caméras. Afin d'optimiser cette approche et prévenir les situations de non détection, cette thèse propose des outils d'analyse de fiabilité et d'aide à la maintenance de la signalisation horizontale. Aujourd’hui, la fiabilité des marquages est basée le phénomène de rétro-réflexion : un véhicule éclaire avec ses feux de croisement un marquage qui renvoie la lumière vers le conducteur. Pour établir son niveau de dégradation, des campagnes d'inspection sont réalisées par des rétro-réflectomètres montés sur des véhicules traceurs. La littérature des trente dernières années présente essentiellement des modèles de dégradation basés sur des méthodes de régression. Ces derniers présentent de nombreuses difficultés à être déployés dans le cadre d'un plan de maintenance. Cette thèse propose d'aborder ces questions sous l'angle de la théorie de la fiabilité et de la maintenance tout en tenant compte des pratiques actuelles. Une ligne de marquage est ici interprétée comme un système multi-composants monté en parallèle. Cette thèse propose de l'analyser en quatre points. Premièrement, l'ensemble des inspections est formalisé en une base de suivi. Si des données sont manquantes et si l'historique de maintenance est indisponible, alors différentes approches basées sur une Classification Ascendante Hiérarchique (CAH) sont proposées afin de les estimer. Deuxièmement, l'entretien de la totalité d'une ligne est logistiquement délicat. Une CAH de la base de suivi a pour fonction d'établir les marquages suivant un même modèle de dégradation. Les clusters sont géographiquement localisés et corrélés à des situations précises comme un échangeur ou une agglomération. Pour ces raisons, ils sont interprétés comme des zones de maintenance stratégiques. Troisièmement, réaliser une analyse de Weibull des marquages. Les rétro-réflectomètres n'indiquent pas précisément les instants de défaillance. Ils sont statistiquement censurés à gauche, à droite ou par intervalle. En alternative à la méthode du Maximum de Vraisemblance, une approche basée sur un algorithme EM est proposé afin d'établir le modèle de Weibull et les censures estimées les plus vraisemblables. Dernièrement, deux stratégies de maintenance sont proposées : systématique par rapport à l'âge et conditionnée par la dégradation courante. Elles sont en adéquation avec les pratiques de maintenance. La première permet une gestion passive de l'entretien tandis que la seconde permet une connaissance avancée de la ligne de marquage dans le temps. A partir d'un système multi-composants non réparable et fortement censuré, les composants suivant un même modèle de dégradation sont classables, chaque groupe connait un modèle de durée de vie et finalement il est possible de déduire un plan de maintenance adapté
The quality and reliability of road infrastructure and its equipment play a major role in road safety. This is especially true if we are interested in autonomous car traffic. Recent papers from VEDECOM Institut proves that a clear and reliable road marking is important in it decison making. Marking lanes are detected by camera. These markings need an accurate maintenance strategy to guarantee that the markings remain perceptible. This report proposes different solutions based on the reliabilty and maintenance theory. Today, the markings reliability is based on the retroreflective illuminance. A retroreflective marking reflects light from a vehicle headlight back in the direction of the driver. Marking retroreflectivity can be dynamically inspected using a retroreflectometer. The litterature of the last thirty years proposes degradation models for retroreflective marking based on a regression model. All of them have a common weakness: they are difficult to apply directly to a given road network. This report presents maintenance models who math with current maintenance actions. A marking lane is interpreted as multi-unit systeme. All unit are laid in parallel. The global maintenance strategy is based on four points. First, the whole inspection data is formalized into one monitoring base. If inspection data is missing or if the maintenance historic is unavailable else an estimation process based on the Agglomerative Hierarchical Clustering (AHC) is proposed. Second, to replace a whole markings lane is logistically difficult to work. Again, an AHC of the monitoring proposed several clusters. Each cluster presents it own degradation model. Clusters are geographically tracked and correlated to specific situation (interchange, urban area, bypass...). That's why a cluster is interpreted as a maintenance strategic area. Thirdly, a Weibull analysis of each cluster is done. Current retroreflectometers cannot detects the exact faillure moment. this information is statistically censored. Three cases are identified : left, right and interval censored. To parameter a Weibull model, an EM Algorithm is propoased as an alternative to the Maximum Likelihood Estimator. This algorithm is also an estimator to censored markings life time. Lastly, two classic preventive maintenance strategies are proposed : systematic according to the age and conditionned to the current degradation. Each one is credible according the current maintenance practice. The first prposed a passsive managament of the markings maintenance. The second ensures an advanced knowledge of the road network over the time. On a multi-unit system no-repairable and strongly censored, units which admit the same degradation model are identified by a clustering approach. Each cluster present it own Weibull analysis. Finally, an adapted maintenance strategy is done

Construction of infrastructure does not only mean large capital investments but also future costs to operate and maintain these assets. Decision making in planning and design of roads will impact the need of future operation and maintenance activities. Additionally, infrastructure management is often under increasing pressure of aging structures, limited budgets and increased demands from public which require transparency in the decision making. Life cycle costing is a methodology that takes into account costs throughout an asset’s life cycle including investment, operation, maintenance and disposal. Despite the methodology’s existence for more than 40 years, the practical application is often reported to be scarce in both private and public sectors. Implementation in road planning and management means a high complexity where the life cycle costing can to be applied from early planning, design, construction and management in which all influence life cycle cost. Life cycle costing can also be applied in many different ways, level of detail and for different type of studies. For effective implementation of life cycle costing in road planning, design and management, different considerations need to be understood. In this thesis the application of life cycle costing has been studied through case study research. The main case selected was an investment to convert a single carriageway road to a, so called, sparse collision-free road. Through widening and separation between driving directions the traffic safety is significantly improved. However, in recent years increased operation and maintenance costs have been associated with the road type. Especially concerns regarding increased road user cost during road works have been expressed. This case was examined in two case studies from different perspectives. The first one was to study the implications on project appraisal and the second one examined the possibility to optimise pavement design. Results from cost benefit analyses based on established road appraisal techniques indicated that operation and maintenance related costs had limited impact on profitability. The second study also indicated that future cost can be influenced differently depending on criteria for optimal alternative. Based on economic analyses using established techniques, increased operation and maintenance liabilities appear to be of limited concern, in contrary to the perception. In future research this need to be set in context of road management with refined analysis in order to study implications for future management.

QC 20141028

Urbanisation is increasing and more sustainable transport modes are promoted, in both the sustainable development goals and the national goals. Sweden has developed a national cycling strategy, with the purpose to improve cycling infrastructure and make more people chose the bike. While cycling is good for both environment, reduced congestion and personal health, the traffic mode comes with high risk of accidents. Insufficient operation and maintenance is one of the main causes of single accidents involving cyclists. To improve the road quality on existing paths, this study has in collaboration with NCC, developed a concept for reporting issues on paths for cyclists directly to the road manager. The aim is to increase the efficiency of inspections on cycling paths and to cover more risk related aspects. A pilot area was chosen, due to variations in contracts for NCC’s operational areas in Sweden. The choice of pilot area was Borås, based on type of contract, local initiatives and sufficient information available. The methodology of this project consisted of a general literature review, followed with a deeper study of contracts and seminars in Borås. The seminars provided local insight from the NCC workers and cyclists familiar in the area. A grading system for the reports was obtained through a multi-criteria analysis in which criteria was combined with weights based on risk factor to demonstrate the urgency from more sides than just the contact. An analysis of the strengths, weaknesses, opportunities and threats was made to evaluate the concept. The result is in the form of a reporting system where cyclists can register errands about problems on their cycling paths in a mobile application. An NCC administrator at the main local office will organise the reports into the relevant criterion and score it according to urgency. The errand is then graded based on the score combined with a weight for that criterion to represent the risk factor. Colour coded symbols will appear on a digital map, giving NCC a good overview of the cycling path that can help them prioritise and schedule maintenance more efficiently. It is expected that some of the reports will concern problems outside of NCC contract boarders, these will be handled separately in a Grey Zone. Either the errand will be forwarded to responsible road manager, or it will be used in action proposals to the contract holder. For this system to work, it is important that the users stay engaged. This is attained with a feedback mechanism allowing the user to follow the report throughout the process. It will be possible to receive notifications when the status of an errand is updated. During a seminar with local cyclists, personalised feedback was preferred. A suggestion to meet this request is given in the form of a gamification feature, where points and achievements illustrate the importance of the cyclist’s reports. To attract users, different incentives such as discounts or service might be necessary. A final recommendation from this project is to create a system with the intention to collaborate with local initiatives and stakeholders. The value of this concept lay in increased efficiency and quality of operation and maintenance of cycling path that will lead to a safer environment for the citizens.
Då befolkningsmängden i städerna ökar blir kravet på hållbarare transportmedel allt mer påtagligt. Sverige har utvecklat en nationell cykelstrategi med målet att öka cykelinfrastrukturen och få fler att välja cykeln. Att cykla har många fördelar, förutom att den är mer platseffektiv i trafiken och kan minska trafikstockningar, är den också bra för miljön och den personliga hälsan. En av de främsta nackdelarna är dock risken för olyckor, och bristande drift och underhåll av cykelvägarna är en av huvudorsakerna till singelolyckor med cyklister. För att förbättra vägkvalitén på de befintliga vägarna har den här studien, i samarbete med NCC, tagit fram ett koncept där cyklister kan rapportera in fel direkt till väghållaren. Målet är att effektivisera kontrollerna av cykelvägarna och integrera riskfaktorer i prioritering av arbetet. Borås valdes som pilotområde för denna studie då kontrakt för drift och underhåll varierar mellan olika områden. Valet av pilotområde baserades på lokala engagemang, medlemskap i Svenska Cykelstäder och kontraktsmodellen. NCC har ett regionalt kontrakt med Trafikverket för Boråsområdet vilket är fördelaktigt då dessa kontrakt är mer generella än lokala kontrakt. Arbetet började med en generell litteraturstudie i ämnet, efterföljt av en djupare studie av Boråskontraktet och seminarier för att fånga lokala förhållanden och önskemål. Utifrån detta utvecklades ett betygssystem med hjälp av en multikriterieanalys där kriterier från kontraktet vägs samman med en riskfaktor för att öka insikten hos väghållaren om vikten av ett problem på cykelvägen och göra det lättare att prioritera arbeten. Slutligen utfördes en analys av styrkor, svagheter, möjligheter och hot för att utvärdera konceptet. Ett konceptuellt rapporteringssystem där cyklister kan anmäla fel på cykelvägarna de använder dagligen via en mobil applikation är resultatet av denna studie. Ärendet hanteras via det lokala driftkontoret av en administratör som kategoriserar problemet och registrerar hur allvarligt det är. Via betygssystemet erhåller ärendet en prioriteringsordning och färgkodade symboler på en digital karta ger en bra överblick av cykelvägarnas kvalité som kan användas vid planering av underhållsarbetet. Det är också förväntat att detta system kommer ta emot rapporter som berör problem utanför NCC:s kontraktsramar, dessa hanteras i en så kallad Gråzon. Ärendena här kan antingen vidarebefordras till ansvarig väghållare eller användas för att skapa åtgärdsförslag till den aktuella kontraktshållaren. Det är viktigt att bibehålla cyklisternas intresse för rapporteringssystemet. Detta är tänkt att uppnås med hjälp av ett kontinuerligt återkopplingssystem där rapporterna kan följas genom hela hanteringsprocessen. Det ska också finnas en möjlighet för cyklisten att få notiser när ärendets status uppdaterats. Intresset för personlig återkoppling var stor, enligt deltagare i ett av seminarierna. Då det är tidskrävande för väghållaren att hantera ärenden på en personlig nivå föreslogs därför ett typ av personligt poängsystem med utmärkelser som ska illustrera vikten av rapporterna. Olika typer av belöningssystem i form av rabatterade erbjudanden eller cykelservice skulle ytterligare fånga cyklisters intresse för applikationen. En slutlig rekommendation är att skapa ett system i nära samarbete med de olika intressenterna. Värdet av det här konceptet ligger i den ökade effektiviteten och kvalitén av drift och underhåll på cykelvägar som leder till en säkrare miljö för medborgarna.

In countries with harsh winter climates extensive winter road maintenance is necessary to achieve traffic accessibility and road safety. These measures have high economic and environmental costs as snow free roads and winter road maintenance in Sweden today is achieved by a combination of mechanical snow clearance and the spreading of salt to prevent ice formation. The salt ends up in the roadside environment and has negative effects on groundwater and vegetation. An alternative to traditional winter road maintenance to obtain non-skid winter roads is the use of hydronic pavement(HP) systems. Existing HP systems in Sweden are powered by district heating which limits the application to urban locations. The goal is to utilize renewable energy sources such as geoenergy which can be used in both rural and urban locations. This thesis suggests Hamnbacken in Visby as a pilot project for a full-scale application of the proposed HP system using surface water source heat.The weather related road surface conditions on Hamnbacken, and the potential of a renewable energysource have been examined in this study and the proposed location has been found favourable for a HP system.
Länder med övervägande kallt vinterklimat är halkbekämpning en nödvändighet för trafikens framkomlighet och säkerhet. Åtgärderna som vidtas för att få snö- och isfria vägar är kostsamma samt har en hög miljöpåverkan, ett vedertagligt exempel är plogning och saltning. Saltet hamnar i slutändan inom vägens omgivande områden och har en negativ påverkan på grundvatten och vegetation. En alternativ lösning till traditionell halkbekämpning är uppvärmda vägar för att uppnå ett halkfritt vinterväglag. Befintliga väguppvärmningssystem i Sverige försörjs av fjärrvärme vilket är en begräsning då tillgången till fjärrvärme finns i anslutning till tätorter. Målet är att utnyttja förnybara energikällor såsom geoenergi som är tillgänglig både i tätorter och på landsbygden. Det här examensarbetet undersöker Hamnbacken i Visby som ett pilotprojekt för en fullskalig implementering av väguppvärmningssystem där sjövärme används som energikälla. Denna studie har undersökt väderrelaterade vägförhållanden på Hamnbacken samt potentialen för användning av sjövärme. Den föreslagna platsens förutsättningar har visat sig vara gynnsamma i detta avseende.

The aim of this thesis is to analyse how the road allotment system functioned as an institution to mobilise resources and organise the provision of roads. Through this institution every peasant was made responsible for certain parts of a road. The analysis focuses on road repair and maintenance in the Swedish region of Västmanlands län c. 1750–1850. Previous research has described the allotment system as unfair, unprofessional and ineffective in providing a functioning road system and has contrasted it against modern road management based on cash taxes or fees, a central administrative body and professional engineers and workers. The results indicate that the allotment system under certain circumstances helped minimise administrative expenses for mobilising resources and organising work. Through the allotment system local resources throughout the area could be exploited and there was no need to convert tax revenue into output. When roads had been divided into parts it was not necessary to continually plan and manage work efforts, and through the quality inspections punishment could easily be enforced and road standards guaranteed. The allotment model also enabled peasants to perform road work at a convenient time and to make long-term improvements in their road parts. This was only possible when there were no ambiguities concerning limits and occupants of every road section, and a high degree of societal continuity, which was enabled by tying the obligation to homesteads through a constant taxation index. Without these preconditions there was a risk that a section of the road was not maintained at all, making it necessary to redistribute road parts, which was a complicated, time-consuming, and costly process. This was due to difficulties in making small adjustments without influencing all road parts within a large area. Furthermore, an equal distribution of road sections was hard to accomplish since traffic and natural conditions varied, and every part was at a different distance from the gravel pit and from the peasants’ farms. The possibility to mobilise resources within the allotment system was also restricted in time and by the availability of maintenance materials.
Det svenska vägnätets uppbyggnad 1750-1944

O patrimônio de infraestrutura rodoviária brasileira através dos tempos está sobrevivendo com investimentos com grandeza de valor bem abaixo do que muitos outros países estão alocando. A questão de quanto investir em infraestrutura de transportes depende de múltiplas variáveis como a situação política e econômica do país, a característica da frota, sua dimensão territorial, sua matriz, os tipos de pavimentos utilizados e as condições climáticas. Portanto, estimar um valor a ser empregado em manutenção rodoviária de forma recomendável, deve ser resultado dos estudos que envolvam essas variáveis, como elas interagem entre si e como esse investimento retorna para a sociedade. Diante de tantas áreas precárias, administrar recursos para a infraestrutura de transportes é um desafio a ser ainda vencido no Brasil. É engajada nesse desafio, que essa dissertação é composta por três artigos que abordam os principais assuntos: (i) avaliação da gestão da manutenção rodoviária no Brasil, quanto a sua abrangência, investimentos e as experiências internacionais; (ii) os conceitos e etapas de um SGP (Sistema de Gerência de Pavimentos) e a sua importância no planejamento das intervenções de manutenção; (iii) aplicação prática com o software Highway Development and Management (HDM-4), avaliando os resultados econômicos com as variáveis International Roughness Index (IRI) e Volume Médio Diário (VDM) do tráfego iniciais de segmentos de uma rodovia federal, utilizando como alternativas de projeto programas usuais adotados pelos gestores da rodovia. A terceirização dos serviços de manutenção pelos departamentos rodoviários exige que tenham que planejar e administrar contratos de manutenção por pouco ou longo período. A aplicação prática do HDM-4 demonstra que, o planejamento, um componente de um SGP, deve ser considerado permanentemente pelos administradores públicos ou privados. A questão de quanto investir em manutenção nesse contexto depende de como se investiu em momento antecedente, tanto com os serviços de infraestrutura como nas etapas de inventário da malha, planejamento e elaboração de projetos. O sistema HDM-4 necessita de dados de entrada, tais como: características geométricas, mecânicas, dados históricos e de tráfego dos segmentos rodoviários; que devem ser preservados pelos gestores do sistema, de maneira que permita prever o desempenho do pavimento, os custos e benefícios para um período planejado. Durante a análise dos resultados de Valor Presente Líquido (VPL) com os IRI e VDM iniciais, verificouse que as maiores diferenças se encontravam nos segmentos com mesmo intervalo de IRI inicial mas com tráfego superior. As características da frota, seus custos operacionais bem como seus coeficientes de calibração devem ser considerados nas análises com o software HDM-4, visando uma boa gestão na manutenção rodoviária. Tendo em vista o fato do tráfego influenciar nos resultados e podendo alterar o planejamento da manutenção, se percebe como é importante o controle do gestor da rodovia nas cargas efetivas que estão sendo transportadas.
The patrimony of Brazilian highway infrastructure through the ages is surviving with investments of magnitude value well below of what many other countries are allocating. The question of how much to invest in transport infrastructure depends on multiple variables such as the political and economic situation of the country, the characteristic of the fleet, its territorial dimension, its matrix, the types of used pavements and weather conditions. Therefore, to estimate a value to be used in road maintenance of a recommended way should be the result of the studies involving these variables, how they interact and how this investment returns to society. In face of so many precarious areas, managing resources for transport infrastructure is a challenge yet to be overcome in Brazil. It is engaged in this challenge, that this thesis consists of three articles that discuss the main issues: (i) assess the management of road maintenance in Brazil, as its scope, investment and international experiences; (ii) the concepts and steps of a Pavement Management System (PMS) and its importance in the planning of maintenance operations; (iii) practical application with the software Highway Development and Management (HDM-4), evaluating the economic results with the variables International Roughness Index (IRI) and Annual Average Daily Traffic (AADT) of the initial traffic segments of a federal motorway, using as alternative project usual programs adopted by the highway managers. The outsourcing of the maintenance services by road departments requires that they have to plan and manage maintenance contracts for little or long period. The practical application of the HDM-4 shows that the planning, a component of the PMS should be considered permanently by public or private administrators. The question of how much to invest in maintenance in this context depends on how you invested in previous time, both with infrastructure services as with the inventory stages of the motorway network, planning and preparation of projects. The HDM-4 system requires input data, such as geometric and mechanical characteristics, historical data and traffic of road segments that should be preserved by system managers, in order to foresee the pavement performance, costs and benefits to a planned period. During the analysis of the results of Net Present Value (NPV) with the initial IRI and AADT, it was found that the greatest differences were in the same initial IRI segments range but with higher traffic. The fleet characteristics, their operating costs and their calibration coefficients should be considered in the analysis with the HDM-4 software, aiming at a good management in road maintenance. In view of the fact that traffic influences the results and can change the maintenance planning, one can perceive that the road manager control on actual loads being transported is important.

Gravel roads connect sparse populations and provide highways for agriculture and the transport of forest goods. Gravel roads are an economical choice where traffic volume is low. In Sweden, 21% of all public roads are state-owned gravel roads, covering over 20,200 km. In addition, there are some 74,000 km of gravel roads and 210,000 km of forest roads that are owned by the private sector. The Swedish Transport Administration (Trafikverket) rates the condition of gravel roads according to the severity of irregularities (e.g. corrugations and potholes), dust, loose gravel, and gravel cross-sections. This assessment is carried out during the summertime when roads are free of snow. One of the essential parameters for gravel road assessment is loose gravel. Loose gravel can cause a tire to slip, leading to a loss of driver control.  Assessment of gravel roads is carried out subjectively by taking images of road sections and adding some textual notes. A cost-effective, intelligent, and objective method for road assessment is lacking. Expensive methods, such as laser profiler trucks, are available and can offer road profiling with high accuracy. These methods are not applied to gravel roads, however, because of the need to maintain cost-efficiency.  In this thesis, we explored the idea that, in addition to machine vision, we could also use machine hearing to classify the condition of gravel roads in relation to loose gravel. Several suitable classical supervised learning and convolutional neural networks (CNN) were tested. When people drive on gravel roads, they can make sense of the road condition by listening to the gravel hitting the bottom of the car. The more we hear gravel hitting the bottom of the car, the more we can sense that there is a lot of loose gravel and, therefore, the road might be in a bad condition. Based on this idea, we hypothesized that machines could also undertake such a classification when trained with labeled sound data. Machines can identify gravel and non-gravel sounds. In this thesis, we used traditional machine learning algorithms, such as support vector machines (SVM), decision trees, and ensemble classification methods. We also explored CNN for classifying spectrograms of audio sounds and images in gravel roads. Both supervised learning and CNN were used, and results were compared for this study. In classical algorithms, when compared with other classifiers, ensemble bagged tree (EBT)-based classifiers performed best for classifying gravel and non-gravel sounds. EBT performance is also useful in reducing the misclassification of non-gravel sounds. The use of CNN also showed a 97.91% accuracy rate. Using CNN makes the classification process more intuitive because the network architecture takes responsibility for selecting the relevant training features. Furthermore, the classification results can be visualized on road maps, which can help road monitoring agencies assess road conditions and schedule maintenance activities for a particular road.

Due to unforeseen circumstances the seminar was postponed from May 7 to 28, as duly stated in the new posting page.

Winter road maintenance is a necessity during the winter in Sweden, since the weather reduce traffic safety and accessibility, which have great impact on people and society in general. Unlike the degradation process of paved road surface and subgrade, that develops slowly over several years, the general state of the winter road can change significantly within a couple of hours, thus demanding more of road maintenance organisations when it comes to planning and initiating maintenance actions. Today there is a wide range of available sensor technology, that can be utilized to monitor the condition of the winter road and provide decision makers with the required information to initiate maintenance activities at the right time. However, it is necessary for the user, e.g. maintenance staff and decision makers, to know how this type of technology can be applied to make the winter road maintenance more efficient. The aim of this thesis is to define the winter road maintenance process, what obstacles and problems are present and the information requirements that are associated with planning, initiating and performing the winter road maintenance activities. The thesis focuses on the maintenance process for municipalities in northern Sweden using the city of Kiruna as a case study. An interview study was performed at Tekniska Verken in Kiruna to collect empirical data, which forms the basis for the process- and flow charts that are presented in the result. Common failure modes, connected to the failures that usually leads to the initiation of a maintenance activity, are identified, based on the interviews and the quality declaration for winter road maintenance. The failure modes were connected to the workflows, to show the phases of the workflow where the information is useful. Based on this, suitable sensor technology is proposed, which partly or fully meet the identified information requirements, and monitors the interesting failure modes of each maintenance activity. The results show that the greatest need for information is found in the stage of assessment and decision-making regarding initiation of maintenance actions, especially when it comes to initiation of snow plowing and de-icing activities. Using vehicle-based sensor technology, the condition of the road can be continuously monitored, and the initiation of maintenance activities can be triggered when reaching a threshold. Having road weather information stations, e.g. monitoring air and road temperature, wind speed, precipitation and road condition, is also an important source of information for municipal winter road maintenance. The use of sensor technology results in maintenance processes with fewer activities and decision steps, and it generates more reliable data that simplifies the decision-making.
Vinterväghållning är en nödvändighet under vinterhalvåret i Sverige, då väderlek har en stor påverkan på trafiksäkerhet och framkomlighet för trafikanter. Till skillnad från nedbrytningen av belagd väg under barmarkssäsongen, som sker stegvis under flera år, kan vintervägens tillstånd försämras avsevärt inom bara ett par timmar. Detta ställer högre krav på vägunderhållsorganisationer vad gäller planering och initiering av underhållsåtgärder. Idag finns ett brett utbud av sensorteknik som kan användas för att övervaka vintervägens tillstånd, och förse beslutsfattare med nödvändig information för att kunna initiera underhållsaktiviteter vid rätt tidpunkt. Det är dock nödvändigt att användaren, dvs. underhållspersonal och beslutsfattare, har kunskap om hur denna teknik kan användas för att effektivisera vinterväghållningen. Syftet med arbetet är att ta reda på hur underhållsprocessen för kommunal vinterväghållning är utformad, vilka hinder och problem som förekommer samt vilket informationsbehov som finns i samband med planering, initiering och utförande av vinterväghållningsaktiviteter. Arbetet är avgränsat till att analysera vinterväghållningen i Kiruna kommun. En intervjustudie utfördes vid Tekniska Verken i Kiruna för insamling av empiriskt material, vilket utgjorde underlaget för de process- och flödeskartor som presenteras i resultatet. Med utgångspunkt ur intervjumaterialet och kommunens kvalitetsdeklaration för vinterväghållning, identifierades vanliga felmoder kopplade till de funktionsfel som leder till initiering av underhållsaktivitet. Felmoderna kopplades sedan till arbetsflödena, genom att visa i vilket skede i arbetet som information om dessa är användbar. Utifrån detta gavs förslag på lämplig sensorteknik som helt eller delvis kan tillgodose informationsbehovet som identifierats, samt övervaka de felmoder som är intressanta för respektive underhållsaktivitet. Resultatet av undersökningen visar att det är vid bedömning och beslut om initiering av underhållsåtgärd som informationsbehovet är störst, framför allt när det handlar om initiering av snöröjning och halkbekämpning. Genom att använda sensorteknik för kontinuerlig övervakning av vägens tillstånd, kan underhållsaktiviteter initieras vid definierade gränsvärden. Egna vägväderstationer som övervakar och mäter exempelvis luft- och vägtemperatur, vindstyrka, nederbördsmängd och typ samt väglag, kan vara till nytta för den kommunala vinterväghållningen oavsett vilken underhållsaktivitet det handlar om. Användningen av denna typ av teknik leder till effektiviserade underhållsprocesser med färre aktiviteter och beslutssteg, samt förenklad beslutsfattning baserat på mer tillförlitliga mätdata.

Performance goals for a highway system are an indication of the desired system condition, and the level of service to be provided to its users. Setting the appropriate performance goals has a significant impact on the way highway agencies conduct business. With growing needs and limited resources, the consequences of setting different levels of performance goals should be examined and compared to optimize the highway infrastructure needs at the network level. Three interacting sets of costs are typically considered for a complete economic appraisal of highway projects: construction, maintenance and road use costs. Due to the shift in focus from design-and-build mode to the repair-and-maintain mode, this study focuses on maintenance related costs and the road user cost aspects only. Maintenance and rehabilitation activities on pavement infrastructure are ongoing processes that are required for the entire road network. This suggests that for long planning horizons and geographically extensive networks, their application usually results in significant financial needs. Typically, highway agencies have based their policy decisions such as the target condition levels for the system on the budget needs for maintenance and rehabilitation actions. Since in most cases, the funding needs exceed the available budget, the required preventive and routine maintenance activities suffer or are overlooked completely. Failure to timely apply these maintenance actions cause the pavements to deteriorate more rapidly into condition states that require for more expensive rehabilitation actions during the life cycle of the pavement. Over time, a vicious cycle is instigated in which the maintenance and rehabilitation needs of the network keep increasing each year. Although most highway administrators acknowledge the fact that pavement preservation is perhaps the most effective way of using the limited budgets available, the costs associated with deferring maintenance actions is oftentimes overlooked when establishing performance goals for the system. Road user costs in the form of costs for vehicle operation have been recognized as another large component of the total transportation related costs. These costs are then arguably the most important to consider for a complete economic appraisal. Ironically, they are also often disregarded while making important policy decisions. Other road user costs such as those related to the impact of traffic congestion and detours caused by construction and maintenance activities are difficult to quantify and were not accounted for in this study. Although it is widely accepted that establishing suitable performance goal is critical for system maintenance and preservation, a framework that considers the inter-relationship between conflicting objectives of minimum maintenance and rehabilitation costs, deferred maintenance costs, and vehicle operating costs to the users does not exist. This thesis proposes a methodological framework that is aimed at assisting highway agencies with the problem of objectively analyzing policy decisions in terms of the performance goals for their highway networks that would minimize the total transport costs to the society. In a case study of the proposed framework, the highway network managed by the Texas Department of Transportation was examined for different performance goals. The results from the case study indicate that setting lower performance goals lead to savings in the M&R needs, but at the same time, they also significantly increase the exogenous costs such as deferred maintenance costs and the vehicle operating costs.
text

Submitted in fulfillment for the degree of Magister Technologiae: Engineering: Civil, Durban University of Technology, Durban, South Africa, 2013.
An increase in road traffic, poor road conditions and high numbers of road accidents are major challenges at the Port of Durban. Roads are considered as the most important transport mode at the Port of Durban. Road transport has taken almost 80% of the import and export cargo while railway transport is left with approximately 20%. It is estimated that 75 million lives in the world will be lost and 750 million people injured in road accidents in the first half of the 21th century. The Port of Durban is an important vehicle for facilitating economic growth of local, regional and national industries. For the Port to maintain global competitiveness with the current trend of globalization, it has to ensure that roads are well maintained, safe and have a smooth traffic flow with no delays. This study provides an overview of the road infrastructure within the Port of Durban in relation to road condition, safety, law enforcement and traffic. Existing and ongoing studies conducted in South Africa and abroad form part of the literature review. This study identifies factors that are affecting the condition of road infrastructure such as growth of container cargo, an increase in the dimension and weight of trucks, transport deregulation, port layout and handling equipments. Deregulation of road transport over the past years has resulted in an 80:20 split between road and rail transport putting more pressure on roads. Cost and time are the major deciding factors in the freight industry. Most customers prefer to use road transport due to the lower cost and reduced time compared to rail transport. There are eight major roads within the Port that connect the South, West and North of eThekwini Municipality namely Bayhead, Quayside, Maydon, Rick Turner, Wisely, South Coast, Bluff and Iran Roads. Asset verification and assessment of the condition of the existing eight major roads found that Quayside Road is in a better condition compared to the other roads. Maydon and South Coast Roads are low rated roads which are in a poor condition. Identification and assessment of the condition of 210 000m² of asphalt paved areas which included minor roads within the Port of Durban was also conducted. Most paved areas and roads fall under D (fair) category which is reasonable but maintenance work may be required within six months. Comparison between the condition of the eight major roads within the Port and outside the Port was investigated. The findings indicate that sections of roads outside the Port are in a better condition than sections within the Port. Traffic counts were conducted in order to determine the utilization of the existing eight major roads. Bayhead and South Coast Road are highly utilized roads. Road accident reports and death reports were analyzed on these roads. Most of the road accidents take place on South Coast Road. A questionnaire survey was conducted, targeting road users who travel on these roads within the Port. Feedback was obtained on the status of road conditions, safety and traffic within the Port of Durban. Findings of this survey revealed that most of the respondents don’t know where to report road defect/s within the Port. Approximately 37.5% of the road users felt not safe to drive on roads within the Port especially on South Coast Road. A high percentage of people (93%) witnessed accidents on these roads. Traffic signals within the Port are maintained by eThekwini Municipality and are very often non-functional. When road signs need to be repaired or replaced, it takes longer than expected. Also, there are limited parking areas around the Port resulting in trucks parking closer to the premises while waiting to collect or deliver cargo. This causes major traffic congestion, for example, on Maydon Road where most trucks park on the side of the road. Recommendations include assessment guidelines that could improve road condition, safety and traffic flow. Areas to be improved with regard to road infrastructure are also highlighted.
M

The study investigates the extent of distributional impacts of labour-intensive road projects using a geographical approach. The aim is to evaluate infrastructural effectiveness. The central premise is that the interface between road investment and economic development has broad implications that are beyond transportation’s basic purpose of providing access and mobility. Communities are motivated by the outcomes and impacts of road infrastructure development in improving the productiveness of the economy, in line with socio-economic development and other multiplying effects. The objective was to describe the nature and delivery mechanisms of labourintensive road projects, evaluate the impact thereof on the project participants and their communities and explore the constraints and challenges experienced by these initiatives. The impact of the Gundo Lashu programme was measured, based on an assessment of programme outputs, outcomes and impacts, to determine whether the project had the desired effects on individual participants and their households. A matched control case study design, using a combination of qualitative and quantitative approaches was adopted. The study found that the Gundo Lashu programme had achieved the expected outputs in terms of the total number of jobs created, total road length constructed and maintained. However, the communities’ socioeconomic outcomes and the impacts of the programme on poverty and sustainable livelihoods were mixed. These conclusions re-affirm the notion that the development of rural road infrastructure alone by labour-intensive construction methods, is not sufficient in tackling poverty. While government is focusing on addressing unemployment and skills development through labourintensive road construction programmes, there is a need to ensure proper integration of government services to make a significant impact. Huge deficiencies exist in the inter-linkages between the programme planning process and the municipal planning system and that there are a number of management and planning, structural and functional, human resources and funding barriers to proper planning, implementation and monitoring of projects within the Gundo Lashu programme. Various challenges and barriers emanates from lack of coordination, political interferences and lack of strategic direction. Key recommendations include comprehensive road planning, better project targeting mechanisms, development of guidelines for future maintenance, skills training and capacity development, and resultsbased monitoring.
Geography
D. Phil. (Geography)

Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia
As infraestruturas rodoviárias assumem uma importância fundamental no desenvolvimento económico de um país, sendo que as vias municipais em particular, são de grande relevância não só para as empresas, mas também para as pessoas que todos os dias as utilizam para os mais variados fins, numa lógica de mobilidade integrada.A manutenção destas infraestruturas tem sido um dos pontos fundamentais nas atribuições e responsabilidades das autarquias. Não há nenhuma autarquia que não tenha no seu Plano de Obras e respetivo Orçamento uma verba destinada à manutenção, reabilitação ou construção de infraestruturas de transportes.O desafio de construir um modelo de eficácia, eficiência e qualidade da intervenção, tem nos instrumentos financeiros ao dispor das autarquias, uma condição nem sempre fácil de ultrapassar. Para além das naturais dificuldades técnicas de inventariar a totalidade das patologias numa infraestrutura desta natureza, advém a dificuldade técnica de conceber, propor, caracterizar, efetuar o procedimento legal, adjudicar, contratar, realizar, fiscalizar, gerir, vistoriar, receber provisoriamente e finalmente rececionar definitivamente a intervenção numa infraestrutura rodoviária.Na dissertação de Mestrado num caso de estudo, é efetuada uma análise crítica dos procedimentos de concurso relativos a três intervenções de conservação de infraestruturas rodoviárias, com todos os elementos imprescindíveis, desde a deteção das patologias até à receção definitiva após a intervenção de conservação, contribuindo com a visão de quem tem que tomar a decisão de propor a contratação, como contratar, de acordo com o rigor da legislação vigente em Portugal. O outro estudo de caso, corresponde a uma intervenção relevante em termos municipais, com a implementação de um Plano de Investimentos na reabilitação da rede rodoviária municipal em quatro anos, o que poderá servir de modelo para outros municípios.As decisões tomadas harmonizarão uma melhor perceção e entendimento deste tipo de processos bem como as deliberações que devem ser realizadas, por todos os agentes envolvidos.
Road infrastructures have a fundamental role in the economic development of a country, and the municipal roads have a big importance not only for companies, but for the people that use them every day for various ends, in a integrate mobility approachThe maintenance of these infrastructures has been one of the fundamental points in the duties and responsibilities of municipalities. There isn’t any municipality that doesn’t have a budget for the maintenance, rehabilitation or construction of road infrastructures in their Works Plans and their respective Budget.The challenge of building a model of efficacy, efficiency and intervention quality, with the financial instruments available to the municipalities, isn’t always an easy condition to surpass. Apart from the usual technical difficulties of inventorying all the pathologies in a infrastructure of this kind, arise the technical difficulties of conceiving, proposing, characterizing, proceeding with the legal procedure, adjudicate, contracting, performing, supervising, managing, inspecting, receiving provisionally and finally definitively making a intervention in a road infrastructure. In the Master’s dissertation one case study will critically analyse the procedure for a contest relative to three interventions applied to a road infrastructure, with all the necessary elements, beginning at the detection of pathologies until the definitive reception after the maintenance intervention, contributing with the vision of who has to make the decision to hire, how to hire, according to the present legislation in Portugal. In the other case study corresponds to a relevant intervention in municipality terms, with the implementation of an Investment Plan in the rehabilitation of a municipal road in four years, that may become a model for others municipalities, executed by a public contest, with all its procedural stages. The decisions made will harmonize a better perception and understanding of this kind of procedures as well as the deliberations that must be made by all the agents involved.

This dissertation focuses on the development of data analytics approaches to two distinct important condition monitoring applications in civil infrastructure: structural health monitoring and road surface monitoring. In the first part, measured vibration responses of a major long-span bridge are used to identify its modal properties. Variations in natural frequencies over a daily cycle have been observed with measured data, which are probably due to environmental effects such as temperature and traffic. With a focus on understanding the relationships between natural frequencies and temperatures, a controlled simulation-based study is conducted with the use of a full-scale finite element (FE) model and four regression models. In addition to the temperature effect study, the identified modal properties and the FE model are used to explore both deterministic and probabilistic model updating approaches. In the deterministic approach (sensitivity-based model updating), the regularization technique is applied to deal with a trade-off between natural frequency and mode shape agreements. Specific nonlinear constraints on mode shape agreements are suggested here. Their capabilities to adjust mode shape agreements are validated with the FE model. To the best of the author's knowledge, the sensitivity-based clustering technique, which enables one to determine efficient updating parameters based on a sensitivity analysis, has not previously been applied to any civil structure. Therefore, this technique is adapted and applied to a full-scale bridge model for the first time to highlight its capability and robustness to select physically meaningful updating parameters based on the sensitivity of natural frequencies with respect to both mass and stiffness-related physical parameters. Efficient and physically meaningful updating parameters are determined by the sensitivity-based clustering technique, resulting in an updated model that has a better agreement with measured data sets. When it comes to the probabilistic approach, the application of Bayesian model updating to large-scale civil structures based on real data is very rare and challenging due to the high level of uncertainties associated with the complexity of a large-scale model and variations in natural frequencies and mode shapes identified from real measured data. In this dissertation, the full-scale FE model is updated via the Bayesian model updating framework in an effort to explore the applicability of Bayesian model updating to a more complex and realistic problem. Uncertainties of updating parameters, uncertainty reductions due to information provided by data sets, and uncertainty propagations to modal properties of the FE model are estimated based on generated posterior samples. In the second part of this dissertation, a new innovative framework is developed to collect pavement distress data via multiple vehicles. Vehicle vibration responses are used to detect isolated pavement distress and rough road surfaces. GPS positioning data are used to localize identified road conditions. A real-time local data logging algorithm is developed to increase the efficiency of data logging in each vehicle client. Supervised machine learning algorithms are implemented to classify measured dynamic responses into three categories. Since data are collected from multiple vehicles, the trajectory clustering algorithm is introduced to integrate various trajectories to provide a compact format of information about road surface conditions. The suggested framework is tested and evaluated in real road networks.