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- Zalejska-Jonsson, Agnieszka, 1978-
(författare)
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In the Business of Building Green : The value of low-energy residential buildings from customer and developer perspectives
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- An overarching aim of this research was to investigate the comprehensive value of green residential buildings as seen from two perspectives: that of the developer and that of the occupant (the customer). The dissertation consists of studies presented in seven papers. The studies conducted to investigate the developer’s perspective focused on construction cost and potential profit (papers I and VII). The customer’s perspective was examined with three approaches: the impact that energy and environment have on the decision to purchase (or rent) an apartment (paper V), willingness to pay for a green apartment (paper VI) and finally, the occupants’ satisfaction with the dwelling and indoor environment (papers II, III and IV). The first paper examines whether increased investment costs are profitable, taking into account the reduction in operating costs. The investment viability is approached by comparing investment in conventional and green residential building, particularly passive houses, using real construction and post-occupancy conditions. The increased investment costs in energy-efficient building were also the focus of paper VII. In this paper, the aim was to study how technologies used in energy-efficient residential building construction affect the available saleable floor area and how this impacts on the profitability of the investment. Potential losses and gains of saleable floor area in energy-efficient buildings were assessed using a modelled building and analysed with the help of the average construction cost.Papers II and IV present results from a study of occupants’ satisfaction and indoor environmental qualities. Both papers aim at comparing and analysing responses from occupants living in green and conventional buildings. Paper III focuses on a similar subject, but investigates occupants’ satisfaction among all adults living in multi-family buildings in Sweden, providing a national context for the results presented in papers II and IV. The results indicate that occupants are generally satisfied with their dwellings, but indoor environment proved to have a statistically significant effect on overall satisfaction.The results in paper V indicate that energy and environmental factors have a minor impact on customers’ decision to purchase or rent an apartment. However, availability of information on building energy and environmental performance may have an effect on the likelihood of the buyers’ being interested in environmental qualities and consequently an impact on their decision. The study presented in paper VI shows that customer interest in energy and environmental factors has a significant impact on stated willingness to pay for green dwellings. The paper discusses the stated willingness to pay for low-energy buildings and buildings with an environmental certificate and attempts to assess the rationale of the stated willingness to pay for low-energy dwellings given potential energy savings.
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| 3. |
- Deckner, Fanny, 1984-
(författare)
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Ground vibrations due to pile and sheet pile driving : influencing factors, predictions and measurements
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ground vibrations due to pile driving are part of a complex process. Vibration is generated from the pile driver to the pile. As the pile interacts with the surrounding soil, vibrations are transferred at the pile-soil interface. The vibration propagates through the ground and interacts with structures, both above ground and underground. The vibration continues into the structure where it may disturb occupants and/or damage the structure.In this thesis the study of the vibration transfer process due to pile driving is limited to the vibration source and the wave propagation in the soil. Vibration transmission to adjacent buildings and structures is not studied. However, impact of vibrations on buildings is briefly discussed in the literature study.It is important to accurately predict the magnitude of ground vibrations that result from pile driving in urban areas, both over- and underestimated vibration levels lead to increased costs. A lot of research has been performed within this field of knowledge, but a reliable and acknowledged prediction model for vibrations induced by pile or sheet pile driving is still needed.The objective of the research project is to increase the knowledge and understanding in the field of ground vibrations due to impact and vibratory driving of piles and sheet piles. This research project also aims to develop a reliable prediction model that can be used by practising engineers to estimate vibration due to pile driving. This licentiate thesis presents the first part of the research project and aims to increase the knowledge and understanding of the subject and to form a basis for continued research work.The most important findings and conclusions from this study are:The main factors influencing vibrations due to pile and sheet pile driving are; (1) the vibrations transferred from the pile to the soil, (2) the geotechnical conditions at the site and (3) the distance from the source.The vibrations transmitted from the pile to the soil depend on the vibrations transferred to the pile from the hammer, the pile-soil interaction and the wave propagation and attenuation in the plastic/elasto-plastic zone closest to the pile.There is today no prediction model that fulfils the criteria of the “perfect” prediction model; reliable but yet easy to apply.Future research should study the transfer of vibrations at the pile-soil interface, including the generation of a plastic/elasto-plastic zone in the area closest to the pile and how that affects the transfer of vibrations from the pile to the soil.
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| 4. |
- Deckner, Fanny
(författare)
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Vibration transfer process during vibratory sheet pile driving : from source to soil
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Vibratory driven sheet piles are a cost-effective retaining wall structure, and in coming decades the continued use of this method will be crucial for minimising costs within the construction sector. However, vibratory driven sheet piles are a source of ground vibrations, which may harm structures or induce disturbance. Most urban construction projects face strict limits on permissible vibration level. Being able to reliably predict the expected vibration level prior to construction is therefore highly important. Reliable prediction demands a profound knowledge of the vibration transfer process, from source to point of interest. This thesis focuses on clarifying the vibration transfer process and will serve as a platform for the future development of a reliable prediction model. The vibration transfer process is divided into two main parts: vibration source and vibrations in soil. The different parts in the vibration transfer process are studied and investigated with the help of a literature review, field tests and numerical modelling. Within the scope of this thesis, three field tests have been conducted and a new instrumentation system has been developed. The new instrumentation system enables recording of both sheet pile vibrations and ground vibrations at depth during the entire driving. The field tests aimed to study the vibration transfer from sheet pile to soil and the vibration transfer within a sheet pile wall, as well as the wave pattern in soil. To study sheet pile behaviour during driving a numerical model was developed, which is also meant to serve as a basis for further studies. The main scientific contribution of this thesis is the identification of the sheet pile behaviour during driving. For practical application, the main contribution is the development of an increased knowledge of the vibration transfer process from source to soil, together with the new instrumentation system and the development of the numerical model.
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- Johansson, Teddy, 1960-
(författare)
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Artificial Ground Freezingin Clayey Soils : Laboratory and Field Studies of Deformations During Thawing at the Bothnia Line
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Artificial ground freezing as a method to temporarily stabilize and create hydraulic sealing in urban as well as in rural areas has been used in a number of Swedish construction projects, particularly during the last decade. One problem with the freezing of soil and rock is that fine-grained clayey types of soils have showed a tendency to under certain circumstances, during the thawing process, create a pore water overpressure and to consolidate, despite a change in the external loading conditions. In certain cases, this condition can be a desired effect as the soil mass after a freeze- and thaw cycle acquires overconsolidated properties. The main objectives of this study are, to describe and review the knowledge and current state of practice of artificial ground freezing, to increase the understanding about the conceptual behaviour for prognosis of the vertical deformation concerning artificial ground freezing and to compare and discuss results from laboratory and field studies concerning vertical deformation during thawing process for Bothnia soil. The field studies and the laboratory tests in this research study have been performed with soil from the freezing of the Bothnia Line in the vicinity of Stranneberget. The Bothnia Line is the railway link between Nyland, north of Kramfors, and Umeå. This thesis relates to a part of the Bothnia Line. It deals with the behaviour of soil during thawing by means of temporary stabilization and hydraulic sealing of fine-grained soil through artificial freezing using brine as the cooling agent. However, the reason behind the problem consists of the final deformations due to the thawing process. The general conclusions of this study are; the Bothnia soil water content decreased in mean approximately 14 % after a freeze-thaw cycle, which approximately corresponds to; wth = 0.8w – 1.5 the decrease of the water content has no correlation to the depth below ground surface, in contrast, there is a strong correlation between the undisturbed soil water content and the magnitude of the decrease in water content the soil liquid limit decreases after a freeze-thaw cycle, simultaneously as the relative share of clay and fine silt grains decreases while the relative share of more coarse grains increases the coarser and denser soil created after a freeze-thaw cycle obtains an increased preconsolidation pressure and an increased undrained shear strength.
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| 6. |
- Lucian, Charles, 1963-
(författare)
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Geotechnical Aspects of Buildings on Expansive Soils in Kibaha, Tanzania
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The focus of this study is on potential damages to buildings resulting from expansive soils in Tanzania, particularly clay soils in Kibaha. For the fact that most of the affected structures are founded on expansive soils, a clear understanding of the behaviour of soils and their interaction with structures has been of interest to the study in order to evaluate properly the source of the problem.The geotechnical behaviour of expansive clay soils is investigated by looking into the geomorphologic, geological and climatic conditions and mineralogical composition of the soils in the study area.Two sites, representative of known problem-areas in Kibaha were selected for geotechnical tests. Geotechnical site investigation consisted of open trial pits, profile description and the collection of both disturbed and undisturbed samples. To extend and amplify the findings, supplementary samples were collected from the environs of the two sites.The collected samples were submitted to soil laboratories at KTH, ARU, SEAMIC and DIT for mineralogical composition tests, natural water content, density, Atterberg limits and swell tests. The results of this investigation indicate that soils in Kibaha contains clay (31%), have high liquid limit (59%) and plastic limit (37%) which indicate high potential swell.Since swell pressure, free swell and swell percent are key properties of expansive soils, the swell properties were measured by free swell tests and one-dimensional oedometer swell tests. The free swell ranged from 100% to 150% and the swell pressure was in the region of 45 kPa. The coefficient of linear extensibility (COLE) was determined for characterizing expansive clays. For all tested samples, COLE ranged from 0.09 to 0.14 indicating that soils fall in the region of high to very high expansion potential rating. The properties of expansive soils were confirmed by the x-ray diffraction test which showed the presence of smectite in the soil. Furthermore, total suction measurement technique using filter paper method indicated that the soils have high suction values, signifying that they have a tendency to swell upon wetting depending on plasticity of particular soil.The depth of the active zone was measured as a function of moisture variations in the profiles during two extreme weather conditions. The active zone depth was found to be between 1.0 and 2.0 m deep. Procedures to assess models to predict swell in the case study were outlined together with their validity.Vertical and horizontal spatial variability in selected soil properties was defined using geostatistical techniques through the fitting of variogram. The indicator semivariograms of both clay contents and free swell gave a range of 20 m horizontally and 1.0 m vertically, with the horizontal variograms exhibiting greater ranges than the dipping variograms.Physical conditions of the surveyed properties in the area confirmed that building damages are associated with poor building materials triggered by expansive soils. In support of the obtained data, the actual behaviour of the foundations was supplemented with prototypes of strip foundations whose performances were monitored over a period of four months. Finally, suggested are the ways forward to solve the problem of foundation on expansive soil
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