Bridge edge beams in Sweden may involve up to 60% of the life-cyclemeasure costs incurred along the road bridge’s life span. Moreover, usercosts as means of traffic disturbances are caused. Consequently, the SwedishTransport Administration started a project to find better alternativeedge beam design proposals for the society.The goal of this thesis is to contribute to the development of bridgeedge beam solutions that can result better for the society in terms of totalcost and still fulfill the functional requirements, through the evaluation ofnew concepts. A life-cycle cost analysis was carried out to assess the proposedalternatives. The results served as a guidance to identify alternativesthat could qualify for more detailed studies. One such proposal wasa solution without edge beam. Since the edge beam is known to distributeconcentrated loads, the removal of such member could lead to loss ofrobustness of concrete bridge deck slabs. Thus, a structural analysis todetermine the influence of the edge beam was performed through nonlinearfinite-element modelling validated from experimental evidenceavailable in the literature. An assessment of the existing calculationmethods for the overhang slab is also presented.The results show that the edge beam behaves as a load-carrying memberwhich contributes to a wider distribution of shear forces. An increasedload resisting capacity for reinforced concrete bridge deck overhang slabswas documented. The removal of the edge beam would imply loss of robustnessin the bridge, which might have to be counteracted by an increaseof the thickness of the deck slab. / <p>QC 20160205</p>

Climate change is expected to lead to more frequent extreme precipitation events, floods and changes in frost/thawing cycles. The frequency of road closures and other incidents such as flooding, landslides and roads being washed away will probably increase. Stronger demands will be placed on the function of road drainage systems. The overall aim of this thesis was to produce scientifically well-founded suggestions on adaptation of road drainage systems to climate change involving more frequent floods. The work began by examining current practice for road drainage systems in Sweden and gathering experience from professionals working with various problems concerning surface and subsurface drainage systems. Various hydrological models were then used to calculate the runoff from a catchment adjacent to a road and estimate changes in peak discharge and total runoff resulting from simulated land use measures. According to these survey and hydrological modelling studies, adaptation of road drainage systems to climate change can be grouped into two categories: i) institutional adaptation; and ii) technical adaptation. The main approaches in institutional adaptation are to: i) raise the awareness of expected climate change and its impact on drainage systems in transport administration and relevant stakeholders; ii) include adaptation measures in the existing funding programme of the transport administration; and iii) develop an evaluation tool and action plans concerning existing road drainage systems. Technical adaptation will involve ensuring that road constructions are adapted to more frequent extreme precipitation events and responsive to changes in activities and land use in areas adjacent to roads. Changes in climate variables will have effects on watershed hydrological responses and consequently influence the amount of runoff reaching roads. There is a great need for tools such as hydrological models to assess impacts on discharge dynamics, including peak flows. Improved communication between road managers and local actors in the forestry and agriculture sectors can be a means to reduce the impacts of, e.g., clear-cutting or badly managed farmland ditches. / QC 20111214

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Railway owners manage geographically dispersed networks comprising major elements of ageing infrastructure that are very susceptible to natural hazards. Consequently, transport agencies must address maintenance issues to guarantee serviceability and safety. This includes increased inspections and investing into structural health monitoring (SHM) programs. Regular SHM of existing bridges are usually scheduled during their service life to evaluate their health and as part of proactive maintenance where future deterioration is anticipated. Typically, a routine inspection consists of field measurements and visual observations made by a bridge inspector. However, disruption to civil infrastructure services due to scheduled maintenance work, visual inspection, etc. is increasing.  The main purpose of SHM is to collect information such as geometry, previous and ongoing concrete deterioration, steel rebar corrosion, water seepage, concrete cover delamination, deflections, or settlements etc. The way such data are documented is through field inspection notes, freehand sketches, and photographs. Oftentimes, the data is stored in different systems and data collection and visualization still relies on paper-based record keeping processes. In addition, the procedure is highly dependent on the inspector’s experience [1], and knowledge of the structural behavior, together with the material properties of the system being investigated. The method has its limitations in the sense that only accessible parts are investigated due to time shortage, safety issues, or the difficult terrain in which the structure is sometimes located. This is especially true for large structures, such as bridges, where investigating the whole area would be highly time-consuming and potentially unsafe [2]. Honfi et al. [3] noted that the inspection’s duration is highly dependent on the bridge span (less than 10m can amount to 0.5 days and bigger than 100 m can amount to 20 days). In addition, defects can only be detected when their presence is visible to the naked eye, so they may already affect the life of the structure. Graybeal et al. [4] noted that routine inspections have relatively poor accuracy, with the following factors affecting the reliability of these results: inspector fear of traffic, near visual acuity, color vision, accessibility, and complexity. Furthermore, knowledge transfer from one inspection period to another becomes difficult when different inspectors carry out the investigation. Therefore, there is a strong need to identify new inspection and monitoring techniques for infrastructure that, in addition to being contactless and productive, reduce disruption, and improve the efficiency and reliability of the acquired data. With the expansion of the low-cost consumer cameras, photogrammetry could play an important role in supporting SHM on existing bridges. Vaghefi et al. [5] carried out a study of 12 remote sensing technologies and their potential to detect a series of common problems on US bridges. They concluded that 3D optical technologies have potential for documenting surface-related defects. Faster bridge inspection and visualization was described when aiming to quantify the defects over bridge deck surfaces with a low cost and easily deployable technology. Other studies reported on the use of photogrammetry as alternative to traditional measurement applied in laboratory environment; a review is done by Baqersad et al. [6]. The researchers themselves have a well-proven experience in applying photogrammetry for determination of failure mechanisms in concrete structures, defect detection, and monitoring full-field deformations. In an effort, by Popescu et al. [7], to develop new monitoring and inspection methods with a preliminary study, photogrammetry and terrestrial laser scanning utilized to generate the 3D model of six railway bridges located in northern Sweden. Results have shown an acceptable performance of 3D model of existed infrastructure generated by photogrammetry. Therefore, the current project will contribute with optical alternatives to traditional SHM approaches that are low-cost, suitable for field application, and easily deployable. The results indicate that bridge inspection on generated digital model is more reliable, productive, and accessible than traditional surveys. For 3D model generation we used photogrammetry technique, which is more efficient and cost-effective compared to the laser scanning, but improvements in accuracy and automation during the image acquisition phase are still required.  The approach of autonomous defect detection performed on two case studies. Two types of defects including cracks, and block opening in a hard-to-access area was successfully detected and measured by pixel-wise mapping to an orthophoto. The proposed method has considerable potential in automated infrastructure inspection but some problems due to background noise remain to be overcome. The existence of noisy patterns such as shadows, dirt, and snow or water spots on surfaces makes damage detection very challenging, especially for the fine cracks. Overall, while the automated inspection technique proposed herein performs well, it clearly still requires supervision by a human inspector.

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Sommaren 2006 så upptäcktes ett flertal sprickor på bron över Vårby fjärden i närheten av Stockholm. Samtliga sprickor syntes ha uppstått i svetsar som förbinder vertikala livavstyvningar med huvudbalkarnas överflänsar. På uppdrag av Trafikverket så har en utredning genomförts med syftet att klarlägga orsaken till sprickornas uppkomst. Utredningen omfattande bl.a.-Töjningsmätningar på bron. -Delskadeberäkningar enligt Palmgren-Miner och utförda på basis av långtidsmätningarna-Finita element analyser-Mikroskopanalyser av bit av en svets med en sprickyta-Tester utförda på en mindre samverkansbro vid Luleå Tekniska Universitet (LTU)Resultatet av utredningen påvisar entydigt att orsaken till sprickorna är utmattning. De för utmattning relevanta spänningarna tros vara resultatet av påtvingade rotationer på styva livavstyvningar och tvärförband. Rotationerna uppstår då betongfarbanan böjer sig för tunga fordon. Med all rimlig visshet så förbisågs denna sekundära effekt när bron konstruerades.Tester på en mindre samverkansbro har utförts vid Luleå tekniska Universitet. Två olika typer av tvärförband testades. Testerna och resultatet av dessa beskrivs i uppsatsen.På basis av resultatet av Vårby-utredningen samt av utförda tester vid LTU, och med ett syfte att minska sannolikheten för liknande sprickbildningar, så har ett antal detaljutformningar utvärderats. Vidare så föreslås en enkel metod för utvärdering av kritisk spänningsvidd i livavstyvningar.

The assumptions encountered during the analysis and design of civil engineering structures lead to a difference in the structural behavior between calculations based models and real structures. Moreover, the recent approach in civil engineering nowadays is to rely on the performance-based design approaches, which give more importance for durability, serviceability limit states, and maintenance.Structural identification (St-Id) approach was utilized to bridge the gap between the real structure and the model. The St-Id procedure can be utilized to evaluate the structures health, damage detection, and efficiency. Despite the enormous developments in parametric time-domain identification methods, their relative merits and performance as correlated to the vibrating structures are still incomplete due to the lack of comparative studies under various test conditions and the lack of extended applications and verification of these methods with real-life data.This licentiate thesis focuses on the applications of the parametric models and non-parametric models of the System Identification approach to assist in a better understanding of their potentials, while proposing a novel strategy by combining this approach with the utilization of the Singular Value Decomposition (SVD) and the Complex Mode Indicator Function (CMIF) curves based techniques in the damage detection of structures.In this work, the problems of identification of the vertical frequencies of the top storey in a multi-storey¸ building prefabricated from reinforced concrete in Stockholm, and the existence of damage and damage locations for a bench mark steel frame are investigated. Moreover, the non-parametric structural identification approach to investigate the amount of variations in the modal characteristics (frequency, damping, and modes shapes) for a railway steel bridge will be presented.

Improving productivity is a central challenge in most industries and so also in construction. In many countries, such as Great Britain and US (Egan, 1998; Huang et al., 2009; Teichholz, 2001), governmental reports and research publications have highlighted the slow growth of productivity in the construction industry. In Sweden the urgency of improving productivity and client satisfaction in the construction industry have initiated a number of government investigations (SOU, 2002; SOU, 2009; SOU, 2012).A recent investigation of government clients' actions to improve productivity and innovation in infrastructure projects have recommended better planning regarding the procurements of projects, increased amount of turnkey contracts and that the sector must become more industrialized. As a response, the Swedish Transportation Administration has launched a research and innovation program where an increased industrial mindset and standardization of products is on the agenda. With the exception of the process-based housing sector, increased industrialization has however been difficult to achieve in the project-based construction industry.The aim of the research is to find the most important parts and processes that can be industrialized to make bridge construction projects more efficient. Empirical data has been collected through questionnaire surveys, workshop and case studies. The data has resulted in four appended papers with focus on mapping the concept of industrialization. Each paper contributes to the aim, but focuses on different aspects of the concept.An interesting aspect of the empirical results from the research is the multi-facetted view practitioners and industry experts have on industrialization, a concept involving elements like prefabrication, standardization and processes. Many of the identified core elements of industrialization focus on processes (long-term) rather than projects (short-term). Some major barriers for industrialization are identified involving: lack of repetition possibilities, strict norms and rules, Design-bid-build contracts, government regulations, and the existing conservatism in the infrastructure sector. Interesting is that out of the five largest barriers, three could be traced back to the client role. As such, the clients (i.e. STA in Sweden) must address these barriers in order to enhance increased industrialization. Launch of the long-term research and innovation program by STA, where increased industrialization throughout the value chain and standardization of products are on the agenda, is a first step toward breaking down barriers, hence possibilities for increased productivity. Standardization of parts and products is shown to be a possible way of decreasing complexity related to on-site construction. Case studies have shown that massive saving in terms of time can be achieved utilizing prefabrication instead of traditional on-site construction. But standardization and prefabrication will not be more common as long as identified barriers like aesthetics issues and assumptions that quality is decreasing are available among practitioners. Also the small chances for large-scale production and repetitiveness are hindering standardized parts and products to be more commonly used.The general conclusion of this research is that massive savings in terms of time can be achieved when utilizing more industrialized methods and techniques during construction of concrete bridges, but barriers have to be dealt with before long-term productivity increases can be achieved.