Quality control and quality assurance of pavements is today primarily based on core samples. Air void content and pavement thickness are parameters that are evaluated. However, no parameter connected to the stiffness is evaluated. There is a need for fast and reliable test methods that are truly non-destructive in order to achieve an effective quality control and quality assurance of pavements. This licentiate thesis presents surface wave testing using air-coupled microphones as receivers. The measurements presented in this work are performed in order to move towards non-contact measurements of material stiffness. The non-contact measurements are compared to conventional accelerometer measurements in order to compare the noncontact measurements to a “reference test”. The two appended papers are focused on evaluating one parameter in each paper. In the first paper all equipment needed to perform non-contact measurements are mounted on a trolley in order to enable measurements while rolling the trolley forward. It is shown that rolling measurements can provide rapid and reliable measurements of the Rayleigh wave velocity over large areas. However, the measurements are shown to be sensitive to misalignments between the microphone array and the measured surface. An uneven surface can thus cause major errors in the calculated results. The second paper presents an alternative method to evaluate the thickness resonance frequency of a concrete plate. It is demonstrated how the established Impact Echo method can give erroneous results when aircoupled microphones are used as receivers. Instead a method based on backward wave propagation is introduced. It is demonstrated how waves with negative phase velocities can be identified in a narrow frequency span close to the thickness resonance. / <p>QC 20141128</p>

Majoriteten av de svenska betongdammarna uppfördes under 1900-talet och börjar därför närma sig sin uppskattade livslängd; 50-160 år. Några av dessa betongdammar används för att utvinna vattenkraft. Vattenkraft är Sveriges största energikälla och utgör ca 45% av vår totala elproduktion. Det ställs därför krav på att reparera samtliga betongdammar inför fortsatt förvaltning och för att bibehålla vår elproduktion. Betongdammar sammanlänkas med hjälp av dilatationsfogar. Dilatationsfogar hjälper betongkonstruktionen att stå emot de rörelser som sker under temperaturvariationer. På grund av dilatationsfogens placering i konstruktionen så är det väldigt svårt att genomföra och säkerställa en reparation. Inuti dilatationsfogens plåtfogbandskanal, i fallen där dilatationsfogen besitter två fogband, används bitumen som ett vattenstopp. Varje dilatationsfog som tätas med bitumen genererar en klimatpåverkan om ca 0,5 till 1,5 kg CO2-e per fog. Om fogbanden, inom dilatationsfogen, eller betongen i närheten av dessa skadas så kan därav bitumen lackas ut och följa med vattnet nedströms. Om detta sker så genereras en ökad miljö- och klimatpåverkan. Då nytt material måste produceras för att avlasta bitumenförlusten, fogbanden måste reparareras och bituminet släpps ut i naturen. Därför är det även av intresse att minimera eller helt ta bort det nuvarande vattenstoppet av bitumen.   I ett försök att minimera komplexiteten och trappa ned på bitumenanvändningen undersöks i detta examensarbete en reparation med hjälp av bentonitpellets. Reparationen sker via ett borrhål som sedan återfylls med bentonitpellets. Det finns två betongdammar i Sverige som använt sig utav denna metodik. Examensarbetet syftar således till att utvärdera hur denna reparationsmetodik står sig, dels längre fram i tiden, mot andra alternativ och framtida förväntningar om att eventuellt kunna ersätta bituminet mot andra material. Inledningsvis undersöktes bentonitpelletsens svällförmåga samt hur materialet ansamlar sig fukt. Detta genom nya framtagna metoder, som delvis, är baserade på tidigare standarder. Med hjälp utav dessa nya metoder kunde materialegenskaper också utvärderas mer långsiktigt. För att utvärdera långtidsperspektiv tilläts bentonitpelletsen att genomgå frostcykler i ett temperaturväxlingsskåp. Där fem dygn i temperaturväxlingsskåpet, uppskattningsvis, motsvarar de svenska klimatförhållanden i norra Sverige som förväntas inträffa under ett år. Bentonitpelletsen utvärderades sedan via samma testmetodik efter 1,5 och 3 år. Resultatet från bentonitpelletsens fuktupptagningsförmåga visade på en skillnad mellan de olika sorterna. Den rena Na-bentonitens fuktupptagningsförmåga står sig bättre med tiden, jämfört mot de kemiskt framställda Na-bentonitpelletserna. Resultaten från svällförmågan tyder dock på att samtliga bentonitpellets upplever en försämring allt eftersom. Om vattenkvoten är låg innan frostcykler så ökar bentonitpelletsens svällförmåga, på grund av att den uttorkas. Efter den första experimentella delen, och insamlade materialkunskaper från denna, uppfördes en miniatyrversion av en verklig dilatationsfog. Bakgrunden till detta genomförande var att man ville undersöka hur stort tryck som bentonitpelletsen klarar av att hålla tillbaka innan materialet går till brott. Vattenfalls konstruktörer uppförde testriggen och denna bestod främst utav plåt. En delad betongkub, med ett hål i mitten, placerades i konstruktionen. Hålet fylldes därefter upp av bentonitpellets. För att kunna åskåda hur materialet betedde sig under tryckförsök bekläddes konstruktionens ovandel med plexiglas. På denna plexiglasskiva installerades en manometer. Med hjälp av manometern, och ett konstant inflöde av vatten, kunde trycket i testriggen uppmätas och regleras. När den sedimenterade bentonitpelletsen går till brott så sjunker trycket på manometern. Resultatet från tryckförsöken visar på ett samband mellan bentonitpelletsens deklarerade svälltryck och det tillförda vattentrycket. Beroende på inflödet kan en reparation med bentonitpellets maximalt klara av att hålla tillbaka ett tryck motsvarande 5 till 12 höjdmeter av vatten – där det exakta värdet baseras på tiden den tillåtits att sedimentera. Dessa värden gäller för dess initiala förmåga. Hur materialet står emot vattentryck längre fram i tiden behöver fortsatt utvärdering. Baserat på studiens resultat så kommer inte den tidigare genomförda reparationen, i en av betongdammarna, att hålla – eftersom denna reparation överstiger 12 höjdmeter. Baserat på informationen som presenterats i denna rapport råder det en fortsatt osäkerhet om bentonit kan användas i betongkonstruktioner. Området kräver således fortsatt forskning för att säkerställa dess långsiktiga hållbarhet inom betongkonstruktionen. / Most of Sweden’s concrete dams were built during the 1900’s. Therefore, they are starting to reach the estimated end of their life-cycle; 50-160 years. Some of these concrete dams are used for hydroelectric purposes. Hydroelectric power is one of Sweden’s primary source for electricity, which approximately makes for 45% of our total electric production. Hence, the need for reparation is increasing for further management and maintaining our electricity production in these concrete dams. Concrete dams are linked by expansion joints. These expansion joints help to reduce the stress, during swelling and shrinking, in the concrete caused by temperature variation. Due to the placement of these expansions joint, they become difficult to repair as well as ensuring the success of a reparation. Inside the expansion joint there are dimbands. The dimbands can be sealed with bitumen to help their water stopping abilities. For every expansion joint that is sealed with bitumen the estimated climate impact is 0,5 to 1,5 kg CO2-e per joint. If the dimbands, inside the expansion joint, or the surrounding concrete gets damaged or breaks the bitumen varnishes downstream. This generates for an increased environmental and climate impact, due to the need for new bitumen and steel to fill and seal the leak and oils being released into the surroundings. Therefore, it is also of interest to reduce the usage of bitumen or remove it completely from these dimbands. To minimize the complexity and reduce the usage of bitumen this thesis will evaluate a reparation method with bentonite pellets. The reparation method consists of a borehole, which is then backfilled, with bentonite pellets. There are two concrete dams in Sweden which have used this method. Therefore, this thesis work also aims to evaluate how this reparation will last, regarding time, against other options and future expectations regarding the replacement of bitumen. To begin, the bentonite pellets where first evaluated based on their swelling capabilities and moisture absorption. These attributes were tested by new methods, which are partly based on previous standards. These new methods for the material properties also allowed for long-term evaluation. To evaluate how the bentonite pellets would react over time they were placed in a temperature change cabinet. Five days in these cabinets, were assumed to, correspond to the Northern Swedish climate changes that takes place over a year.  The bentonite pellets were then evaluated by the new methods after 1,5 and 3 years. The results, for both swelling and moisture absorption, showed a difference depending on the bentonite type. The pure Na-bentonite moisture absorption has better absorption capabilities over time, compared to chemically produced Na-bentonite. The results from swelling shows that, regardless of bentonite type, they all induce worse swelling capabilities over time. Although, if they begin thawing cycles at a lower water content their swelling capabilities increases due to the bentonite experiencing exsiccation.  After the first experimental part, and this newly gathered material knowledge, a miniature version of a concrete dams’ expansion joint were built. The background to this was to research how many altitude meters (mVp) the bentonite pellets could withstand before collapse. Vattenfalls engineers built the testrigg, expansion joint, which primarily consisted of steel. A splintered concrete cube, with a predrilled hole in the middle, was then placed in this steel cartridge. The hole was then filled with bentonite pellets. To see the sequence of the material reaction during pressure tests the testrigg had a top of plexiglass. A manometer was then attached to the plexiglass. The manometer, and a consistent flow of water, allowed for the pressure to be monitored and regulated. When the sedimented bentonite pellets collapses the pressure drops.  Results from the pressure tests show a correlation between the bentonite pellets declared swelling pressure and the externally supplied water pressure. Depending on the inflow the bentonite pellets can withstand a pressure between 5 to 12 meters of water height – where the exact value is given by the time it is allowed to sediment. These values only consider the initial expansion of the material. Further research is required to evaluate how much water pressure the material can withstand over time. Based on the findings of this study one of the previously repaired concrete dams’ bentonite seal will collapse in due time, since the reparation exceeds 12 meters in height. Based on the information provided in this thesis it is difficult to decide whether a bentonite seal will be beneficial for the concrete structure. Further research is required to ensure the sustainability of using bentonite inside concrete structures.

During the last years the number of installed PV-modules have increased significantly. As a result, the self-consumption of the solar electricity has become more important. One way to increase the self-consumption is to install an energy storage, for instance a battery. Another way is to introduce a physical energy community. An energy community is a way to share energy, in this case local produced renewable energy from the PV-panels, between buildings in a local electrical-grid.  The aim of this project is to investigate how the self-consumption change when an energy community is introduced and explore differences depending on the heating system of the building. This energy community includes seven buildings, two buildings with district heating and five buildings with heat pumps. An economic analysis of the economic benefits of energy communities is also included. The project is conducted as a case study of a new block that is under construction in Örebro. A building simulation have been performed in IDA ICE 4.8 SP2. This includes simulations of energy consumption and energy production from PV-modules. The battery model is done in Matlab and used to simulate different battery sizes. The self-consumption increases when an energy community is established for all the individual buildings no matter of the heating method. For buildings with heat pump, the self-consumption was higher than it was for the buildings with distric-heating. The district heated building with the lowest self-consumption as an individual building increased its self-consumption from 66.7% to 72.5% when joining an energy community with only one other building. For building with heatpump the lowest self-consumption was 82.5% and in an energy community the self-consumption increased to 92.6% From an economic aspect it is a good idea to establish an energy community regardless of size and type of heating method that is used in the buildings. For all communities the repayment period for the PV-modules is shorter for the community than it is for the individual buildings. However, to install a battery for the community is not profitable if you only load the battery when there is an overproduction from the PV-modules compared to the need from the load.

Bridge design and construction practice in former USSR, especially Russia, is not much known to the foreign engineers. Many advanced structural theories and construction practices have been established. In 1931, Franklin D. Roosevelt said, “There can be little doubt that in many ways the story of bridge building is the story of civilization. By it, we can readily measure a progress in each particular country.” The development of bridge engineering is based on previous experiences and historical aspects. Certainly, the Russian experience in bridge engineering has its own specifics. Bridge design proceeds in accordance with local standards and specifications. This study considers the basic rules and standards in bridge design in the North of Russia, the work includes the overview of Russian design concepts. The paper shows the design of typical concrete bridges including all calculations and analyses for future bridge stability and also drawings for visualisation. The results of the work are conclusions based on performing the required design calculations, drawings, preparing a final estimate and preparations for the construction. There are also some notes concerning the Russian design systems, computer programs for designing and computing and, finally, comparison of the Russians design standards and the Eurocode.

The current interest in energy saving asphalt production techniques is great and several new processes have been developed to reduce the mixing and compaction temperatures for hot mix asphalt. In particular, mastic asphalt products (Gussasphalt) require high working temperatures, and harder requirements concerning bitumen fumes and carbon dioxide emissions have been introduced for such products. Consequently, the need of a new means of producing and placing mastic asphalt at lower temperatures is particularly large. One way of reducing asphalt mixture temperature is by using special flow improving additives like wax. This technique has successively been tried in several studies for polymer modified mastic asphalt used for bridge decks and parking areas in Sweden. However, there still are uncertainties about possible negative impact on crack susceptibility at lower temperatures due to the addition of wax. In this study, 4% montan wax (Asphaltan A) was used for one particular polymer modified mastic asphalt product. Type and amount of wax additive was selected based on results from earlier studies. The impact on binder, binder/filler mixtures and mastic asphalt from production was tested in the laboratory, focusing on low temperature performance. The bending beam rheometer (BBR) was used for determining low temperature creep compliance and the tensile stress restrained specimen test (TSRST) for determining fracture temperatures. Binder properties were determined using dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy and conventional tests (softening point, penetration, elastic recovery, Fraass breaking point, viscosity and storage stability). Aging was performed using the rolling thin film oven test (RTFOT) at 200°C. As expected, the addition of wax to the polymer modified binder showed a viscosity reduction at higher temperatures, corresponding to a similar positive effect of more than 10°C on production and laying temperature for the mastic asphalt. DMA and BBR results showed some increase in stiffness and a more elastic response of the wax modified binder at medium and low temperatures. The TSRST fracture temperature was 5 °C higher for the mastic asphalt containing 4% wax, indicating however no dramatic negative impact on crack susceptibility.

Research performed on the subject of dynamic soil-structure interaction (SS) concerning railway bridges is presented in this thesis with the focus on simply supported railway bridges supported by shallow foundations in soil strata on bedrock. The research aims to obtain insight into the SSI of high-speed railway bridges and to provide recommendations on how to model the soil-bridge system from a design perspective. A three-dimensional (3D) simply supported soil-bridge model was first developed and the effects from model assumptions made on the soil-foundation system was evaluated in a 3D setting (paper I). The soil-foundation system was then refined and a model assumptions study was performed in order to evaluate the effects of model assumptions on impedance functions, including the influence of the permanent load acting on the soil-foundation system (paper II). Finally, a study of the assembled soil-bridge system was performed in an extensive parametric study including a set of 2D bridge models in combination with a set of shallow foundations in soil strata on bedrock (paper III). A supplementary section related to paper III was also added in this thesis, showing the effects of the substructure mass. The model assumptions made when creating the soil-foundation model and the soil-bridge model can be very important and must be made with care. The permanent load acting on the soil-foundation systems of shallow foundations may alter the impedance functions significantly. The substructure mass may alter the behavior of the soil-bridge system depending on its magnitude, and neglecting it gives inaccurate results. The 3D effects of SSI do not cause high vibrations due to modes other than the first bending mode, and assuming a 2D bridge model is generally acceptable. The effects of SSI on the soil-bridge systems with shallow soil strata are largely dependent on the ratio between the natural frequency of the bridge and the fundamental frequency of the soil. Depending on the value of this ratio, the effect of including SSI in bridge models may contribute to the bridge obtaining a negligible, conservative, or non-conservative response, as compared to the bridge with the assumption of non-flexible supports. / Forskning i syfte att utröna effekten av dynamisk jord–struktur-interaktion (SSI)på järnvägsbroar presenteras i denna avhandling med huvudfokus på fritt upplagdabroar med stöd av plattgrundlagda fundament i jordar på fast berggrund. Forsknin-gen syftar till att ge förståelse för interaktionen mellan jord och järnvägsbroar samtatt ge rekommendationer på hur systemet kan modelleras ur ett designperspektiv.En tredimensionell (3D) fritt upplagd jord–bromodell utvecklades först och effek-terna av modellantaganden gjorda på jord–grundläggningssystemet utvärderadesi en 3D miljö (artikel I). Jord–grundläggningssystemet förfinades och en studiegenomfördes för att utvärdera effekterna av modellantaganden på impedansfunk-tioner, inklusive påverkan av den permanenta belastningen som verkar på jord–grundläggningssystemet (artikel II). Slutligen utfördes en omfattande parametriskstudie av det sammansatta jord–brosystemet där en uppsättning tvådimensionella(2D) bromodeller kombinerades med en uppsättning jordar (artikel III). Ett kom-pletterande avsnitt relaterat till artikel III lades till i denna avhandling som visareffekterna av massan av underbyggnaden på jord–brosystemet.De modellantaganden som görs vid skapandet av jord–grundläggningsmodeller ochjord–bromodeller kan vara mycket viktiga och bör utföras med varsamhet. Den per-manenta belastningen som verkar på jord–grundläggningssystemet kan väsentligtförändra impedansfunktionerna. Massan av underbyggnaden kan vidare ändra re-sponsen i jord–brosystemet, beroende på dess storlek, och att försumma den kan gefelaktiga resultat. De 3D effekterna av SSI orsakar inte höga vibrationer på grundav andra moder än den första böjmoden, och att anta en 2D bromodell är såledesgenerellt sett motiverat.Effekterna av SSI på jord–brosystemet i grunda jordar beror till stor del av kvotenmellan brons naturliga frekvens och jordens fundamentala frekvens. Beroende påvärdet på denna kvot kan effekten av att inkludera SSI i bromodeller bidra till attbron får en försumbar, konservativ, eller icke-konservativ respons, i jämförelse medbron med antagandet om fasta upplag. / <p>QC 20200903</p>

En brotyp som är vanlig bland brokonstruktioner är plattrambron. Denna brotyp byggs både med slak- och spännarmering. Det är dock vanligare att bygga med slakarmering än spännarmering, vilket övervägs särskilt då spännvidderna är ungefär 25- 30 meter eller mer. Inledningsvis har en noggrann litteraturstudie genomförts tillsammans med en intervju av en kunnig brokonstruktör för att säkerställa en interaktion mellan teori och aktuell praxis. Detta arbete har haft ett huvudmål, vilket är att ur ett struktur- och kostnadsperspektiv jämföra och utvärdera hur behovet av slakarmering varierar i en plattrambros farbana då spännvidder varieras och betongtvärsnitt ändras. Arbetet har utförts med hjälp av finita elementprogrammet ”Brigade Standard”, vilket erbjuder en tre-dimensionell strukturanalys. Fyra olika tvärsnitt för spännvidder mellan 10-20 meter analyseras. Dimensioner på brodelar bestäms med hjälp av tumregler samt generella råd från intervjuperson; höjd i fält enligt L/20, L/25, L/30 samt L/35, där L är spännvidden. Resultatet visar främst att för ökade spännvidder mot 20 meter ökar lasteffekten på grund av egentyngd drastiskt och då särskilt det tvärsnitt som är störst, det vill säga L/20. Vidare visas även att slankare tvärsnitt resulterar i aningen högre armeringsmängd. Dock påverkas betongkostnaden i större utsträckning av slankare tvärsnitt och särskilt större spännvidder. Även om större spännvidd och slankare tvärsnitt föranleder ett större armeringsbehov, fås en lägre totalkostnad. Det bör noteras att priset på betong och stål är starkt beroende av konjunktur och tillgång till material. Denna studie kan bli ännu intressantare då priset varierar kraftigt för stål och föranleder att betongpriset blir mindre dominerande än vad det är idag. Huvudprodukten från detta arbete är att med hjälp av tabeller och nya priser kunna beräkna en preliminär totalkostnad för plattrambrons farbana för olika spännvidder och hur olika tvärsnittsalternativ påverkar denna kostnad.

The purpose of this Master thesis is to evaluate the RFEM software and determine if it could be used for dynamic analyses using blast loads from explosions. Determining the blast resistance for a structure is a growing market and would therefore be beneficial for Sweco Eskilstuna if RFEM could be used for this type of work. The verification involved comparing the RFEM software to a real experiment which consisted of a set of blast tested reinforced concrete beams. By using the structural properties from the experiment project with the experiment setup the same structure could be replicated in RFEM. RFEM would then simulate a dynamic analysis loaded with the same dynamic load measured from the experiment project in two different dynamic load cases caused by two differently loaded explosions. The structural response from the experiment could then be compared to the response simulated by the RFEM software, which consisted of displacement- and acceleration time diagrams. By analysing the displacement and acceleration of both the experiment and the RFEM software the accuracy was determined, and how well RFEM preformed the analysis for this specific situation. The comparison of the displacement and acceleration between the experiment and RFEM was considered acceptable if the maximum displacement was consistent with the experiments result and within the same time frame. The acceleration was considered acceptable if the initial acceleration was consistent with the experiment result. These criteria needed to be met for the verification that RFEM could simulate a dynamic analysis. If the software managed to complete a dynamic analysis for two dynamic load cases, then the software could be evaluated which consisted of determining if the post blast effects could be determined and if the modelling method was reliable.  The acceleration from RFEM were in good agreement with the experiment test at the initial part of the blast, reaching a close comparison for both load cases after 3 ms. Then the RFEM acceleration had a chaotic behaviour reaching no similarities for the duration of the blast. The displacement managed to get a close comparison of the maximum displacement with a margin of 0,5 mm for both load cases within a 1 ms time margin. RFEM managed in conclusion to simulate a blast load analysis, the displacement and acceleration gave acceptable results according to the criteria.  With the method chosen a fast simulation was achieved and with the same model complying with two different load cases for the same model gave indication that the first result was not a coincidence. The steps taken in the modelling method was straight forward, but two contributing parameters were determined to devalue the reliability. First parameter was the material model chosen for the concrete, which was chosen to a plastic material model. The two optional material model’s linear elastic and non-linear elastic both caused failed simulations. Also, the better model for the material model would have been a diagram model which insured that the concrete lost is capacity in tension with maximum capacity, but this was not available in a dynamic analysis with multiple load increments. Which is the reason why a plastic material model was chosen for the concrete. The second reason was the movement of the beam in the supports. This data was not recorded in the experiment but was determined to be a contributing part of the test. This however gave big differences of the result depending on how much the beam could move. In the end the best possible result was chosen to comply with the first load case where the same RFEM model was used in the second test. The second load case showed just as good results as the first load case, but with the big variation in results depending on the movement of the beam in the supports made this part unclear.  For the evaluation the question if the RFEM could provide a post blast analysis needed to be addressed, where the answer is no. The failure mode was chosen to comply with the choice of modelling method which required the analysis of the plastic strain in the reinforcement bars. This information was not available using the add-on module DYNAM-PRO and could therefore not provide the answer if the model structure resisted the blast.  For future work of this master thesis is to build a model that would give a more detailed post blast analysis, where this thesis was made to test the software. For this more work would be necessary by the creators Dlubal to further improve the add-on-module, which involves more extractable results and more detailed tools when using a dynamic load case, where some important functionality is only usable in a static load case. Other than that, RFEM managed to complete the dynamic analysis, and with further improving of the modelling method a more detailed analysis can be made and then be usable in real projects in the future.

Examensarbetet utfördes i samarbete med Umeå Energi, som i sitt dagliga arbete med elnätet använder mjukvaran Digpro. Programmet har under en tid matas med värden för kablar och ledningar hämtade från andra energibolag och kabeltillverkare. I framtiden kommer användningen av solceller och elbilar att öka vilket kommer att ställa högre krav på elnätet. Felaktiga beräkningsmodeller kan skapa varmgång i kabel som förkortar livslängden och i extrema fall även kan skapa avbrott. Syftet med projektet var att undersöka vilken data som vore önskvärd att använda för att säkra korrekta beräkningar för ett framtidssäkert elnät. Målet var att ta fram en standardiserad modell för kablar, presentera förslag på val av parametrar samt att analysera och jämföra den gamla och nya beräkningsmodellens påverkan på nätet. Efter en litteraturstudie sammanställdes kabeldata från svensk standard. I dpPower (Digpro) byggdes ett mindre simulerat nät som skulle vara representativt för Umeå Energis elnät. Detta genom att använda de 20 kablar med längst geografisk längd i det befintliga 0,4 kV, respektive 10 kV nätet. Två nätberäkningar utfördes för det nya nätet, en med de gamla kabelvärdena och en med de som hämtats i svensk standard. Resultatet för märkström, korttidsström och maximal säkring för de totalt 40 utvalda kablarna och resultatet för kortslutningsström (Ik3) och kortslutning fas-nolla (Ij) för skena i nätstation, skena i kabelskåp och anslutningspunkt jämfördes mellan beräkningarna. Slutligen fördes även en diskussion kring möjliga korrektionsfaktorer. Mycket av resultaten tyder på att nätet idag överbelastas. Resultaten visade att för de flesta kablar som undersökts i detta projekt har en för hög märkström angetts i Digpro, både för 0,4 kV-kablar och 10 kV-kablar. För lågspänningskablarna innebar värdena hämtade från svensk standard en minskning på 31% jämfört med de värden som fanns i Digpro sedan tidigare. För mellanspänningskablarna var motsvarande minskning 13% respektive 3%, beroende på om man räknar med en kabeltemperatur på 65°C eller 90°C. Ett annat resultat som tyder på att nätet överbelastas var att för över hälften av kablarna som undersöktes i projektet verkar säkringarna vara överdimensionerade, vilket kan leda till överhettning. Slutsatsen som dras i projektet är att Umeå Energi troligtvis överbelastar elnätet. Då det kommer att ställas högre krav på nätet i framtiden är det viktigt med en korrekt beräkningsmodell, och kabelvärden hämtade i svensk standard kan vara ett steg i rätt riktning. Korrektionsfaktorer har visat sig kunna medföra en mycket stor påverkan på belastningsförmågan, i vissa fall större påverkan än de standardiserade kabelvärdena. För mellanspänning kommer eventuell korrektionsfaktor troligtvis minska belastningsförmågan ytterligare. För lågspänning kan en sammanvägd korrektionsfaktor både över och under 1 vara möjlig, beroende på vilka förutsättningar man väljer att utgå från.

According to the climate goal set by the Swedish government Sweden will have no net emissions of greenhouse gases by 2045 (with a subgoal of decreasing) emissions from domestic transportation by 70% before 2030, compared to 2010. Because of this the vehicle fleet is being electrified and according to a prediction made by Fossilfritt Sverige 16% of the heavy vehicle fleet will be electrified by 2030. However, the electrical grid has a capacity shortage in many cities in Sweden and it will be a challenge to provide the required power. Västerås is one of those cities.    The goal of this study is to investigate the necessary electrical power in Västerås to charge city busses and freight transports in 2030, as well as look at actions that could lower the power demand. Nine places were important for charging: two depots, two public charging stations and five regions for commerce and industry, where vehicles will fast charge during loading and unloading of wares. The vehicles are predicted to stay at the loading dock for ten minutes, while they will stay in the depot and charging station for eight hours. A model created in Python was used for all nine places, as well as the bus depot, where arrival, departure and state of charge were given as input. The model then showed the power required for charging all vehicles. Load shifting was used in the depots and charging stations, and energy storages were used at the loading docks, to lower the power demand.  The result of this study shows that with direct charging of heavy vehicles 12 MW will be needed, and with load shifting and energy storages implemented the power demand would be halved.