1,721,071 research outputs found
Hoar frost formation on a salted road surface
No full textHoar frost formation may lead to slippery driving conditions during late autumn and winter time. Hoar frost formation occurs when humidity in the air deposits directly as ice on the cold road surface. To avoid slippery road during hoar frost situations, anti-icing chemicals are commonly used since they lower the freezing point of water. Unfortunately, the use of chemicals have negative impact on both cars, infrastructure and the environment surrounding the roads.
Their usage should therefore be reduces as much as possible, without raising the risk of accidents. The work of this thesis has been to investigate the process of hoar frost formation on salted road surface. A laboratory setup simulating hoar frost formation has beed developed as a part of this work. It consists of an open loop wind tunnel where warm humid air is forced to flow over a cold stone surface. The setup has shown to be able to simulate hoar frost conditions similar to those reported onsite with sufficient stability on critical parameters, such as temperatures and air humidity.
It is suggested to spilt the process of hoar formation on a salted road surface in two parts, the dilution process and the freezing process. The dilution process occurs from the solution is applied on the road surface until it is diluted to its freezing concentration at the road surface temperature. The time it takes is denoted as the dilution time. The freezing process occurs from the point the freezing concentration is reached until the ice formation results in slippery road conditions. The time it takes is denoted as the freezing time. The time froma chemical is applied on the road surface to the road becomes slippery is denoted the protection time, and it is the sum of the dilution time and the freezing time. Both parts of the process were studied.
The dilution process was studied for solutions ofNaCl, CaCl2 andMgCl2. The over all finding was that the presence of anti-icing chemical on the road surface did affect the rate of humidity transport. The presence of anti-icing chemicals did increase the rate up to 30% compared to a surface without chemicals, but the effect diminished during the first two hours as the solution got diluted.
The freezing process was examined for a solution of NaCl. The freezing process was found to start in the top layer of the solution, even though it is colder in the solution/stone interface. This indicates that there is was concentration gradient in the solution due to slower diffusion of water in the salt solution than in the air. A considerable amount of ice could be present on the salted road surface before the ice got strong enough to withstand the simulated mechanical load of traffic. For a film thickness of 0.06mmof 10% NaCl solution, the critical ice fraction was found to be 0.67. For higher ice fractions the ice was not removed by the pendulum. The critical ice fraction was found to depend on the amount of solution applied, and an ice fraction up to 0.81 was acceptable for an applied film thickness of 0.1 mm.
The increased mass flux due to the presence of chemicals contributes to a reduction in the protection time. Opposite, the critical ice fraction contributes to an extension in the protection time. Calculations have shown that by including the freezing period, the total protection time is more than 3 times longer than estimated when assuming that the protection time ends when the freezing concentration is reached. When including the increased mass flux in the dilution period, the total protection time is reduced by only 5-7% of the protection time calculated without the increased mass flux
The effect of rolling resistance on winter cycling
Get PDFAuthorities in many countries facilitate increased bicycle use in urban areas due to its numerous benefits. Still, the number of bicycle trips drops drastically during the wintertime, especially in areas with harsh winters. Inclement road conditions have been identified as a significant "barrier" to winter cycling. Moreover, previous research has found that better winter maintenance can significantly increase winter cycling. Quantitative knowledge about how the road conditions affect winter cycling is needed to improve winter maintenance and evaluate its costs and benefits. A quantifiable metric that describes the road condition quality would be helpful to investigate this correlation. A quantifiable metric that describes the road condition quality would be helpful to investigate this correlation. Rolling resistance equals the energy needed for a wheel to roll over a surface at a constant speed. It is directly dependent on surface irregularities and road contaminants such as snow or ice. Snow, ice, and uneven surfaces can all reduce cycling comfort and increase rolling resistance, making cycling more physically demanding. Therefore, rolling resistance shows potential as a valuable metric for quantifying the quality of cycleways under winter conditions.
The following work is outlined in this dissertation: A) A new measurement method for bicycle rolling resistance was developed using an instrumented bicycle. The method measured propulsive and resistive forces acting on the moving bicycle and utilized the force equilibrium to estimate the rolling resistance. B) This method was used to measure rolling resistance on various winter conditions and analyze the correlation between rolling resistance and perceived cycling comfort. C) These analyses were later used in an online survey to investigate the correlation between rolling resistance and people's stated willingness to cycle during the winter. The respondents (N=1318) based their answers on conditions shown in photos.
The results show that the developed method can measure the coefficient of rolling resistance, Crr, with a precision, represented as the standard error of the mean, of ±0.005 (1 Hz, n = 9) or ±0.002 (1 Hz, n = 55), depending on the number of recorded samples. The new method measured significant differences in rolling resistance between ten typical winter conditions. The Crr varied between around 0.01 on bare asphalt to around 0.06 in deep loose snow. The results also showed a negative correlation between rolling resistance and cycling comfort. The survey results showed that the cycling willingness among regular winter cyclists decreased close to linearly from around 90% to 19% for rolling resistances between Crr=0.01 to Crr=0.06. Summer-only cyclists showed a close to exponential decay in cycling willingness from around 70% to 7% for the same rolling resistance interval. The use of studded tires significantly increased cycling willingness while electric bicycle use did not. Low temperatures (29%) and a lack of safety (27%) were the main reasons for not cycling during the winter.
The results indicate that increased use of studded tires and slight winter maintenance improvements can increase the cycling frequency of regular winter cyclists. To recruit summer-only cyclists to winter cycling, it is necessary to provide cycleways with conditions perceived as safe and comfortable and low rolling resistance, preferably with Crr levels below 0.01
Combined Dataset for Subjective Panel Rating, International Roughness Index and Images for Road Damage Detection of Low Volume Road in Norway
No full textThe pavement condition monitoring data consists of images for a 17.2 km road section of FV216 in Innlandet County, Norway from a front view camera captured at every 20m interval.
The surveyed road section has varied road surface condition due to different resurfacing date; which varies from 2009 to 2020. Selected road stretch was divided into 36 sections of around 500m length for panel rating survey. Presented dataset also includes panel ratings and International Roughness Index (IRI) ratings for all 36 sections
ICE MELTING CAPACITY OF DEICING CHEMICALS IN COLD TEMPERATURES
Get PDFCold climates cause a great number of challenges when it comes to maintaining road conditions. For instance, snowstorms, frost and ice can all create slippery and even impassible roads. Therefore, in order to ensure vehicular mobility and general road safety, winter road maintenance requires the use of plowing and applying sand or various chemicals.
Regarding the latter method, chemicals are applied to weaken bonds in snow and ice, melt snow and ice or prevent ice from forming on the road. A deicing chemical must thus comprise several important elements, one very important element being its ability to melt snow and ice, which is also called its ice melting capacity.
Therefore in order to be able to compare and choose the proper deicing product, it is essential that one is knowledgeable about its ice melting capacity. There have been concerns for many years that the standardized method for measuring ice melting capacity, SHRP H-205.1 for solid and H-205.2 for liquid chemicals, is not reproducible or reliable enough for research purposes. The work performed and outlined in this particular dissertation involves a) a literature review of existing ice melting capacity tests with calculations to determine their accuracy, b) an explanation as to how ice melting capacity can be calculated if the applied chemical has a known phase diagram, c) the development of a new test method for measuring ice melting capacity and determination of equilibrium concentration of deicers, and d) measurements of the ice melting capacity of common deicers in cold temperatures.
It was confirmed that the “SHRP tests” are not accurate enough for research purpose. A new method based on calorimetry, “the calorimeter” was created, and a custom-made calorimeter was built for the research purposes. The idea behind the calorimeter was to measure the amount of energy needed to prevent temperature drop when deicing chemicals are added to ice; this reading can then be used to calculate the amount of melted ice. The calorimeter showed a great improvement in accuracy compared to earlier test methods. It was able to produce accurate results for solutions in cold temperatures; between -0.001g to 0.016g, which is an absolute error from 97% to 115% and an average error of 4%. The calorimeter was used to study the ice melting capacity of NaCl, MgCl2, CaCl2, CMA, KFo and sugar, both as individual chemicals and as additives to NaCl at -18°C. The test revealed the huge difference in melting capacity between solid and liquid chemicals (solutions). The ice melting capacity of the solutions was only 3% – 10% of the solid ice melting capacity. Moreover, out of all the tested chemicals, brine (23% NaCl solution) had the lowest melting capacity except for sugar, which froze at -18°C. However, in a solid state NaCl was the chemical having the highest ice melting capacity, performing 31% better than the chemical coming in second place, calcium chloride (CaCl2-2H2O). Further, as an example, the results were used to calculate application rates for a thin ice layer (0.1mm) at -18°C. The application rate using solid NaCl was within normal ranges, about 30g/m2. However, it was unrealistically high when using solutions. Using MgCl2, CaCl2, CMA, KFo or sugar as additives to NaCl in a solid state decreased the ice melting capacity of NaCl. Using chloride solutions (MgCl2 and CaCl2) as additives to brine resulted in a melting capacity between the melting capacity of the components, the improvement was dependent on the amount of MgCl2 or CaCl2. However, different results were produced by using KFo and CMA; KFo had a destructive influence on the ice melting capacity when mixed with brine, while CMA produced higher ice melting capacity than what the two components had individually. Nonetheless, the ice melting capacity was still very low.
The general conclusions of salting roads in cold temperatures, are that it is possible to achieve sufficient ice melting capacity using solid NaCl at -18°C. Used as solid, NaCl actually have relative high ice melting capacity compared to other commonly used deicers. The general conception of NaCl being “ineffective” when it is cold, must come from other qualities, e.q., low ice melting rate. Therefor, more knowledge is needed to be able to optimize the use of salt when it is cold. With temperatures below eutectic point of NaCl (-21.1°C), is the ice melting capacity of NaCl zero and should not be used. The best strategy is to dry up the road in advance to this temperature, but if the chemicals are needed the results in this dissertation implies that solid CaCl2 or KFo would be the best replacement for NaCl. If solutions are the only option (e.q., impossible to get the solid salt to lay on the road), calculations in this dissertation show that using the right concentration of solutions is crucial. With maximum solubility of MgCl2 and CaCl2 solutions, the application rate for achieving sufficient ice melting capacity in cold temperatures on a thin ice layer is approximately 150 g/m2 at -18°C, in comparison using a 20% MgCl2 and a 25% CaCl2 solution gives extreme application rates of 550 and 400g/m2.Digital fulltext not availabl
Snow adhesion mitigation on building integrated photovoltaics
Get PDFSolar energy is one of the main environmentally responsible forms of energy production and one that is very interesting for private citizens to invest in. The cost for private citizens to invest in solar energy, however, has still not reached parity with fossil fuels such as natural gas.
Integration of photovoltaic cells in building skin elements such as roofing or wall cladding, however, makes it possible to co-invest in both simultaneously. This may allow for a dramatic energy price reduction while maintaining the original aesthetics of the architecture.
In the cold regions of the world, where snow and ice are common occurrences, these present another challenge by accreting on the solar panels. The winter months, when snow and ice is most prevalent, is also the time when the energy is most needed. Though it is the least productive time of the year, between 1-20% of the annual production may be lost due to accumulation of ice and snow covering the solar panels.
Based on a thorough state-of-the-art analysis, resulting in two review articles, it was determined that snow adhesion differs fundamentally from ice adhesion. Snow adhesion is a less explored area, often conflated with ice adhesion. The scope of this thesis was therefore narrowed from including both ice and snow adhesion mitigation, to focus specifically the mitigation of snow adhesion.
In order to explicitly test the similarities and differences between ice adhesion and snow adhesion, a controlled method for snow adhesion measurement was developed. This method was then applied to known ice adhesion mitigating surfaces to ascertain the extent of the difference in behavioural trends. It was found that the level of ice adhesion mitigation has no apparent bearing on the level of snow adhesion.
The method was further applied to glass surfaces of varying roughness to begin the process of accumulating quantitative adhesion data specific to snow, and to test the limitations of the method. Results indicate that increased surface roughness on glass in the micrometre scale will have a drastic negative impact on snow adhesion mitigating efforts.
All analyses of snow adhesion were performed using synthetic snow. The use of synthetic snow allows for repeated production of snow with identical properties, something that cannot be attained with in-situ measurements using natural snow. This ensures the reproducibility of the experiments such that results may be independently verified.
After having determined that snow adhesion should indeed be studied separately from ice adhesion, a suggestion for a redefined terminology was presented, along with a framework for classification of performance
Salting during snowfalls - how little is enough to prevent snow compaction?
Get PDFDuring snowfalls, snow fallen on roads gets compact by traffic and can form an extremely slippery and dangerous road surface. The objective of winter maintenance operations is to ensure road mobility and traffic safety. Typical winter maintenance operations during snow falls are mechanical removal of snow (snow plowing) and altering the snow by the use of de-icers. The most commonly used de-icer is the sodium chloride (NaCl). The use of NaCl is economically demanding as well as detrimental for water and vegetation lying alongside the road surface. In recent years in Norway, more than 250,000 metric cubic tons of NaCl have been applied on roads during winter time. Therefore, there is a growing desire among road agencies to optimize the use of salt on roads without compromising traffic safety. To accomplish this goal, more knowledge is required on the influence of NaCl on the mechanical properties of snow. The focus of this thesis is on the optimization of salt in order to prevent snow compaction during snowfalls. In order to optimize the amount of NaCl used during snowfalls, the way salt affects snow and tire-pavement interaction must be better understood. More specifically, the minimum amount of salt that is needed to bring snow in a weak, cohesionless state is still to be determined.
To my knowledge, the application of salt is mainly based on the experience of winter maintenance personnel and not scientifically based. Therefore there is a need for more knowledge on salted snow and its behavior during mechanical actions.
With indoor and outdoor studies, this thesis aimed to understand the behavior of salted snow under the effect of tire compression and explored applicability of this knowlegde in realistic conditions.The behavioral understanding of snow mixed with diluted NaCl aqueous solution provided in this thesis are:
·For a given load, the snow containing NaCl solution gets compressed to a higher density, compared to snow without NaCl solution. A solution content of 10 wt.% inside the snow increased the density of the snow crystals with up to 30%, compared to pure snow. Beyond 10 wt.% solution content, the density of the compressed snow does not increase but it flattens out.
·Despite the higher density, the presence of NaCl aqueous solution weaken the compressed snow. An solution content of 5wt.% - 10 wt.% is able to substantially reduce the strength of ice in grain-grain contact, such that snow is easily removed mechanical action.
·During the mechanical compression, the presence of NaCl solution increased significantly the flowability of the snow. With 10 wt.% solution content the amount of snow that was squeezed out of the contact area of a rolling test tire (7.2 km/h) increased by more than 50 %, compared to pure snow. Further increase in solution content (up to 40 wt.%) does only slightly increase the squeeze out.
·The field investigation suggest that a solution content of 5-10 wt.% (diluted) NaCl solution is enough to prevent compacted snow formation. 10 wt.% was enough to get the snow removed by the effect of 20 vehicle passes, whereas 5 wt.% was enough to remove the snow by a scraping blade. These estimates are considered conservative as they were obtained under conditions of that create most severe snow compaction (slow driving, close to 0°C).
·The minimum amount of salt (in g/m2) is calculated for a given snow fall, using the criterion of 5 and 10 wt.% NaCl solution content. To determine an actual application rate, a safety factor remains to be determined to account for salt loss during and after spreading
Tilstandsregistrering av renhold i vegtunnel
No full textDet finnes over 1100 vegtunneler i Norge i dag. Tunnelvask er en viktig del av driften av tunnelene da det holder tunnelene lyse i tillegg til at det forlenger levetiden på teknisk utstyr. I dag styres hyppigheten av tunnelvask periodisk i henhold til krav fra Håndbok N500. Det er ønskelig å se på om en tilstandsregistrering av renhet kan danne grunnlaget for tilstandsbasert tunnelvask. Dette gjør at man kan planlegge vask etter behov, noe som kan redusere kostnadene knyttet til vask og stengte tunneler.
Det er gjennomført en litteraturstudie som omfatter tunneler og krav til renhold, kamera og lysmåling. Deretter har det blitt utviklet en metode for analysering av renhet basert på bilder. Metoden er implementert i Strindheimtunnelen i Trondheim der det ble utført forsøk ved å ta bilder med et speilreflekskamera gjennom frontruta på en bil kjørende i forskjellige hastigheter igjennom en tunnel tunnel både i forbindelse med og i etterkant av tunnelvask. Bildene i forsøkene er tatt med ulike kamerainnstillinger: ISO, lukkertid og blenderåpning. Hensikten med forsøkene har vært å finne områder i tunnelen som er egnet for analyse samt en optimal kombinasjon av kamerainnstillinger.
I studiet er det foreslått lysstyrkehistogram som metode for analysering av renhet, og det ble gjennomført renhetsanalyser på vegg, lysarmatur og skilt ved hjelp av denne metoden. Det kom frem at det kun var ved å se på lysarmaturene at det var mulig å stadfeste at det var blitt mer skittent etter fire uker drift i tunnelen. Resultatene fra analysene på tunnelvegg og skilt viser at tunnelen hadde blitt lysere. Det er også funnet at værforhold og tid på døgnet har stor påvirkning på resultatene.
Forskningsarbeidet viser at god bildekvalitet avhenger av flere parametre og at om et bilde er brukbart til analyse avhenger både av valgt område og bildekvaliteten. Ved å bestemme analyseområde kan kamerainnstillinger og hastighet optimaliseres for det gitte området.
Resultatene fra denne studien viser at metoden kan brukes til å vurdere renhet og dermed danne grunnlaget for tilstandsbasert tunnelvask. Det er flere faktorer som begrenser metoden før den kan gjennomføres i praksis, som utfordringer med belysning og stedfesting av bilder. Disse utfordringene kan eksempelvis løses ved å ha kunstig belysning på analyseområdet, og etablere dedikerte felt i tunnelen til bildetaking. Dette er områder det kan forskes videre på
Kan 3D modeller bidra til bedre drift og vedlikeholdsinnspill i planprosessen?
Get PDFEn vegs livsløp består av flere faser; planleggingsfasen, byggefasen og driftsfasen. I hver av fasene er det flere prosesser som må utføres før vegen skal bil til. Hver prosess skal kvalitetssikre vegens trase og utforming. Videre skal vegen fungere på en god og trafikksikker måte, og det er derfor viktig at det planlegges slik at drift og vedlikehold kan utføres på en optimal og effektiv måte igjennom hele året. I håndbok N100 (Statens vegvesen, 2019) står det at «Veg- og gateanlegg skal utføres slik at drift og vedlikehold kan utføres effektivt og sikkert». Det er altså et krav om å ta hensyn til drift og vedlikehold når vegen planlegges. Retningslinjene sier derimot lite om hvordan dette kan gjøres, og det er opp til vegplanleggeren å inkludere det i sitt arbeid.
I litteraturen er det funnet en del publisert litteratur om viktigheten av drift og vedlikehold i planfasen, men hvordan drift og vedlikehold skal inkluderes er ikke beskrevet på samme måte. Statens vegvesen (Statens vegvesen, 2018) påpeker i håndbok R760 viktigheten av å komme tidlig inn i vegprosjekt. Jo tidligere en kommer inn i vegprosjektet, jo større er muligheten for å påvirke prosjektet uten at kostnadene øker nevneverdig. Staten vegvesen har også laget en erfaringssamling (Statens vegvesen, 2013), hvor gode og dårlige drift- og vedlikeholdsløsninger blir presentert med både bilde og kommentarer. Etter inspirasjon fra jernbanen, har Vegdirektoratet utviklet RAMS-analyser for både tunnel (Vegdirektoratet, 2015) og veg i dagen (Johansen, 2019), slik at prosjektene sjekkes opp mot pålitelighet, tilgjengelighet, vedlikeholdsbehov og sikkerhet. På den måten kan drift og vedlikehold bli premissgivende når en ny veg skal planlegges.
I denne oppgaven skal en metode for å inkludere drift og vedlikehold i planprosessen. Formålet med studien er å undersøke om potensielle drift og vedlikeholdsutfordringer er lettere å oppdage ved å bruke en VR-modell i stedet for tradisjonelle 2D-tegninger, og hvor i planprosessen det ville vært nyttig med en slik gjennomgang. Studien kartlegger også hva det som er ønskelig og nødvendig av informasjon for at en slik gjennomgang skal være optimal.
Oppgaven tar utgangspunkt i vegprosjektet omregulering av Elgeseter gate i Trondheim kommune. I alt 17 deltakere, med ulik bakgrunn innen vegfaget, deltok i et forsøk hvor hver deltaker enkeltvis skulle utføre en drift og vedlikeholdsgjennomgang av vegprosjektet. Gjennomgangen utføres to ganger, først en gang ved å bruke 2D-tegninger og andre gang ved å bruke en VR-modell. Hver gang det ble nevnt en hindring eller en utfordring knyttet til drift og vedlikehold, ble det notert ned. Hver gjennomgang varte i maks 20 minutter. Etter at gjennomgangene var utført, ble deltakerne bedt om å svare på et evalueringsskjema. Skjemaet, sammen med antall registrerte hindringer eller utfordringer, dannet grunnlaget for videre analyse.
Det ble oppdaget 81,3% flere hindringer og eller utfordringer ved bruk av VR-modell enn ved bruk av 2D-tegningene. Videre analyse av faktorer som arbeidsbakgrunn og erfaring fra drift og vedlikehold understrekte dette. Ved å bruke VR-modell klarte en med 2-5 års erfaring med drift og vedlikehold i snitt å oppdage flere hindringer enn det en med over 20 års erfaring klarte ved hjelp av 2D-tegningene. Uavhengig av om en arbeidet hos en driftsentreprenør, byggherre/konsulent eller i en kommune, var snittet for antall registrerte hindringer omtrent det samme ved bruk VR-modellen. Ved bruk av 2D-tegninger var det derimot et stort sprik mellom driftsentreprenører og de to andre arbeidsgruppene på antall registrerte hindringer.
Svarene fra evalueringsskjemaene forsterket svarene i resultatet. Helhetsinntrykket av det ferdige prosjektet og detaljer som «blir borte» på tegningene gjorde det lettere å oppdage utfordringer knyttet til drift og vedlikehold i VR-modellen. Samtlige deltakere synes bruk av VR-modell for drift og vedlikeholdsgjennomgang kan være nyttig metode å bruke i fremtiden, og ønsket at gjennomgangen skulle utføres minst to ganger i løpet av planprosessen. En gang i reguleringsplanfasen, for å sikre tilstrekkelig areal, og en gang i byggeplanfasen, for å luke vekk dårlige valg som blir detaljert og planlagt.
Ved å se resultatene og svarene fra evalueringsskjemaet i sammenheng er det derfor tydelig at det er betydelig lettere å oppdage potensielle drift og vedlikeholdsutfordringer i VR-modellen enn på 2D-tegningene.The life cycle of a road consists of several stages; the planning phase, the construction phase and the operational phase. The first two phases includes several processes that must be done before the road is finished and the operational phase starts. Each phases must ensure the quality of the road design, to make sure that the road functions as intended. Therefore, it is important to include operations and maintenance in the planning and the construction phase. Handbook N100, from the Norwegian Public Roads Administration (2019), stats that “Roads shall be designed so operation and maintenance can be preformed efficiently and safely”. This means that maintenance and operation factors are required focus when planning roads. However, the guidelines does not say how this should be done.
There are published a lot of operation and maintenance literature. Some includes the planning phase, like the Norwegian Public Road Administrations handbooks. In handbook R760 (Statens vegvesen, 2018) it’s pointed out the importance of early involvement of maintenance and operation in road projects. The earlier the involvement the easier it is to change a solution without increasing the cost. In 2013 the Norwegian Public Road Administration (Statens vegvesen, 2013) made a collection of good and poorly solutions in the maintainability and operation perspective. The idea was to use the collections of experience to help the road planners to choose good solutions. Following inspiration from railway, the Directorate of Public Road has developed RAMS-analyses for tunnels (Vegdirektoratet, 2015) and roads (Johansen, 2019) to make sure the projects are reliable, available, maintained and safe to use. This makes sure that operation and maintenances factors become a priority in planning of a new road.
This thesis includes a new method to involve operation and maintenance in the planning phase The purpose of the study is to investigate whether potential operation and maintenance challenges are easier to detect by using a VR-model instead of traditional 2D-drawings, and to see where such a review can be included in the planning phase. The study also identifies which information that is necessary in order to do the review properly.
The thesis is based on a reregulation of Elgeseter street in Municipality of Trondheim. The experiment had 17 participants, who had different backgrounds in the road industry. Each participants did the experiment individually, where they should do a review of the road project with focus on operation and maintenance. The review was done twice, once using 2D-drawings and a second time with using a VR-model. Once a operation and maintenance challenges was discovered, it was written down. Each review lasted a maximum of 20 minutes. After, the participants were asked to fill out an evaluation form. Together, the evaluation form and the number of challenges registered, form the basis for further analysis.
In total, more than 81.3% challenges, tide to operation and maintenance, were found when using VR-model instead using 2D-drawings. Further analysis of different factors as work background or experience from operations and maintenance, emphasized it. By using the VR-model, could a person with 2-5 years of experience on averages discover more obstacles than what a person with over 20 years of experience could by using 2D-drawings. Regardless one worked at an operation contractor, aa a consultant or in a municipality, the average number of barriers registered were pretty much the same when using VR-model. By using 2D-drawings there quite a different between the average number of barriers registered between working at an operation contractor and the other two working groups.
The responses from the evaluation forms reinforced the results. The overall impressions of the finished project and details that easily “gets lost” in drawings were two things the participants mention that were easier to detect in the VR-model. All of the participants found that using the VR-model for an operation and maintenance review of the project could be a useful method in the future, and the review should be done at least twice in the planning process. Once in the zoning phase, to ensure sufficient area of operation and maintenance chores, and once in the construction phase, to ensure good solutions when the last details are planned.
By looking at the results and the responses from the evaluation forms together, it is clear that is considerably easier to detect potential operations and maintenance challenges and obstacles when using a VR-model than using 2D-drawings
Effects of temperature and prewetting on deicing performance of sodium formate
No full textDe to vanligste produkter brukt til avising på norske flyplasser er Aviform S-Solid, et granulat som består av 98% Natriumformiat (NaCOOH), og Aviform L50, en 50% løsning av Kaliumformiat (KCOOH). Tidligere forskning har utviklet flere metoder for å kvantifisere ytelsen til avisningsprodukter, men med liten tilknytning til forhold i felt. I tillegg er de fleste eksperimenter som blir utført, fokusert på isfjerningsprodukter som vanligvis brukes på veg, slik at kunnskap om formiater er begrenset. Denne artikkelen har som formål å utvide kunnskapen om hvordan ulike forhold, spesielt temperatur og tilgang til befuktningsvæske, påvirker ytelsen til formiater. Her blir det presentert en ny metode for å beregne utviklingen av smelteprosessen og penetrasjonen basert på bildeanalyse. Atten eksperimenter ble utført, både med tørre og befuktede prøver, i tre forskjellige temperaturer (-2°C, -5°C og -10°C). Innledende forsøk viste en tilfredsstillende grad av nøyaktighet ved sammenlikning med teoretiske verdier. Denne prosedyren kan bli brukt for å følge med gjennom hele smelteprosessen, uten behov for forstyrrelser pga. manuelle målinger. Det ble funnet ut at penetrasjonsraten og –dybden er sterkt avhengig av temperatur, slik at smeltehullene var betydelig mindre ved lave temperaturer. Samtidig viste det seg at befuktning korter ned tiden det tar for at smeltereaksjonen skal komme i gang ved lavt temperatur (-10°C), mens den har ingen signifikant effekt ved temperaturer nærmere 0°C. Resultatets implikasjoner og mulige applikasjoner i feltet ble også diskutert
Kan 3D modeller bidra til bedre drift og vedlikeholdsinnspill i planprosessen?
No full textEn vegs livsløp består av flere faser; planleggingsfasen, byggefasen og driftsfasen. I hver av fasene er det flere prosesser som må utføres før vegen skal bil til. Hver prosess skal kvalitetssikre vegens trase og utforming. Videre skal vegen fungere på en god og trafikksikker måte, og det er derfor viktig at det planlegges slik at drift og vedlikehold kan utføres på en optimal og effektiv måte igjennom hele året. I håndbok N100 (Statens vegvesen, 2019) står det at «Veg- og gateanlegg skal utføres slik at drift og vedlikehold kan utføres effektivt og sikkert». Det er altså et krav om å ta hensyn til drift og vedlikehold når vegen planlegges. Retningslinjene sier derimot lite om hvordan dette kan gjøres, og det er opp til vegplanleggeren å inkludere det i sitt arbeid.
I litteraturen er det funnet en del publisert litteratur om viktigheten av drift og vedlikehold i planfasen, men hvordan drift og vedlikehold skal inkluderes er ikke beskrevet på samme måte. Statens vegvesen (Statens vegvesen, 2018) påpeker i håndbok R760 viktigheten av å komme tidlig inn i vegprosjekt. Jo tidligere en kommer inn i vegprosjektet, jo større er muligheten for å påvirke prosjektet uten at kostnadene øker nevneverdig. Staten vegvesen har også laget en erfaringssamling (Statens vegvesen, 2013), hvor gode og dårlige drift- og vedlikeholdsløsninger blir presentert med både bilde og kommentarer. Etter inspirasjon fra jernbanen, har Vegdirektoratet utviklet RAMS-analyser for både tunnel (Vegdirektoratet, 2015) og veg i dagen (Johansen, 2019), slik at prosjektene sjekkes opp mot pålitelighet, tilgjengelighet, vedlikeholdsbehov og sikkerhet. På den måten kan drift og vedlikehold bli premissgivende når en ny veg skal planlegges.
I denne oppgaven skal en metode for å inkludere drift og vedlikehold i planprosessen. Formålet med studien er å undersøke om potensielle drift og vedlikeholdsutfordringer er lettere å oppdage ved å bruke en VR-modell i stedet for tradisjonelle 2D-tegninger, og hvor i planprosessen det ville vært nyttig med en slik gjennomgang. Studien kartlegger også hva det som er ønskelig og nødvendig av informasjon for at en slik gjennomgang skal være optimal.
Oppgaven tar utgangspunkt i vegprosjektet omregulering av Elgeseter gate i Trondheim kommune. I alt 17 deltakere, med ulik bakgrunn innen vegfaget, deltok i et forsøk hvor hver deltaker enkeltvis skulle utføre en drift og vedlikeholdsgjennomgang av vegprosjektet. Gjennomgangen utføres to ganger, først en gang ved å bruke 2D-tegninger og andre gang ved å bruke en VR-modell. Hver gang det ble nevnt en hindring eller en utfordring knyttet til drift og vedlikehold, ble det notert ned. Hver gjennomgang varte i maks 20 minutter. Etter at gjennomgangene var utført, ble deltakerne bedt om å svare på et evalueringsskjema. Skjemaet, sammen med antall registrerte hindringer eller utfordringer, dannet grunnlaget for videre analyse.
Det ble oppdaget 81,3% flere hindringer og eller utfordringer ved bruk av VR-modell enn ved bruk av 2D-tegningene. Videre analyse av faktorer som arbeidsbakgrunn og erfaring fra drift og vedlikehold understrekte dette. Ved å bruke VR-modell klarte en med 2-5 års erfaring med drift og vedlikehold i snitt å oppdage flere hindringer enn det en med over 20 års erfaring klarte ved hjelp av 2D-tegningene. Uavhengig av om en arbeidet hos en driftsentreprenør, byggherre/konsulent eller i en kommune, var snittet for antall registrerte hindringer omtrent det samme ved bruk VR-modellen. Ved bruk av 2D-tegninger var det derimot et stort sprik mellom driftsentreprenører og de to andre arbeidsgruppene på antall registrerte hindringer.
Svarene fra evalueringsskjemaene forsterket svarene i resultatet. Helhetsinntrykket av det ferdige prosjektet og detaljer som «blir borte» på tegningene gjorde det lettere å oppdage utfordringer knyttet til drift og vedlikehold i VR-modellen. Samtlige deltakere synes bruk av VR-modell for drift og vedlikeholdsgjennomgang kan være nyttig metode å bruke i fremtiden, og ønsket at gjennomgangen skulle utføres minst to ganger i løpet av planprosessen. En gang i reguleringsplanfasen, for å sikre tilstrekkelig areal, og en gang i byggeplanfasen, for å luke vekk dårlige valg som blir detaljert og planlagt.
Ved å se resultatene og svarene fra evalueringsskjemaet i sammenheng er det derfor tydelig at det er betydelig lettere å oppdage potensielle drift og vedlikeholdsutfordringer i VR-modellen enn på 2D-tegningene
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