| 1. |
- Garmabaki, Amir Soleimani, et al.
(författare)
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Underground pipelines and railway infrastructure : failure consequences and restrictions
- 2020
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Ingår i: Structure and Infrastructure Engineering. - : Taylor & Francis. - 1573-2479 .- 1744-8980. ; 16:3, s. 412-430
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Tidskriftsartikel (refereegranskat)abstract
- Underground pipelines are an essential part of the transportation infrastructure. The structural deterioration of pipelines crossing railways and their subsequent failures can entail critical consequences for society and industry, resulting in direct and indirect costs for all the stakeholders involved. Therefore, continuous and accurate condition assessment is critical for the effective management and maintenance of pipeline networks within the transportation infrastructure. The aim of this study has been to identify failure modes and consequences related to pipelines crossing railway corridors. Expert opinions have been collected through interviews and two sets of questionnaires have been distributed to the 291 municipalities in Sweden, with 137 responses in total. The failure analysis has revealed that pipe deformation has the highest impact, followed by pipe rupture at locations where pipelines cross railway infrastructure. For underground pipelines under railway infrastructure, ageing and the external load were awarded a higher ranking than other potential causes of pipeline failure.Authors gratefully acknowledge the funding provided by Sweden’sinnovation agency, Vinnova, through the strategic innovation programmeInfraSweden2030. The funding was granted in a competitiveapplication process that assessed replies to an open call for proposalsconcerning “Condition Assessment and Maintenance of TransportInfrastructure (Grant No. 2016-033113)”.Authors gratefully acknowledge the technical support and collaboration(In-kind support) of Arrsleff R€orteknik at Sweden, Luleå RailwayResearch Center (JVTC), Stormwater&Sewers and the SwedishTransport Administration (Trafikverket). In addition, the authors arethankful to the anonymous referees for their constructive commentsand Dr Matthias Asplund and Dr Masoud Naseri for their support andsuggestions.
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| 2. |
- Sjöstrand, Karin, 1975, et al.
(författare)
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Water supply delivery failures-a scenario-based approach to assess economic losses and risk reduction options
- 2020
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Ingår i: Water (Switzerland). - : MDPI AG. - 2073-4441 .- 2073-4441. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Access to a reliable water supply is central for a well-functioning society. However, water supply systems are subject to a wide range of threats which may affect their ability to provide water to society. This paper presents a novel risk assessment approach that enables thorough analyses of economic losses and associated uncertainties under a range of water supply disruption scenarios. The purpose is to avoid sub-optimization when prioritizing between risk reduction measures, by integrating the full range of possible outcomes from low to high probability events. By combining risk analysis with cost-benefit analysis, additional information is provided on measures for leveraging investments in managing and reducing the risks. This enables the identification of the most economically profitable risk reduction alternatives and enables decision makers to build strategic capacity for operating in difficult and uncertain futures. The presented approach is exemplified on the island of Gotland, one of the most water scarce areas of Sweden.
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| 3. |
- Lindhe, Andreas, 1981, et al.
(författare)
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Dynamic Water Balance Modelling for Risk Assessment and Decision Support on MAR Potential in Botswana
- 2020
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Ingår i: Water (Switzerland). - : MDPI AG. - 2073-4441 .- 2073-4441. ; 12:3, s. 721-13
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Tidskriftsartikel (refereegranskat)abstract
- Botswana experiences a water stressed situation due to the climate and a continuously increasing water demand. Managed Aquifer Recharge (MAR) is considered, among other measures, to improve the situation. To evaluate the possibility for increased water supply security, a probabilistic and dynamic water supply security model was developed. Statistically generated time series of source water availability are used in combination with the dynamic storages in dams and aquifers, and the possible supply is compared with the demand to simulate the magnitude and probability of water supply shortages. The model simulates the system and possible mitigation measures from 2013 to 2035 (23 years), using one-month time steps. The original system is not able to meet the demand, and the estimated volumetric supply reliability in the year 2035 is 0.51. An additional surface water dam (now implemented) will increase the reliability to 0.88 but there will still be a significant water shortage problem. Implementing large-scale MAR can further improve the reliability to at least 0.95. System properties limiting the effect of MAR are identified using the model and show how to further improve the effect of MAR. The case study results illustrate the importance and benefit of using an integrated approach, including time-dependence and future scenarios, when evaluating the need and potential of MAR.
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| 4. |
- Rahmati, O., et al.
(författare)
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Development of novel hybridized models for urban flood susceptibility mapping
- 2020
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Floods in urban environments often result in loss of life and destruction of property, with many negative socio-economic effects. However, the application of most flood prediction models still remains challenging due to data scarcity. This creates a need to develop novel hybridized models based on historical urban flood events, using, e.g., metaheuristic optimization algorithms and wavelet analysis. The hybridized models examined in this study (Wavelet-SVR-Bat and Wavelet-SVR-GWO), designed as intelligent systems, consist of a support vector regression (SVR), integrated with a combination of wavelet transform and metaheuristic optimization algorithms, including the grey wolf optimizer (GWO), and the bat optimizer (Bat). The efficiency of the novel hybridized and standalone SVR models for spatial modeling of urban flood inundation was evaluated using different cutoff-dependent and cutoff-independent evaluation criteria, including area under the receiver operating characteristic curve (AUC), Accuracy (A), Matthews Correlation Coefficient (MCC), Misclassification Rate (MR), and F-score. The results demonstrated that both hybridized models had very high performance (Wavelet-SVR-GWO: AUC = 0.981, A = 0.92, MCC = 0.86, MR = 0.07; Wavelet-SVR-Bat: AUC = 0.972, A = 0.88, MCC = 0.76, MR = 0.11) compared with the standalone SVR (AUC = 0.917, A = 0.85, MCC = 0.7, MR = 0.15). Therefore, these hybridized models are a promising, cost-effective method for spatial modeling of urban flood susceptibility and for providing in-depth insights to guide flood preparedness and emergency response services.
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| 5. |
- Al-Madhlom, Qais, et al.
(författare)
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Potential use of UTES in Babylon Governorate, Iraq
- 2020
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- There is a global attention that the future energy systems will be based on renewable energy like solar and wind. The large-scale utilization of renewables in space heating and cooling requires large Thermal Energy Storage TES to overcome the varying supply and demand. The process of producing the best Underground Thermal Energy Storage UTES system pass through two steps: first, finding the best type of UTES system, second, finding the best locations to install UTES system. Both of these two steps depend extremely on the site specific parameters such that the depth to the groundwater, transmissivity, type of soil, the depth to the bedrock, and seepage velocity. The purpose of this paper is to explain some of the site specific parameters that the type of UTES-system depends on and explain the suitable type of UTES systems. This study considers Babylon province (Iraq) as study area. This province has electricity deficiency due to Heating Ventilating and Air Conditioning HVAC applications. The methodology of this study includes reviewing the literature that consider the study area, and using Arc Map/GIS to visualize some of the in-site parameters. The results indicate that the best type of UTES system for the considered region is either aquifer or pit type, due to the type of the soil and the depth to the crystalline bedrock. The hydraulic conductivity and the seepage velocity in the considered region are (0.0023–2.5) m/d and (1.3 × 10−6 – 3.45 × 10−3) m/d respectively. These conditions satisfy the standards which regard aquifer type.
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| 6. |
- Ezz-Aldeen Mohammad, Mohammad
(författare)
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Sedimentation and Its Challenge for Sustainability of Hydraulic Structures : A Case Study of Mosul Dam Pumping Station
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A successful management and operation of water resources projects are essential to maintain their functions. Dams and reservoirs are one of the largest worldwide infrastructures. They serve one or more functions; reliable store and release of water for different purposes, hydropower generation and flood and draught controls. Sedimentation is one of the serious problems that affects the reservoir`s efficiency; it leads to reduction in storage capacity and reliability for water supply. Furthermore, deposition of sediment near and inside the intakes and hydropower plants cause a negative effect on plant efficiency and corrosion of turbines and pump`s impeller. Generally, degradations of the watersheds, surface runoff and river flow are the main sources and transporters of the reservoir’s sediment. Sediment management techniques are the most economical and efficient approach for sustainability of reservoirs and attached structures. Pumping rate, operation schedule, sub watersheds sediment control and earth dike is the reasonable alternatives that were applied in this study for sediment control and sustain water intakes. In Mosul Dam reservoir, the pumping station is considered as a case study, the station is suffering from sediment accumulation in front and inside the intake. The work includes application of Soil and Water Assessment Tool (SWAT) models to estimate the runoff and sediment load delivered by sub watersheds surrounding the studied area, and a sediment rating curve was considered to assess the sediment load carried by the main river (Tigris River). The Hydrological Engineering Centre’s River Analysis System ( HEC-RAS) model as a one dimensional model (1-D) was applied for sediment routing, and as a two dimensional model (2-D) for flow analysis. This aims to estimate the sediment load deposited in the studied reservoir and evaluated the effects of pumping rate and flow depth on flow velocity distribution, flow stream power and sediment transport. As this study focuses on the sedimentation problem on the area around the intake’s structure and due to compound flow regime and sediment transport near the intakes and withdraws outlets, a three dimensional (3-D) model is considered more suitable than a 1-D or a 2-D model. The Sediment Simulation in Intakes with Multiblock option (SSIIM) model was considered also in this study; a proper control code for studied case was developed. This model depends on Computational Fluid Dynamics (CDF) techniques as a numerical method to solve fluid motion problems.The applied models were calibrated and validated based on measured data of previous studies. The considered statistical criteria indicate that the models’ performances were reasonable for both flow and sediment assessments. The results of all applied strategies show an improvement with a different percent in the amount of sediment deposited in front and inside of the intake, in comparison with the current situation. The optimal improvement was obtained by adding a control earth dike upstream the station. It is considered the most efficient and practical strategy that can be applied for sustainability of the pumping station efficiency and lifespan with fewer dredging requirements.
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| 7. |
- Johansson, Charlotta, et al.
(författare)
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Gåendes singelolyckor
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med detta projekt är att studera på vilka platser det förekommer fallolyckor och singelolyckor med gående, specifikt halkolyckor utomhus, samt vilka förhållanden som leder till halkolyckor utomhus. Studien baseras på STRADA-data från akutsjukhusen i Sunderbyn i Luleå, Gällivare och Skellefteå. Genom att studera var de faktiska olyckorna inträffat, och de förhållanden som rådde på olycksplatsen kan man kartlägga vilka metoder och strategier för halkbekämpning som fungerar mest effektivt; och var de ska tillämpas. I projektet tas även resultat fram för ”black-spot-treatment” för gåendes singelolyckor, dvs. ett resultat för att visa på vilka typer av platser det är särskilt viktigt att halkbekämpa för att minska gåendes singelolyckor.I projektet analyseras olycksstatistik för fotgängare, både vinter – och sommartid med avseende på halka. Väghållare, olycksväg, koordinater och platsbeskrivning används för att sortera in olyckorna i olika stadsdelar i Luleå (Sunderby sjukhus), och Gällivare - Malmberget (Gällivare sjukhus) samt Skellefteå. Dessa är valda att studeras eftersom det är de sjukhus i Norrbotten som samlade in fotgängarolyckor. Arbetet begränsades till att enbart behandla gångytor för fotgängare. Arbetet begränsades dessutom till att enbart studera olyckor som skett de år respektive akutsjukhus har samlat data (Skellefteå sedan 2009, Luleå sedan 2002, och Gällivare 2011), fram till våren år 2017.Vanligaste anledningen till fotgängarolyckan var till 72 % att personen hade halkat, och för dessa var det 98 % som halkade på snö eller is. Det var således minst 70-71 % av alla singelolyckor för gående i de tre orterna som berodde på att det var vintrigt/snöigt/isigt underlag. Dessa andelar är högre än för tidigare studier i Sverige, men är ändå rimliga resultat eftersom det i de tre orterna är längre tidsperiod över året med halkigt underlag p.g.a snö och is än för södra Sverige. Tre typer av platser står för nästan 80 % av alla fallolyckor; gång- och cykelbana (24,0 %), länk på gata (26,9 %) samt fotgängaryta, trottoar (28,1 %). Dessa resultat visar tydligt att det är på allmänt vägtransportområde och på platser som oftast en kommun är väghållare för som stor del av de rapporterade olyckorna sker. Detta utgör svaret på frågan om metod för ”black-spot-treatment” för gåendes singelolyckor; det är där ansträngningar ska ske för att minska antalet olyckor. Resultaten är också en tydlig indikation på det utbredda problemet som gåendes singelolyckor är. Det betyder att det inte finns specifika särskilda platser där ansträngningar ska ske för att öka de gåendes säkerhet i relation för risk för singelolycka. Det finns många ytor, eller typer av platser och ytor, att förbättra och det går således inte att peka ut specifika platser i de tre studerade orterna.Alla tre kommunerna har tydliga principer för både snöröjning och halkbekämpning, och i alla tre orterna är gång- och cykelytor i huvudnät prioriterade, och därefter även centralt belägna trottoarer. En stor del av olyckorna sker dock på den typen av plats. Slutsatsen är således att halkbekämpningen sker på de rätta platserna i stort, men att intensiteten behöver ökas och kanske tiden för åtgärd behöver påskyndas. Det är i detta projekt inte analyserat hur relationen är mellan insatstid för halkbekämpning och tid för när olycka skett. Förslagsvis skulle ett sådant underlag ge en fördjupad kunskap huruvida en förkortad insatstid kunde minska antalet singelolyckor för gående, eller om det kan behövas fler halkbekämpningsåtgärder under en period med halka.
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| 8. |
- Malm, Richard, 1980-, et al.
(författare)
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Lessons Learned Regarding Cracking of a Concrete Arch Dam Due to Seasonal Temperature Variations
- 2020
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Ingår i: Infrastructures. - : MDPI. - 2412-3811. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Dams located in cold areas are subjected to large seasonal temperature variations and many concrete dams have cracked as a result. In the 14th International Commission on Large Dams (ICOLD) Benchmark Workshop, a case study was presented where contributors should predict the cracking and displacements due to seasonal variations. In this paper, the conclusions from this case study are presented. Overall, the results from the contributors are well in line with the observations that can be made on the dam and the measurements performed. This shows that using non-linear numerical models is a suitable tool to accurately predict cracking and estimate the displacements of cracked dams. This case study also highlighted important aspects that need special consideration in order to obtain realistic results that can be used to predict the crack pattern, these being: (1) the importance of performing transient thermal analyses based on robin boundary conditions; (2) the influence of contact formulation between the concrete dam and the foundation; and (3) the use of realistic non-linear material properties. The results and conclusions presented in this paper constitute one important step in achieving best practices to estimate dam safety and better understand the potential failure modes and ageing of concrete dams.
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| 9. |
- Pericault, Youen, 1992-, et al.
(författare)
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Temperature performance of a heat-traced utilidor for sewer and water pipes in seasonally frozen ground
- 2020
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Ingår i: Tunnelling and Underground Space Technology. - : Elsevier. - 0886-7798 .- 1878-4364. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Heat-traced utility corridors (utilidors) can be used in cold regions to install the drinking water and sewer pipes in a shallow trench above the frost depth, thereby limiting excavation needs and the associated economic, social, and environmental costs. Several of these infrastructures were built in the 60s and 70s in Canada, Alaska, Russia, and Norway. More recently, a new type of heat-traced utilidor was built as a pilot project in Kiruna, Sweden to increase the viability of district heating in the area by allowing co-location of all the utility pipes in a shallow trench. Despite several reported cases of undesirably warm drinking water from full-scale projects, previous research efforts on heat-traced utilidors have mainly focused on pipe freeze protection, not on the prevention of excessive temperatures of the drinking water. To ensure comfortable drinking water in terms of taste and smell, an upper temperature limit of 15 °C is usually recommended. The objective of this study was to evaluate the long-term ability of a heat-traced utilidor to maintain sewer temperatures above 0 °C and drinking water temperatures between 0 and 15 °C. Pipe temperatures were measured continuously at two cross sections of a heat-traced utilidor located in Northern Sweden over a period of 22 months. A thermal model, set up and calibrated on the measurements, was used to simulate the impact of extraordinary cold weather conditions on the pipes’ temperatures. The results showed that the utilidor could keep the pipe temperatures within the desired ranges in most cases but that special care should be taken during design to limit drinking water temperatures during the summer.
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| 10. |
- Pettersson, Kaj, 1990, et al.
(författare)
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On the impact of porous media microstructure on rainfall infiltration of thin homogeneous green roof growth substrates
- 2020
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 582
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Tidskriftsartikel (refereegranskat)abstract
- Green roofs are considered an attractive alternative to standard storm water management methods; however one of the primary issues hindering their proliferation is the lack of data regarding their ability to retain and reduce storm water under a variety of climatic conditions. This lack of data is partly due to the complexity of physical processes involved, namely the heterogeneous microscopic behavior that characterize flows in unsaturated porous media. Such an anomalous behavior is difficult to predict a priori, especially in the presence of layered structures. This paper examines water infiltration of a green roof at the pore-scale with the aim to evaluate the effect of the porous microstructure in thin substrate layers. In such layers, the thickness of the medium and the particle size are within the same order of magnitude and the effect of the packing arrangement on the flow dynamics can be pronounced. In this study, three packing arrangements and two different hydraulic heads, analogous to extreme rainfall events typical of Scandinavia, are investigated by means of direct numerical simulations based on the lattice Boltzmann method. The results show that a wider variability of pore sizes in a thin medium can be linked directly to flow pathing preference and consequently less homogenized flow in the primary flow direction. This situation corresponds to intermittent flow behavior at the pore-scale level and reduced macroscopic infiltration rates. This observation unveils the possibility of designing innovative green roof growth substrates: by tuning the particle size and thickness of the layers composing the medium the desired green roof detention time can be attained.
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