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  • 1.
    Aagah, Orod
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Aryannejad, Siavash
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Dynamic analysis of soil-steel composite railway bridges: FE-modeling in Plaxis2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A soil-steel composite bridge is a structure comprised of corrugated steel plates, which are joined with bolted connections, enclosed in friction soil material on both sides and on the top. The surrounding friction soil material, or backfill, is applied in sequential steps, each step involving compaction of the soil, which is a necessity for the construction to accumulate the required bearing capacity. Soil-steel composite bridges are an attractive option as compared with other more customary bridge types, owing to the lower construction time and building cost involved. This is particularly true in cases where gaps in the form of minor watercourses, roads or railways must be bridged.

    The objective of this master thesis is the modelling of an existing soil-steel composite railway bridge in Märsta, Sweden with the finite element software Plaxis. A 3D model is created and calibrated for crown deflection against measurement data collected by the Division of Structural Engineering and Bridges of the Royal Institute of Technology (KTH) in Stockholm, Sweden.

    Once the 3D model is calibrated for deflection, two 2D models with different properties are created in much the same way. In model 1, the full axle load is used and the soil stiffness varied, and in model 2 the soil stiffness acquired in the 3D model is used and the external load varied. The results are compared to measurement data. In 2D model 1 an efficient width of 1,46 m for the soil stiffness is used in combination with the full axle load, and in 2D model 2 an efficient width of 2,85 m is used for the external load, in combination with the soil stiffness acquired in the 3D model.

    Aside from this, parametric studies are performed in order to analyse the effect of certain input parameters upon output results, and in order to analyse influence line lengths.

    Recreating the accelerations and stresses in the existing bridge using finite element models is complicated, and the results reflect this. Below are shown the discrepancies between model results and measurement data for the pipe crown. The scatter in the measurement data has not been taken into consideration for this; these specific numbers are valid only for one particular train passage.

    For crown deflection, the 3D model shows a discrepancy of 4%, 2D model 1 5% and 2D model 2 8% compared with measurement data. For crown acceleration, in the same order, the discrepancy with measurements is 1%, 71% and 21% for maximum acceleration, and 46%, 35% and 28% for minimum acceleration. For maximum crown tensile stress, the discrepancy is 95%, 263% and 13%. For maximum crown compressive stress, the discrepancy is 70%, 16% and 46%.

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  • 2.
    Aagah, Orod
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Kardan, Caesar
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Ett tillgängligt och användarvänligt boende: Anpassningsmöjligheter för människor med rörelsehinder och nedsatt rörelseförmåga2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this paper we have theoretically built a house designed for people with impaired mobility. The

    essay begins with an introduction in which the purpose of the work, the methodology and the

    depth-research part is presented. Then the layout that explains how we intend to adapt the house

    for the demands detailed in the depth-research part is presented. In the same chapter various

    structural components, such as different floors and walls, are specified.

    In the selection of materials we have taken into account the criteria of our specialization and

    adaptation to the aesthetic aspects, where we evaluate materials based upon our wishes regarding

    technique and form. There are also other aspects that are important in the selection of materials,

    including that these are adapted to technical traits of the construction elements and installations.

    In a later chapter the technical installations such as ventilation systems, heating systems,

    electricity and sanitation are presented, where both technical and financial aspects are described

    in detail. The economic aspects are also described in connection with calculating the building's

    power and energy requirements and then presented in the section where costs are accounted for.

    Finally, the work is summarized in the section “Conclusion and Discussion” in which we analyze

    all the work, and based on these analyses conclusions are drawn. During the course of work

    regulations such as Boverkets Byggregler (BBR) and other sources were used. These sources are

    presented in the bibliography section. We also received help and guidance from our supervisors

    in various parts of the work, which we are grateful for.

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  • 3.
    Aalto, Jonatan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Neuman, Elisabeth
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Comparison of Punching Shear Design Provisions for Flat Slabs2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    A new generation of EN 1992-1-1 (2004) also known as Eurocode 2 is under development

    and currently there is a set of proposed provisions regarding section 6.4

    about punching shear, PT1prEN 1992-1-1(2017). It was of interest to compare the

    proposal with the current punching shear design provisions.

    The aim of this master thesis was to compare the punching shear resistance obtained

    in accordance with both design codes. Furthermore the eect of some parameters

    on the resistance was to be compared. It was also of interest to evaluate the userfriendliness

    of the proposal.

    In order to meet the aim, a case study of a real  at slab with drop panels was performed

    together with a parametric study of a pure ctive  at slab. The parametric

    study was performed for inner, edge and corner columns in the cases prestressed,

    without and with shear reinforcement.

    It was concluded that the distance

    av from the column axis to the contra  exural

    location has a big in uence on the punching shear resistance. The factor

    ddg

    considering concrete type and aggregate properties also has a big impact on the resistance.

    The simplied estimation of

    av according to 6.4.3(2) in PT1prEN 1992-1-1

    (2017) may be inaccurate in some cases.

    The length

    b0 of the control perimeter has a larger eect on the resistance in EN

    1992-1-1 (2004) than in PT1prEN 1992-1-1 (2017).

    In PT1prEN 1992-1-1 (2017), studs located outside the second row has no impact

    on the resistance.

    The tensioning force in a prestressed  at slab has a larger in uence on the resistance

    in PT1prEN 1992-1-1 (2017) than in EN 1992-1-1 (2004). Furthermore,

    the reinforcement ratio is increased by the tendons, and thus aect the resistance in

    PT1prEN 1992-1-1 (2017).

    Clearer provisions for the denition of the support strip

    bs for corners and ends

    of walls are needed in PT1prEN 1992-1-1 (2017).

    It may be questionable if the reduction of the perimeter for a large supported area in

    accordance with 6.4.2(4) in PT1prEN 1992-1-1 (2017) underestimates the resistance

    v

    in some cases.

    Considering the work-load with PT1prEN 1992-1-1 (2017), more parameters are

    included. However, they may not require that much eort to obtain.

    Keywords: Punching shear, resistance, concrete,  at slab, design provisions, Eurocode

    2, case study, parametric study, shear reinforcement, prestressed

    vi

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  • 4.
    Aaro, Hedvig
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Restoring the Already Restored2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Restoration has been a tool for enhancing selected parts of history, which tells about the ideals of its time. Today most older buildings have already been through several restorations or renovations. How should one approach and valuate historical layers?

    The purpose of this thesis has been to study earlier restoration work and its approaches and ideals. From this, interventions and design has been done through an alteration of Börshuset in Gamla Stan in Stockholm. The restoration proposal consists of three interventions done with three different approaches: reconstruction, alteration of the existing and an added function and element. Through this method, the project attempts to answer questions about how we can relate to existing buildings, not just as artefacts of their time, but as living things with a complex and layered history. My proposal is a suggestion to reintroduce lost qualities and value the historical layers that are or have been present in Börshuset. By being aware of the difficulty in appreciating newer layers there is a possibility for a better assessment and decision-making that could save historical layers which might become our future cultural heritage.

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  • 5.
    Aas, Steffen
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Hillestad, Thomas
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Verdivurdering av næringseiendom - hva brukes av aktørene i markedet?: - Er det behov for en verdivurderingsstandard i det norske markedet? 2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
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  • 6.
    Aasgaard, Peter Wilhelm Valerius
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    En gate2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Project description:

    Three planned high schools in the area were to have a common building with different social functions, such as a library, social areas and a dining room. 

    Early on in the process, I figured that the program had many functions that potensially could be interesting for the general public, such as a library, social areas and an exhibition. This led to the concept of opening up the building and making it accessible to everyone, creating potensial for an active building, even after school hours. 

    So how can openness be communicated in form? My concept was to extend the public space and let it continue uninterrupted through the whole interior., in short: a ramp. By connecting the ramp to Enskede, lying ten metres above the plot, the building became a public street. Stockholm municipality had an ambition for opening up Slakthusomradet, and the building became a part of this project.

    The program in the assignment excisted of many zones, usually associated with staff areas. I wanted to change that conception and make these rooms open to the public. These rooms included for example administration, cleaning and kitchen. 

    The materials used were all taken from typical public spaces, such as concrete, stone, asphalt, steel and glass. Furthermore, the character of the materials were to change when you moved from “the street” and into the closed spaces. Here you would find wooden walls and furniture, as well as curtains of cotton.

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  • 7.
    Aassi, Adil
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Drift och underhåll för högre effektivitet av järnvägar.2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Den senaste svenska vintern var en riktig katastrof som bestod av Ovanliga mängder snö, fukt och kyla, från mitten av december 2009 till mitten av mars 2010. Snömassor orsakade stora problem i tågtrafiken, både nationellt och lokalt. Det påverkade både gods- och persontransporten. Halka och tak ras ledde till personskador och dödsolyckor. Kylan påverkade även elnät som ledde till att människor stod utan värme och belysning. Allmänheten drabbades av snöovädret på olika sätt. Människor skadades i trafiken, halkolyckor, och flera tak som rasade ner. Människor kom även försent till olika destinationer. I södra och mellersta Sverige var problemet störst inom området transport (väg, järnväg). Störningar i vatten, elförsörjningen och tak ras. I söder uppstod ett kontaktledningsfel med flera växel- och signalproblem.

    En viktig sak är att det inte går att tänka att den vintern bara var en engångsföreteelse, utan Trafikverket måste tänka på att Sverige ligger i Norden och att vintern 2009/10 kan upprepas flera gånger. Därför är det viktigt att bygga en modell för underhållet. Trafikverket skulle kunna ta de sista vintrarna på allvar och ta fram en åtgärdsplan för att minska effekterna av framtida, svåra vinterförhållanden.

    Avhjälpande åtgärder måste då sättas in snabbt för att förhindra störningar i trafiken. Mången tågtrafik störningar beror på fel i någon eller några komponenter som själva baninfrastrukturen består av. En jämförelse har gjorts mellan spårväxlar under sommaren och spårväxlar under vintrar, som visar 85 % fler fel under vintertid än sommartid. Trafikverkets kostnader för underhåll av järnvägar på lång sikt uppgår till 4 miljarder. Regeringen fastställde den nya nationella trafikplanen för utveckling av transportsystemet för perioden 2010-2021 i slutet av mars 2010. I arbetet undersöks en jämförelse, så kallad "Benchmarking" mellan Sverige och Schweiz som visar hög kvalitet i kapacitetsutnyttjande och hög punktlighet i Schweiz. Punktlighet i Schweiz har stigit 97 % medan i Sverige var 87 %.

    Ett övergripande syfte med arbetet är att undersöka hur effektiviteten på det svenska järnvägs nätet kan förbättras genom att studera framgångarna i Schweiz.

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  • 8.
    Abadii, Eyerusalem
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Wastewater Treatment by Partial Nitritation / Anammox -Hydroxyapatite coupled process (PN/A-HAP)2024Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nitrogen and phosphorus pollution is still a serious environmental problem and a major threat to sustainable development, as they mainly cause eutrophication. Therefore, increasingly stricter requirements are placed on wastewater treatment plants when it comes to emissions of nutrients. To meet these requirements, it is important to continuously renew and improve the purification processes, thereby reducing the emissions of nutrients to the sea, lakes, and streams. The effect of simultaneous nitrogen removal and phosphorus recycling was investigated in this study, employing a one-step process for partial nitritation/anammox-hydroxyapatite (PN/HAP). An experiment in a laboratory-scale SBR reactor (Sequence Batch Reactor) was performed using wastewater from the side-stream centrate. This study validated results to a certain extent published studies by other researchers. However, they had almost exclusively used synthetic wastewater, unlike the here presented where real wastewater was used. The innovative PN/A-HAP process showed effective nitrogen and phosphorus removal without additional aeration or pH adjustment, which means lower energy consumption, reduced nitrous oxide emissions, and reduced sludge production. The results showed an average nitrogen removal efficiency of 32.84% and an average phosphorus removal efficiency of 71.48%. These results indicate significant potential for sustainable wastewater management for some nitrogen and phosphorus side streams at the treatment plants. However, further research is required on a larger scale to precisely assess the long-term separation efficiency for nitrogen and phosphorus, as well as the scalability and usability of the process under real conditions. 

    This Thesis was performed in the frame of a research project 'Process development of CA-induced HAP (Hydroxyapatite) granulation in nitrogen separation with Anammox' funded by the VA Cluster Mälardalen. 

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  • 9.
    Abaid, Mohammed
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Land and Water Resources Engineering.
    Evaluation of Jatropha Curcas as future en-ergy crop in some African countries.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biofuels now days consider as one of the successful alternative to meet the challenges associated with climate change and peak oil, as well as a way for poorer countries to develop an industry in order to enhance social and economic development. In many developing countries and particularly in Africa, this has led to large-scale investments in lands by foreign companies, and as a consequence there has been a debate on whether these actions are environmentally sustainable and whether this kind of activity actually brings economic development. The investments of biofuels in Africa, espe-cially the Jatropha plantations are debatable. Several arguments have been concentrat-ed on development goals, economic issues and environmental concerns. This report evaluates the status of some Jatropha projects in Sudan, Ethiopia, Kenya and Tanza-nia, the outcomes of the report show that biofuels from Jatropha lead to a significant socio -economic benefits by creating many jobs opportunities and improve the stand-ard of living in Africa. However, inadequate funding’s, high investment costs, no clear policies for biodiesel are the most challenging for Jatropha in Africa which need fur-ther mechanisms and ideology by African scientists, leaders, NGOs, farmers and deci-sion makers. In the studied countries, it was reported that the Jatropha produce low yields of oil seeds especially in the marginal lands with no enough water supplies. In Kenya the productivity of Jatropha is very low for large scale- project. Moreover some social and environmental impacts are also seen for Jatropha cultivations in Ethiopia, Kenya and Tanzania. Some Jatropha projects have impacted the food security nega-tively; nevertheless some biofuels experts believe that Jatropha has no any adverse im-pacts on food security since it is inedible and grown on marginal lands. In Ethiopia, the main environmental impacts of Jatropha are related to biodiversity, water quality and quantity. In Kenya, the environmental impacts are related to biodiversity, carbon emissions, water withdrawal, pollution of agro- chemicals usage, deforestation and soil erosion, whereas in Tanzania, the main environmental issues are connected to the change of land use system, impacts on biodiversity and impacts on water resources.

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  • 10. Abarca, R. R. M.
    et al.
    Gaudio, M. T.
    Chakraborty, S.
    Bhattacharya, Prosun
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Water and Environmental Engineering.
    Metals toxic pollutants in the environment: Anthropogenic and geological causes and remediation2019In: Current Trends and Future Developments on (Bio-) Membranes: Membranes in Environmental Applications, Elsevier Inc. , 2019, p. 109-124Chapter in book (Other academic)
    Abstract [en]

    Heavy metals are naturally present in nature, but if their concentration is higher than the normal accepted threshold levels, they constitute one of the pollutants that is more difficult to remove and also to rehabilitate the contaminated site by them. There are many heavy-metal pollutants-the most common among them are arsenic (As), chromium (Cr), lead (Pb), mercury (Hg), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), and zinc (Zn), along with the less common ones, which produced, for example, by the nuclear process, such as uranium (U)-in different configuration; hence, many possibilities of contamination in the world exist, and they are more difficult to remove.Thus heavy-metal pollution is more and more becoming one of the principal issues of the global interest, because it is common to both industrialized countries and developing countries. These issues are getting hard to be recognized and cannot be followed the simple rules concerning safety and environmental protection, thus fall into the same errors of the already industrialized countries. At the same time, new environment-remediation techniques are developed in the last decade, especially, in these last years. Some of these technologies concern physical or chemical process or effects, such as ion exchanges, flotations, and photocatalysis, while other technologies concern the use of membrane process, especially ultrafiltration or membrane integrated process or hybrid systems, where membranes are generally submerged and used together with another process.In this chapter a review of this problem and some example of technologies for removing and remediation of the environment are reported. 

  • 11.
    Abaris, Nedas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Sjönoce, Firass
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Investors and valuers: Similarities and differences from a behavioural perspective2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is an explorative analysis of the commercial real estate actors. The behavioral theory has revealed many flaws in the neo classical assumptions. This includes models of rationality and prescribed behaviors. Research suggests both appraisers and investor act in ways that can be seen as irrational. Appraisers amongst other things anchor to figures that are not part of the valuation theory and investor invest on bases that are not fundamentally sound. Both also exhibit biases, such as confirmation bias and loss aversion. If valuation does not reflect the way market participants behave then they fail to give us a correct market value. We use interviews to try and understand how appraisers try to reflect the market and to understand how investors and other market actors value properties by comparing their use of the DCF-method. Our results suggest that there are many technical differences between how methods are used by different actors and that appraisers have a too close connection with the market actors.

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  • 12.
    Abascal, Angela
    et al.
    Univ Navarra, Sch Architecture, Pamplona, Spain.;Univ Navarra, Navarra Ctr Int Dev, Pamplona, Spain..
    Rodriguez-Carreno, Ignacio
    Univ Navarra, Fac Econ, Pamplona, Spain.;Univ Navarra, Data Sci & Artificial Intelligence Inst, Pamplona, Spain..
    Vanhuysse, Sabine
    Univ libre Bruxelles ULB, Dept Geosci Environm & Soc, Brussels, Belgium..
    Georganos, Stefanos
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geoinformatics.
    Sliuzas, Richard
    Univ Twente, Fac Geoinformat Sci & Earth Observat, Enschede, Netherlands..
    Wolff, Eleonore
    Univ libre Bruxelles ULB, Dept Geosci Environm & Soc, Brussels, Belgium..
    Kuffer, Monika
    Univ Twente, Fac Geoinformat Sci & Earth Observat, Enschede, Netherlands..
    Identifying degrees of deprivation from space using deep learning and morphological spatial analysis of deprived urban areas2022In: Computers, Environment and Urban Systems, ISSN 0198-9715, E-ISSN 1873-7587, Vol. 95, article id 101820Article in journal (Refereed)
    Abstract [en]

    Many cities in low- and medium-income countries (LMICs) are facing rapid unplanned growth of built-up areas, while detailed information on these deprived urban areas (DUAs) is lacking. There exist visible differences in housing conditions and urban spaces, and these differences are linked to urban deprivation. However, the appropriate geospatial information for unravelling urban deprivation is typically not available for DUAs in LMICs, constituting an urgent knowledge gap. The objective of this study is to apply deep learning techniques and morphological analysis to identify degrees of deprivation in DUAs. To this end, we first generate a reference dataset of building footprints using a participatory community-based crowd-sourcing approach. Secondly, we adapt a deep learning model based on the U-Net architecture for the semantic segmentation of satellite imagery (WorldView 3) to generate building footprints. Lastly, we compute multi-level morphological features from building footprints for identifying the deprivation variation within DUAs. Our results show that deep learning techniques perform satisfactorily for predicting building footprints in DUAs, yielding an accuracy of F1 score = 0.84 and Jaccard Index = 0.73. The resulting building footprints (predicted buildings) are useful for the computation of morphology metrics at the grid cell level, as, in high-density areas, buildings cannot be detected individually but in clumps. Morphological features capture physical differences of deprivation within DUAs. Four indicators are used to define the morphology in DUAs, i.e., two related to building form (building size and inner irregularity) and two covering the form of open spaces (proximity and directionality). The degree of deprivation can be evaluated from the analysis of morphological features extracted from the predicted buildings, resulting in three categories: high, medium, and low deprivation. The outcome of this study contributes to the advancement of methods for producing up-to-date and disaggregated morphological spatial data on urban DUAs (often referred to as 'slums') which are essential for understanding the physical dimensions of deprivation, and hence planning targeted interventions accordingly.

  • 13. Abate, M.
    et al.
    De Jong, Gerard
    KTH, School of Architecture and the Built Environment (ABE), Centres, Centre for Transport Studies, CTS.
    The optimal shipment size and truck size choice - The allocation of trucks across hauls2014In: Transportation Research Part A: Policy and Practice, ISSN 0965-8564, E-ISSN 1879-2375, Vol. 59, p. 262-277Article in journal (Refereed)
    Abstract [en]

    There has been a growing interest in understanding how firms allocate their trucks across hauls, and how this allocation changes under various economic environments. This study investigates how variations in route/haul, carrier and vehicle characteristics affect the optimal vehicle size choice and the associated choice of shipment size. We show that the two choices are derived from the same optimization problem. There can be a continuum of shipment sizes, but decision-makers in freight transport have to choose from a limited number of vehicle alternatives. Therefore, we use a discrete-continuous econometric model where shipment size is modeled as a continuous variable, and vehicle size/type choice as a discrete variable. The results indicate that when faced with higher demand, and during longer trips firms are more likely to use heavier vehicles and ship in larger quantities which suggest that firms are realizing economies of scale and economies of distance. The study also discusses the effect of vehicle operating cost on the vehicle selection process and its policy implications.

  • 14.
    Abayneh Alembo, Zinash
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    User delay costs and uncertainty in the traffic forecast for road projects.2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are experimental based software packages as well as traffic simulation models that

    are used for analyzing life cycle cost of road projects. Among those our study was focused on

    currently available models to analyze the road user delay costs and to identify factors

    affecting road user delay costs. Sensitivity analyses were performed to identify the important

    factors that influence the user delay cost. Finally, prediction of future traffic demand as well

    as user delay cost, using the binomial lattice model, were presented to include the uncertainty

    of future traffic and user delay costs. The results of this study could help the highway

    designers with evaluating the future traffic.

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  • 15. Abbak, Ramazan A.
    et al.
    Sjöberg, Lars E.
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Ellmann, Artu
    Ustun, Aydin
    A precise gravimetric geoid model in a mountainous area with scarce gravity data: a case study in central Turkey2012In: Studia Geophysica et Geodaetica, ISSN 0039-3169, E-ISSN 1573-1626, Vol. 56, no 4, p. 909-927Article in journal (Refereed)
    Abstract [en]

    In mountainous regions with scarce gravity data, gravimetric geoid determination is a difficult task that needs special attention to obtain reliable results satisfying the demands, e.g., of engineering applications. The present study investigates a procedure for combining a suitable global geopotential model and available terrestrial data in order to obtain a precise regional geoid model for Konya Closed Basin (KCB). The KCB is located in the central part of Turkey, where a very limited amount of terrestrial gravity data is available. Various data sources, such as the Turkish digital elevation model with 3 '' x 3 '' resolution, a recently published satellite-only global geopotential model from the Gravity Recovery and Climate Experiment satellite (GRACE) and the ground gravity observations, are combined in the least-squares sense by the modified Stokes' formula. The new gravimetric geoid model is compared with Global Positioning System (GPS)/levelling at the control points, resulting in the Root Mean Square Error (RMS) differences of +/- 6.4 cm and 1.7 ppm in the absolute and relative senses, respectively. This regional geoid model appears to he more accurate than the Earth Gravitational Model 2008, which is the best global model over the target area, with the RMS differences of +/- 8.6 cm and 1.8 ppm in the absolute and relative senses, respectively. These results show that the accuracy of a regional gravimetric model can be augmented by the combination of a global geopotential model and local terrestrial data in mountainous areas even though the quality and resolution of the primary terrestrial data are not satisfactory to the geoid modelling procedure.

  • 16.
    Abbas, Qaalid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hussein, Abdiwahab
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Studie om framtagning av montageplaner: En granskning av monteringsprocessen för prefabricerat byggande2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Dagens industrier anpassar numera sin tillverkning för att kunna massproducera och dra ner på personal och kostnader. Detta innebär ökad automatisering med större och kraftigare maskiner, utrustning och verktyg. För att garantera säkerheten på arbetsplatsen är det därför viktigt att rätt skyddsanordning och myndighetskrav följs och används. I byggbranschen ställer arbetsmiljöverket krav på branschföretagen gällande arbetsmiljö och särskilda underlag för produktionsarbetet. Denna studie undersöker montageplanen som används vid industriellt byggande som innebär användning av tunga, prefabricerade, element vid husbyggnad.

    Syftet är att studera hur en montageplan planeras, upprättas och implementeras. Studien utförs på uppdrag av In3prenör och omfattar 10 veckors arbete. Författarna har tillhandahållits information kring montageplanen för två projekt som studerats jämsides. Det ena, ett pågående projekt, är Allégården som är ett ROT-projekt av ett vård- och omsorgsboende och det andra, projekt Arlanda, är en nybyggnation av en servicebyggnad. Metoder som använts för att uppnå resultatet har varit en kombination av litteraturstudier, granskning av montageplaner, platsbesök och intervjuer.

    Resultatet visar på att otydliga riktlinjer kring vad som ska inkluderas i montageplanen är det största skälet till att det blir fel på arbetsplatsen. Det har även från intervjuerna påpekats att på grund av den tidspressade situationen och målbilden att undgå förseningar kan det ske misstag som kan få allvarliga konsekvenser. För att förbättra kvaliteten i montageplanerna måste riktlinjer från arbetsmiljöverket och boverket bli tydligare gällande montageplanens innehåll. Det är också viktigt att kritiska moment som kan medföra ökade risker framgår i montageplanen, vidare kan montörer utbildas för att öka deras riskmedvetenhet.

  • 17.
    Abbasi, Mazhar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Dawit Ghebreigziabher, Kibret
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Objektklassificerad modellering och effektivisering avmängduttag2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The lack of fluent communication in the building industry has caught people’s attention because of

    time-based costs appearing in 2D and 3D modelling and takeoffs. These costs emerge in construction

    when miscommunication takes place between professionals in different projects.

    A research study of the subject has revealed the reason behind the current days’ miscommunication

    issues. The study shows that although the professionals tend to have an efficient way of working, the

    result isn’t very beneficial for the next man. Therefore a conclusion of the issue creates a demand for a

    mutual language in modelling and better softwares for takeoffs.

    This report’s results, with regards to optimization of modeling, has brought to light the use for the

    objectclassificationsystem BIP. These BIP-codes are used for branding objects in models of which the

    branding consists of unique codes. The code of every individual object has the purpose of being

    recognized by every project member and remain the same throughout the project.

    The proposal for the optimization of takeoffs is a software called VICO Office. The software contains

    well-advised methods for the import of models and close to automated takeoffs of these models.

    In conclusion, the study implies that there is sufficient motive to question the old ways of working and

    that light should be shed on new approaches. Technology and the industry face a constant change and

    the efficiency of current methods are never far away.

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  • 18.
    Abbasi, Mozaffer
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Analys och implementering av VSL-System i FEM-Design för kontroll av stabiliserande effekt: En undersökning i syfte att fastlägga effekten av VSL-kablar i FEM-Design för att utvärdera dess stabiliserande påverkan.2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
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  • 19.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A pin-on-disc study of the rate of airborne wear particle emissions from railway braking materials2012In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 284, p. 18-29Article in journal (Refereed)
    Abstract [en]

    The current study investigates the characteristics of particles generated from the wear of braking materials, and provides an applicable index for measuring and comparing wear particle emissions. A pin-on-disc tribometer equipped with particle measurement instruments was used. The number concentration, size, morphology, and mass concentration of generated particles were investigated and reported for particles 10 nm-32 mu m in diameter. The particles were also collected on filters and investigated using EDS and SEM. The effects of wear mechanisms on particle morphology and changes in particle concentration are discussed. A new index, the airborne wear particle emission rate (AWPER), is suggested that could be used in legislation to control non-exhaust emissions from transport modes, particularly rail transport.

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  • 20.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Jansson, Anders
    Stockholm University, Applied Environmental Science, Stockholm, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A field test study of airborne wear particles from a running regional train2012In: IMechE, Part F: Journal of Rail and Rapid Transit, ISSN 0954-4097, Vol. 226, no 1, p. 95-109Article in journal (Refereed)
    Abstract [en]

    Inhalable airborne particles have inverse health affect. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up.

    Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280 nm, 350 nm, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 μm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280 nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. FESEM images captured particles sizing down to 50 nm. The ICP-MS results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

     

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  • 21.
    Abbasi, Saeed
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Larsson, Christina
    Bombardier Transportation Sweden AB, Västerås, Sweden.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A study of airborne wear particles generated from organic railway brake pads and brake discs2011In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 273, no 1, p. 93-99Article in journal (Refereed)
    Abstract [en]

    Brake pads on wheel-mounted disc brakes are often used in rail transport due to their good thermal properties and robustness. During braking, both the disc and the pads are worn. This wear process generates particles that may become airborne and thus affect human health. The long term purpose of ‘Airborne particles in Rail transport’ project is to gain knowledge on the wear mechanisms in order to find means of controlling the number and size distribution of airborne particles. In this regard, a series of full-scale field tests and laboratory tests with a pin-on-disc machine have been conducted. The morphology and the matter of particles, along with their size distribution and concentration, have been studied. The validity of results from the pin-on-disc simulation has been verified by the field test results. Results show an ultra-fine peak for particles with a diameter size around 100 nm in diameter, a dominant fine peak for particles with a size of around 350 nm in diameter, and a coarse peak with a size of 3-7 μm in diameter. Materials such as iron, copper, aluminium, chromium, cobalt, antimony, and zinc have been detected in the nano-sized particles.

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  • 22.
    Abbasiverki, Roghayeh
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Analysis of underground concrete pipelines subjected to seismic high-frequency loads2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Buried pipelines are tubular structures that are used for transportation of important liquid materials and gas in order to provide safety for human life. During an earthquake, imposed loads from soil deformations on concrete pipelines may cause severe damages, possibly causing disturbance in vital systems, such as cooling of nuclear power facilities. The high level of safety has caused a demand for reliable seismic analyses, also for structures built in the regions that have not traditionally been considered as highly seismically active. The focus in this study is on areas with seismic and geological conditions corresponding to those in Sweden and Northern Europe. Earthquakes in Sweden for regions with hard rock dominated by high-frequency ground vibrations, Propagation of such high-frequency waves through the rock mass and soil medium affect underground structures such as pipelines.

    The aim of this project is investigating parameters that affect response of buried pipelines due to high-frequency seismic excitations. The main focus of the study is on reinforced concrete pipelines. Steel pipelines are also studied for comparison purposes. The effects of water mass, burial depth, soil layer thickness and non-uniform ground thickness caused by inclined bedrock are studied. The results are compared to those obtained for low-frequency earthquakes and the relationship between strong ground motion parameters and pipelines response is investigated. It is shown that, especially for high frequency earthquake excitations, non-uniform ground thickness due to inclined bedrock significantly increase stresses in the pipelines. For the conditions studied, it is clear that high-frequency seismic excitation is less likely to cause damage to buried concrete pipelines. However, the main conclusion is that seismic analysis is motivated also for pipelines in high-frequency earthquake areas since local variation in the ground conditions can have a significant effect on the safety.

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  • 23.
    Abbasiverki, Roghayeh
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Initial study on seismic analyses of concrete and embankment dams in Sweden2017Report (Other academic)
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  • 24.
    Abbasiverki, Roghayeh
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Numerical modelling considerations for analysis of concrete hydraulic structures subjected to high-frequency seismic loads2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Concrete hydraulic structures are of great importance in today's society. When situated in areas with hard bedrock, these structures may become extra vulnerable to seismic excitations as these here are dominated by high-frequency vibrations which can have disastrous consequences for slender structures. The aim of this thesis was to investigate special considerations that must be made when conducting analyses of such hydraulic structures during high-frequency excitations. Underground and on the ground structures were investigated separately. Underground concrete pipelines and concrete buttress dams were selected for the study because their behaviour when exposed to seismic excitations is dominated by their stiffness. The most effective models and modelling methods for the seismic analyses of such structures were implemented and evaluated. Two-dimensional finite element (FE) models were developed for the dynamic analysis of underground concrete pipelines loaded by seismic waves propagating from bedrock through soil. The interaction between the bedrock and the surrounding soil was investigated with respect to rock geometry and soil properties. The surface of dam foundations is commonly irregular, resulting in nonuniform motions at the dam-foundation interface. The free-field modelling methods for concrete dam foundations were adapted in order to accurately describe the propagation of earthquake vibrations from the source to the ground surface. The implementation of a threedimensional FE model for concrete buttress dams was investigated. Two different methods for free-field modelling are presented, which can be implemented independently of the software used. The seismic loads are applied as effective earthquake forces at non-reflecting boundaries. In the first method, the free-field motions at the non-reflecting boundaries are determined by the so-called domain reduction method using the direct FE calculation. In the second method, the free-field motions are analytically determined based on the onedimensional wave propagation theory. The results are also compared with the massless foundation modelling approach, in which the topographical amplifications are neglected. It was demonstrated that a two-dimensional model can effectively account for pipeline behaviour. The most important aspect of the models is the ability to capture bending deformations, as segmented structures such as pipelines are vulnerable in this respect. Nonuniform bedrock reduces the safety of concrete pipeline, especially because of bending deformations in the pipe and joints. The massless method gave unreliable results for analyses of dams, especially for high-frequency excitations. The analytical method was also unreliable in estimating the non-linear behaviour of the dams. But, a new time domain deconvolution method was developed to transform the earthquake motion from the foundation surface to the corresponding input motion at depth. It wasfound that free-field modelling of foundations using the direct FE method can accurately capture the topographic amplifications of the seismic excitations. It was shown that a three-dimensional model is required for seismic evaluation of concrete buttress dams. The topographic amplification of high-frequency waves at the surface of canyons had a significant effect on the response of this type of dam. 

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  • 25.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ahmed, Lamis
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Nordström, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures. Sweco.
    Analysis of load and response on large hydropower draft tube structures2019Report (Refereed)
    Abstract [en]

    In a reaction turbine, the runner outlet is connected to a diffuser which is called the draft tube. Large hydropower units with large effect and large discharge normally require large dimensions on the waterways. In some large-scale facilities, the total width of the draft tube is so large there is a need for a supporting centre wall in the draft tube. In the Swedish hydropower business, there are several cases where damages or cracks have been reported in the contact between the roof and the supporting centre wall. The most likely reason for cracking between wall and roof is when refilling the draft tube after it has been drained for inspection. A too quick refilling will give an upwards lifting force on the roof that can be larger than the capacity in the joint. There are still uncertainties regarding the risk for a long-term scenario where any operational pattern could give continued crack propagation.

    Vattenfall Hydropower has made an installation with pressure and strain sensors in one of their facilities with a centre wall supported draft tube and a cavity between the roof and the rock cavern. The aim of the project is to get a better understanding on the behaviour of the roof and centre wall during different operational events by evaluating measurements from the draft tube and investigating possible load cases that can create continued crack propagation during operation. In this regard, in this project, the measurements are analysed to discover the different operational patterns and the corresponding effect on applied pressure on draft tube central wall and roof and structure response. A simplified finite element model of the draft tube is demonstrated and the response from the structure due to extracted load patterns is compared with the measurements.

    One-year measurements of the unit operation indicated that unit operates over the whole range with many start/stops. Three major types of operation were: normal operation (working in daytime and downtime at night), continuous operation with no stop and start-stop events with sharp start/stop in the morning and afternoon. The analysis of pressure measurements indicated that the fluid motion in the straight diffuser is turbulent and possibly influenced by vortex formation under the runner. Therefore, the pressure on the right side of the central wall was higher than on the left side.

    The quality of the strain measurements showed to be of insufficient quality and lack of information regarding the set-up. This has given questions on the possibility to get reliable results in the evaluation. Nevertheless, an evaluation has been performed. The evaluation of strain measurements demonstrated higher strain values at the upstream side of the central wall and roof. Moreover, the strain on underside of the roof was higher than on the central wall. Sudden fluctuation during continuous operation and sequence of start/stop were the cases that in long-term may cause damage to the structure due to fatigue problems. The results from finite element model indicated high tensile strength at the upstream side of the straight diffuser, in contact between the roof and the central wall where a crack has been detected in the real structure.

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  • 26.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Analysis of buried reinforced concrete pipelines subjected to seismic waves2014Conference paper (Refereed)
  • 27.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Seismic response of large diameter buried concrete pipelines subjected to high frequency earthquake excitations2020In: Int. J. Structural Engineering, ISSN 1758-7328, Vol. 10, no 4, p. 307-329Article in journal (Refereed)
    Abstract [en]

    Buried pipelines are tubular structures that cross large areas with different geological conditions. During an earthquake, imposed loads from soil deformations on pipelines may cause drastic damages. In this study two dimensional finite element models of pipelines and surrounding soils are usedfor simulation of seismic waves that propagate from the bedrock through thesoil. The models describe both longitudinal and transverse cross-sections ofpipelines and the soil-pipe interaction is described as a nonlinear behaviour.The effects of uniform ground with different burial depth and soil layer thickness, soil stiffness and non-uniform ground on the seismic response of reinforced concrete pipelines is studied. Two earthquakes, with high and low frequency contents, are employed for the dynamic analysis. The results show asignificant effect on the response due to non-uniform ground caused by inclined bedrock, especially for high frequency earthquake excitations.

  • 28.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Seismic response of buried concrete pipelines subjected to highfrequency earthquakesIn: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529Article in journal (Refereed)
    Abstract [en]

    Buried pipelines are tubular structures that cross large areas with different geological conditions. During an earthquake, imposed loads from soil deformations on concrete pipelines may cause severe damages. In this study, the use of two-dimensional finite element models of pipelines and surrounding soil for simulation of seismic waves that propagate from the bedrock through the soil are demonstrated. The models describe both longitudinal and transverse cross-sections of pipelines and the soil-pipe interaction is modelled as a nonlinear behaviour. The effects of uniform ground with different burial depths, soil layer thickness, soil stiffness and bedrock geometry on the seismic response of reinforced concrete pipelines is studied. Two earthquakes, with high and low frequency contents, are employed for the dynamic analysis. The results show that there is a much smaller risk of damage from high-frequency earthquakes, but that there is a significant effect on the response due to possible irregular ground with inclined bedrock.

  • 29.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Malm, Richard
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Analysis of shallowly buried reinforced concrete pipelines subjected to earthquake loads2014In: Nordic Concrete Research, ISSN 0800-6377, no 51, p. 111-130Article in journal (Refereed)
    Abstract [en]

    Buried reinforced concrete pipelines are widelyused in e.g. water and wastewater systems. Failure of these infrastructures mayresult in drastic effects and recently they have been brought into focus asvital components in safety systems for nuclear power installations. The highlevel of safety has here lead to a demand for reliable earthquake risk analyses.In this paper, methods are compared and the use of seismic design loadsdemonstrated. FE analysis in 2D of soil-pipe interaction under seismic wavepropagation is performed. The performance of concrete pipes subjected toseismic waves with different frequency content is evaluated with respect todifferent soil condition but also water mass effect.

  • 30.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Malm, Richard
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Implementation of free-field modelling of foundations for large dam structures exposed to high-frequency vibrationsIn: Article in journal (Refereed)
  • 31.
    Abbasiverki, Roghayeh
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Malm, Richard
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Ansell, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Nordström, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Nonlinear Behaviour of Concrete Buttress Dams under High-Frequency Excitations Taking into Account Topographical Amplifications2021In: Shock and Vibration, ISSN 1070-9622, E-ISSN 1875-9203, Vol. 2021, p. 1-22Article in journal (Refereed)
    Abstract [en]

    Concrete buttress dams could potentially be susceptible to high-frequency vibrations, especially in the cross-stream direction, due to their slender design. Previous studies have mainly focused on low-frequency vibrations in stream direction using a simplified foundation model with the massless method, which does not consider topographic amplifications. This paper therefore investigates the nonlinear behaviour of concrete buttress dams subjected to high-frequency excitations, considering cross-stream vibrations. For comparison, the effect of low-frequency excitations is also investigated. The influence of the irregular topography of the foundation surface on the amplification of seismic waves at the foundation surface and thus in the dam is considered by a rigorous method based on the domain-reduction method using the direct finite element method. The sensitivity of the calculated response of the dam to the free-field modelling approach is investigated by comparing the result with analyses using an analytical method based on one-dimensional wave propagation theory and a massless approach. Available deconvolution software is based on the one-dimensional shear wave propagation to transform the earthquake motion from the foundation surface to the corresponding input motion at depth. Here, a new deconvolution method for both shear and pressure wave propagation is developed based on an iterative time-domain procedure using a one-dimensional finite element column. The examples presented showed that topographic amplifications of high-frequency excitations have a significant impact on the response of this type of dam. Cross-stream vibrations reduced the safety of the dam due to the opening of the joints and the increasing stresses. The foundation modelling approach had a significant impact on the calculated response of the dam. The massless method produced unreliable results, especially for high-frequency excitations. The free-field modelling with the analytical method led to unreliable joint openings. It is therefore recommended to use an accurate approach for foundation modelling, especially in cases where nonlinearity is considered.

  • 32. Abbaszadeh Shahri, A.
    et al.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Renkel, C.
    Artificial intelligence models to generate visualized bedrock level: a case study in Sweden2020In: Modeling Earth Systems and Environment, ISSN 2363-6203, E-ISSN 2363-6211, Vol. 6, no 3, p. 1509-1528Article in journal (Refereed)
    Abstract [en]

    Assessment of the spatial distribution of bedrock level (BL) as the lower boundary of soil layers is associated with many uncertainties. Increasing our knowledge about the spatial variability of BL through high resolution and more accurate predictive models is an important challenge for the design of safe and economical geostructures. In this paper, the efficiency and predictability of different artificial intelligence (AI)-based models in generating improved 3D spatial distributions of the BL for an area in Stockholm, Sweden, were explored. Multilayer percepterons, generalized feed-forward neural network (GFFN), radial based function, and support vector regression (SVR) were developed and compared to ordinary kriging geostatistical technique. Analysis of the improvement in progress using confusion matrixes showed that the GFFN and SVR provided closer results to realities. The ranking of performance accuracy using different statistical errors and precision/recall curves also demonstrated the superiority and robustness of the GFFN and SVR compared to the other models. The results indicated that in the absence of measured data the AI models are flexible and efficient tools in creating more accurate spatial 3D models. Analyses of confidence intervals and prediction intervals confirmed that the developed AI models can overcome the associated uncertainties and provide appropriate prediction at any point in the subsurface of the study area. 

  • 33. Abbaszadeh Shahri, A.
    et al.
    Shan, Chunling
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    A Novel Approach to Uncertainty Quantification in Groundwater Table Modeling by Automated Predictive Deep Learning2022In: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981, Vol. 31, no 3, p. 1351-1373Article in journal (Refereed)
    Abstract [en]

    Uncertainty quantification (UQ) is an important benchmark to assess the performance of artificial intelligence (AI) and particularly deep learning ensembled-based models. However, the ability for UQ using current AI-based methods is not only limited in terms of computational resources but it also requires changes to topology and optimization processes, as well as multiple performances to monitor model instabilities. From both geo-engineering and societal perspectives, a predictive groundwater table (GWT) model presents an important challenge, where a lack of UQ limits the validity of findings and may undermine science-based decisions. To overcome and address these limitations, a novel ensemble, an automated random deactivating connective weights approach (ARDCW), is presented and applied to retrieved geographical locations of GWT data from a geo-engineering project in Stockholm, Sweden. In this approach, the UQ was achieved via a combination of several derived ensembles from a fixed optimum topology subjected to randomly switched off weights, which allow predictability with one forward pass. The process was developed and programmed to provide trackable performance in a specific task and access to a wide variety of different internal characteristics and libraries. A comparison of performance with Monte Carlo dropout and quantile regression using computer vision and control task metrics showed significant progress in the ARDCW. This approach does not require changes in the optimization process and can be applied to already trained topologies in a way that outperforms other models. 

  • 34.
    Abbaszadeh Shahri, Abbas
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering. Islamic Azad University.
    An Optimized Artificial Neural Network Structure to Predict Clay Sensitivity in a High Landslide Prone Area Using Piezocone Penetration Test (CPTu) Data: A Case Study in Southwest of Sweden2016In: Geotechnical and Geological Engineering, ISSN 0960-3182, E-ISSN 1573-1529, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Application of artificial neural networks (ANN) in various aspects of geotechnical engineering problems such as site characterization due to have difficulty to solve or interrupt through conventional approaches has demonstrated some degree of success. In the current paper a developed and optimized five layer feed-forward back-propagation neural network with 4-4-4-3-1 topology, network error of 0.00201 and R2 = 0.941 under the conjugate gradient descent ANN training algorithm was introduce to predict the clay sensitivity parameter in a specified area in southwest of Sweden. The close relation of this parameter to occurred landslides in Sweden was the main reason why this study is focused on. For this purpose, the information of 70 piezocone penetration test (CPTu) points was used to model the variations of clay sensitivity and the influences of direct or indirect related parameters to CPTu has been taken into account and discussed in detail. Applied operation process to find the optimized ANN model using various training algorithms as well as different activation functions was the main advantage of this paper. The performance and feasibility of proposed optimized model has been examined and evaluated using various statistical and analytical criteria as well as regression analyses and then compared to in situ field tests and laboratory investigation results. The sensitivity analysis of this study showed that the depth and pore pressure are the two most and cone tip resistance is the least effective factor on prediction of clay sensitivity.

  • 35.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics. College of Civil Engineering, Roudehen branch, Islamic Azad University, Tehran, Iran.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    CPT-SPT correlations using artificial neural network approach: A Case Study in Sweden2015In: Electronic Journal of Geotechnical Engineering, E-ISSN 1089-3032, Vol. 20, no 28, p. 13439-13460Article in journal (Refereed)
    Abstract [en]

    The correlation between Standard and Cone Penetration Tests (SPT and CPT) as two of the most used in-situ geotechnical tests is of practical interest in engineering designs. In this paper, new SPT-CPT correlations for southwest of Sweden are proposed and developed using an artificial neural networks (ANNs) approach. The influences of soil type, depth, cone tip resistance, sleeve friction, friction ratio and porewater pressure on obtained correlations has been taken into account in optimized ANN models to represent more comprehensive and accurate correlation functions. Moreover, the effect of particle mean grain size and fine content were investigated and discussed using graph analyses. The validation of ANN based correlations were tested using several statistical criteria and then compared to existing correlations in literature to quantify the uncertainty of the correlations. Using the sensitivity analyses, the most and least effective factors on CPT-SPT predictions were recognized and discussed. The results indicate the ability of ANN as an attractive alternative method regarding to conventional statistical analyses to develop CPT-SPT relations.

  • 36.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Updated relations for the uniaxial compressive strength of marlstones based on P-wave velocity and point load index test2016In: INNOVATIVE INFRASTRUCTURE SOLUTIONS, ISSN 2364-4176, Vol. 1, no 1, article id UNSP 17Article in journal (Refereed)
    Abstract [en]

    Although there are many proposed relations for different rock types to predict the uniaxial compressive strength (UCS) as a function of P-wave velocity (V-P) and point load index (Is), only a few of them are focused on marlstones. However, these studies have limitations in applicability since they are mainly based on local studies. In this paper, an attempt is therefore made to present updated relations for two previous proposed correlations for marlstones in Iran. The modification process is executed through multivariate regression analysis techniques using a provided comprehensive database for marlstones in Iran, including UCS, V-P and Is from publications and validated relevant sources comprising 119 datasets. The accuracy, appropriateness and applicability of the obtained modifications were tested by means of different statistical criteria and graph analyses. The conducted comparison between updated and previous proposed relations highlighted better applicability in the prediction of UCS using the updated correlations introduced in this study. However, the derived updated predictive models are dependent on rock types and test conditions, as they are in this study.

  • 37.
    Abbaszadeh Shahri, Abbas
    et al.
    Department of Civil Engineering, Islamic Azad University, Roudehen Branch, Tehran, Iran Johan Lundberg AB, Uppsala, Sweden.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Renkel, Crister
    Johan Lundberg AB, Uppsala, Sweden.
    Correction to: Artificial intelligence models to generate visualized bedrock level: a case study in Sweden (Modeling Earth Systems and Environment, (2020), 6, 3, (1509-1528), 10.1007/s40808-020-00767-0)2020In: Modeling Earth Systems and Environment, ISSN 2363-6203, E-ISSN 2363-6211, Vol. 6, no 4Article in journal (Refereed)
    Abstract [en]

    In the original version of this article, unfortunately a character of the Journal no in the reference 10 has been published incorrectly.

  • 38.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Naderi, Shima
    Modified correlations to predict the shear wave velocity using piezocone penetration test data and geotechnical parameters: a case study in the southwest of Sweden2016In: INNOVATIVE INFRASTRUCTURE SOLUTIONS, ISSN 2364-4176, Vol. 1, no 1, article id UNSP 13Article in journal (Refereed)
    Abstract [en]

    Shear wave velocity (VS) is an important geotechnical characteristic for determining dynamic soil properties. When no direct measurements are available, V-S can be estimated based on correlations with common in situ tests, such as the piezocone penetration test (CPTu). In the current paper, three modified equations to predict the V-S of soft clays based on a comprehensive provided CPTu database and related geotechnical parameters for southwest of Sweden were presented. The performance of the obtained relations were examined and investigated by several statistical criteria as well as graph analyses. The best performance was observed by implementing of corrected cone tip resistance (q(t)) and pore pressure ratio (B-q) which directly can be found from CPTu data. The introduced modifications were developed and validated for available soft clays of the studied area in southwest of Sweden, and thus, their applicability for proper prediction in other areas with different characteristics should be controlled. However, the used method as a suitable tool can be employed to investigate.

  • 39.
    Abbaszadeh Shahri, Abbas
    et al.
    JohanLundberg AB.
    Shan, Chunling
    Tyréns.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Visualisering av bergtopografi med artificiell intelligens2022In: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, Vol. 114, no 1, p. 44-46Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Rumslig fördelning av djup till berggrunden (DTB) är en viktig ochutmanande fråga i många geotekniska tillämpningar. På grund av att DTBassocieras med säkerhet och ekonomi i jord- och bergkonstruktionerkan generering av mer precisa modeller vara av avgörande betydelse.Med hjälp av resultat från Jb-sonderingar för ett infrastrukturprojekt iStockholm har vi skapat en optimerad visualiserad 3D -prediktiv DTBmodellvia en automatiserad artificiell intelligent datormetod (AI) ochjämfört den med den metod som ofta används, det geostatistiskaverktyget Ordinary Kriging (OK).

  • 40.
    Abbaszadeh Shahri, Abbas
    et al.
    Johan Lundberg AB, S-75450 Uppsala, Sweden.;Tyrens, Div Rock Engn, S-11886 Stockholm, Sweden..
    Shan, Chunling
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics. Tyrens, Div Rock Engn, S-11886 Stockholm, Sweden..
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Normalizing Large Scale Sensor-Based MWD Data: An Automated Method toward A Unified Database2024In: Sensors, E-ISSN 1424-8220, Vol. 24, no 4, article id 1209Article in journal (Refereed)
    Abstract [en]

    In the context of geo-infrastructures and specifically tunneling projects, analyzing the large-scale sensor-based measurement-while-drilling (MWD) data plays a pivotal role in assessing rock engineering conditions. However, handling the big MWD data due to multiform stacking is a time-consuming and challenging task. Extracting valuable insights and improving the accuracy of geoengineering interpretations from MWD data necessitates a combination of domain expertise and data science skills in an iterative process. To address these challenges and efficiently normalize and filter out noisy data, an automated processing approach integrating the stepwise technique, mode, and percentile gate bands for both single and peer group-based holes was developed. Subsequently, the mathematical concept of a novel normalizing index for classifying such big datasets was also presented. The visualized results from different geo-infrastructure datasets in Sweden indicated that outliers and noisy data can more efficiently be eliminated using single hole-based normalizing. Additionally, a relational unified PostgreSQL database was created to store and automatically transfer the processed and raw MWD as well as real time grouting data that offers a cost effective and efficient data extraction tool. The generated database is expected to facilitate in-depth investigations and enable application of the artificial intelligence (AI) techniques to predict rock quality conditions and design appropriate support systems based on MWD data.

  • 41.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Kartering av skredbenägenhet medartificiell intelligens2018In: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, no 1Article in journal (Other academic)
  • 42.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Landslide susceptibility hazard map in southwest Sweden using artificial neural network2019In: Catena (Cremlingen. Print), ISSN 0341-8162, E-ISSN 1872-6887, Vol. 183, article id UNSP 104225Article in journal (Refereed)
    Abstract [en]

    Landslides as major geo-hazards in Sweden adversely impact on nearby environments and socio-economics. In this paper, a landslide susceptibility map using a proposed subdivision approach for a large area in southwest Sweden has been produced. The map has been generated by means of an artificial neural network (ANN) model developed using fourteen causative factors extracted from topographic and geomorphologic, geological, land use, hydrology and hydrogeology characteristics. The landslide inventory map includes 242 events identified from different validated resources and interpreted aerial photographs. The weights of the causative factors employed were analyzed and verified using accepted mathematical criteria, sensitivity analysis, previous studies, and actual landslides. The high accuracy achieved using the ANN model demonstrates a consistent criterion for future landslide susceptibility zonation. Comparisons with earlier susceptibility assessments in the area show the model to be a cost-effective and potentially vital tool for urban planners in developing cities and municipalities.

  • 43.
    Abbaszadeh Shahri, Abbas
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Spross, Johan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Johansson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Larsson, Stefan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Soil and Rock Mechanics.
    Storskalig kartering av skredbenägenhet i västra Götaland med artificiell intelligens2018Conference paper (Other academic)
  • 44.
    Abbott, D. Wade
    et al.
    Agr & Agri Food Canada, Lethbridge Res & Dev Ctr, 5403-1 Ave South, Lethbridge, AB T1J 4B1, Canada..
    Aasen, Inga Marie
    SINTEF Ind, Dept Biotechnol & Nanomed, N-7465 Trondheim, Norway..
    Beauchemin, Karen A.
    Agr & Agri Food Canada, Lethbridge Res & Dev Ctr, 5403-1 Ave South, Lethbridge, AB T1J 4B1, Canada..
    Gröndahl, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Gruninger, Robert
    Agr & Agri Food Canada, Lethbridge Res & Dev Ctr, 5403-1 Ave South, Lethbridge, AB T1J 4B1, Canada..
    Hayes, Maria
    Teagasc Food Res Ctr, Food BioSci Dept, Dublin D15 KN3K 15, Ireland..
    Huws, Sharon
    Queens Univ Belfast QUB, Belfast BT7 1NN, Antrim, North Ireland..
    Kenny, David A.
    Anim Biosci Res Ctr, Dunsany 5 PW93, Meath, Ireland..
    Krizsan, Sophie J.
    Swedish Univ Agr Sci, Dept Agr Res Northern Sweden, SE-90183 Umeå, Sweden..
    Kirwan, Stuart E.
    Anim Biosci Res Ctr, Dunsany 5 PW93, Meath, Ireland..
    Lind, Vibeke
    Norwegian Inst Bioecon Res NIBIO, Post Box 115, N-1431 As, Norway..
    Meyer, Ulrich
    Fed Res Inst Anim Hlth, Friedrich Loeffler Inst FLI, Bundesforsch Inst Tiergesundheit, D-38116 Braunschweig, Germany..
    Ramin, Mohammad
    Swedish Univ Agr Sci, Dept Agr Res Northern Sweden, SE-90183 Umeå, Sweden..
    Theodoridou, Katerina
    Queens Univ Belfast QUB, Belfast BT7 1NN, Antrim, North Ireland..
    von Soosten, Dirk
    Fed Res Inst Anim Hlth, Friedrich Loeffler Inst FLI, Bundesforsch Inst Tiergesundheit, D-38116 Braunschweig, Germany..
    Walsh, Pamela J.
    Queens Univ Belfast QUB, Belfast BT7 1NN, Antrim, North Ireland..
    Waters, Sinead
    Anim Biosci Res Ctr, Dunsany 5 PW93, Meath, Ireland..
    Xing, Xiaohui
    Agr & Agri Food Canada, Lethbridge Res & Dev Ctr, 5403-1 Ave South, Lethbridge, AB T1J 4B1, Canada..
    Seaweed and Seaweed Bioactives for Mitigation of Enteric Methane: Challenges and Opportunities2020In: Animals, E-ISSN 2076-2615, Vol. 10, no 12, article id 2432Article, review/survey (Refereed)
    Abstract [en]

    Simple Summary The need to become more efficient in agriculture and the food industry exists parallel to the challenge of climate change. Meat and dairy production is the target of much scrutiny due to methane (CH4) emissions and global warming. On the other hand, it should be noted that two-thirds of the world's agricultural land consists of pastures and permanent grasslands and is used for livestock grazing. This land is predominantly unsuitable for arable purposes but facilitates the production of high-quality human-edible protein in the form of ruminant animal-derived meat and milk. This makes a significant contribution to feeding the world's population. There is a need to reduce CH4 emissions, however, and several approaches are being researched currently. Seaweeds are diverse plants containing bioactives that differ from their terrestrial counterparts and they are increasingly under investigation as a feed supplement for the mitigation of enteric CH4. Seaweeds are rich in bioactives including proteins, carbohydrates and to a lesser extent lipids, saponins, alkaloids and peptides. These bioactives could also play a role as feed ingredients to reduce enteric CH4. This review collates information on seaweeds and seaweed bioactives and their potential to impact on enteric CH4 emissions. Seaweeds contain a myriad of nutrients and bioactives including proteins, carbohydrates and to a lesser extent lipids as well as small molecules including peptides, saponins, alkaloids and pigments. The bioactive bromoform found in the red seaweed Asparagopsis taxiformis has been identified as an agent that can reduce enteric CH4 production from livestock significantly. However, sustainable supply of this seaweed is a problem and there are some concerns over its sustainable production and potential negative environmental impacts on the ozone layer and the health impacts of bromoform. This review collates information on seaweeds and seaweed bioactives and the documented impact on CH4 emissions in vitro and in vivo as well as associated environmental, economic and health impacts.

  • 45.
    Abd Ullah Alhamo, Ali
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Alahmad, Hussain
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Småhusprojekt och fördjupning: Fördjupning: Reducering av U-värdet i ett fönster2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 46.
    Abdali, Yasser
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Holm, Lovisa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    En jämförelse mellan Tekla Structures och Civil 3D i krökta betongkonstruktioner2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Within the construction industry, there is a lot of discussion around BIM (Building InformationModelling). There is a need to move away from customized 2D-drawings and instead focus oninformative models which can be used throughout the whole cycle of construction. This developmenthas been ongoing within house construction, but this approach is harder to implement within thefacility sector.The difficulty in implementing a more BIM-oriented approach within construction is partly due tosoftware currently not being fully developed to create informative and reliable models of constructionswith complex geometries, such as bridges.Since Trafikverket, the largest construction developer within Sweden, has started to place a largerdemand on 3D there is a need for both technology and human resource to develop.The aim of this dissertation is to present a case study investigating the suitability of the software TeklaStructure and AutoCAD Civil 3D to perform a 3D-model of a double-curved bridge. The two pieces ofsoftware will be contrasted in a final comparison whereby both pros and cons will be presented.The study has made it clear that BIM is not just about creating an informative model, but it is alsoabout an approach which has the ability to completely change the construction sector to work morecollaboratively and effectively.The comparison between the two relevant software in this study shows that they both have strengthsand weaknesses and are suitable for our purpose. However, they differ in how detailed models theycan create and how well they have the ability to work with BIM to a greater extent.

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  • 47.
    Abdalla, Ahmed
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Satellite Positioning.
    Determination of a gravimetric geoid model of Sudan using the KTH method2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main objective of this study is to compute a new gravimetric geoid model of Sudan

    using the KTH method based on modification of Stokes’ formula for geoid determination.

    The modified Stokes’ formula combines regional terrestrial gravity with long-wavelength

    gravity information provided by the global gravitational model (GGM). The collected

    datasets for this study contained the terrestrial gravity measurements, digital elevation

    model (DEM), GPS/levelling data and four global gravitational Models (GGMs), (EGM96,

    EIGEN-GRACE02S, EIGEN-GL04C and GGM03S).

    The gravity data underwent cross validation technique for outliers detection, three gridding

    algorithms (Kriging, Inverse Distance Weighting and Nearest Neighbor) have been tested,

    thereafter the best interpolation approach has been chosen for gridding the refined gravity

    data. The GGMs contributions were evaluated with GPS/levelling data to choose the best

    one to be used in the combined formula.

    In this study three stochastic modification methods of Stokes’ formula (Optimum, Unbiased

    and Biased) were performed, hence an approximate geoid height was computed. Thereafter,

    some additive corrections (Topographic, Downward Continuation, Atmospheric and Ellipsoidal)

    were added to the approximated geoid height to get corrected geoid height.

    The new gravimetric geoid model (KTH-SDG08) has been determined over the whole

    country of Sudan at 5′ x 5′ grid for area ( 4 ). The optimum method

    provides the best agreement with GPS/levelling estimated to 29 cm while the agreement for

    the relative geoid heights to 0.493 ppm. A comparison has also been made between the new

    geoid model and a previous model, determined in 1991 and shows better accuracy.

    􀁄 ≤φ ≤ 23􀁄 , 22􀁄 ≤ λ ≤ 38􀁄

    Keywords: geoid model, KTH method, stochastic modification methods, modified Stokes’ formula,

    additive corrections.

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  • 48.
    Abdalnour, Jemy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Abdirahman, Mohamed Ibrahim
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Kritiska vippningslaster för kompositbalkar/lättbalkar av trä2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis has focused on the calculation of critical loads for lateral torsional buckling forthree selected wood-based composite beams with varying heights based on the availableMasonite Beams standard range. The main objective has been to investigate and compare ahand calculation model with the recommended method in Eurocode 5, as well as comparethem with results from finite element analysis.In this study, two instability phenomena have been addressed, namely lateral torsionalbuckling and flexural column buckling. The reason for addressing flexural columnbuckling is that the Eurocode method is based on a simplified flexural column bucklingmodel to facilitate the calculation of the moment carrying capacity regarding lateraltorsional buckling for I-beams subjected to bending.The hand calculation model used in this study is based on classical stability theory. Itis applied to a cross-section that differs moderately from the actual cross-section, whichin turn underestimates the load-bearing capacity. As lightweight beams are composed oftwo different wood-based materials, the cross-section has been transformed to a fictitiouscross-section to facilitate the hand calculation. In the pursuit of more realistic results, afinite element model has been established, and two analyses based on this model havebeen performed.The beams are assumed to be supported at the ends under forked conditions, which meansthat they are free to deflect vertically and laterally but the rotation about the beam axis isfixed. They have been examined for three load cases, namely constant bending moment,point load at the midpoint, and uniformly distributed load.By comparing the results obtained from the hand calculation and the Eurocode method,this study concludes that the Eurocode method significantly underestimates the momentcapacity and is applicable to braced beams. However, the hand calculation overestimatesthe moment capacity, as evident 

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  • 49.
    Abdalnour, John
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Saliba, Milad
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Drop-weight impact tests on reinforced concrete beams2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master's thesis aimed to investigate the behaviour of reinforced concrete beams under dynamic loading conditions, specifically focusing on understanding shear failure. The study was conducted with KTH Royal Institute of Technology, the Swedish Fortifications Agency, and Tyréns. The research built upon previous studies and aimed to contribute to understanding dynamically loaded concrete structures.The thesis included a literature study to explore the fundamental concepts of dynamics, impulse loading, and the response of RC structures under dynamic and static loading. The experimental part involved manufacturing and testing 27 reinforced concrete (RC) beams with varying amounts of transverse reinforcement and load positions, where 18 were tested dynamically, and the rest were tested statically. The findings contribute to understanding structural response and failure mechanisms in such beams, considering three main factors: load position, shear reinforcement, and loading characteristics. In addition, essential data, such as reaction forces, beam displacements, and crack patterns, were measured using load cells, accelerometers, and high-speed cameras.The findings of the study revealed several important insights. The load's position significantly affected the beams' acceleration, with further load positions activating both shear and flexural modes simultaneously. Beams with different shear reinforcement configurations exhibited similar behaviour and the presence of weaker cross-sections due to insufficient bonding between steel and concrete. The study also demonstrated that dynamic loading increased the beams' load capacity compared to static loading, attributed to the strain rate effect and inertia forces. The crack patterns and residual eigenfrequency differed between dynamic and static loading conditions, with dynamic loading resulting in less extensive cracking and reduced residual stiffness.The use of a fiberboard provided cushioning effects, as its removal during testing resulted in a shorted load duration and the formation of the cracks in the beams. In addition, anchoring the flexural reinforcement significantly increased the stiffness of the beams, leading to an earlier rebound and a more robust impact response.

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  • 50.
    Abdalnour, John
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Zahid, Yasir
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Småhusprojekt och fördjupning: Fördjupning: Kvalitativ jämförelse mellan trä och betong2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
1234567 1 - 50 of 28358
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