| 1. |
- Karstunen, Minna, 1965
(författare)
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Så bygger vi på säker grund
- 2015
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Ingår i: Kan vi tackla det nya klimatet? Formas Fokuserar 24.. - 9789154060863 ; , s. 121-128
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Erlingsson, Sigurdur, 1960-, et al.
(författare)
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Correlating Air Freezing Index and Frost Penetration Depth : A Case Study for Sweden
- 2020
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Ingår i: Lecture Notes in Civil Engineering. - Cham : Springer. ; , s. 847-857, s. 847-857
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The determination of frost penetration is one of the main requirements in considering environmental effects in pavement design in cold regions. At the present time, the frost depth of pavements in Sweden is estimated computationally using computer software which approximates the heat equation by finite difference. Due to the geographical positioning of Sweden, a wide range of air freezing index and frost penetration depths were observed with lower values in the south and higher values in the north. This paper introduces a simplified design chart which is obtained by empirically correlating the air freezing index estimated from temperature measurements by 44 local meteorological stations to the maximum frost penetration depth obtained by 49 RWIS Road Weather Information Station data. The results are classified depending on their location and the climatic zones defined by the Swedish pavement design codes. Nonlinear prediction intervals are implemented to provide a range of possible frost penetration depths since local site conditions are not taken into account. Further research is required to consider local on-site effects such as frost susceptibility of pavement materials, the thermal conductivity of layers, access to water and snow covering.
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| 3. |
- Karlsson, Mats, 1974, et al.
(författare)
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On the benefits of incorporating anisotropy in stability analyses in sensitive clays
- 2017
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Ingår i: Advances in Natural and Technological Hazards Research. - Cham : Springer International Publishing. - 1878-9897 .- 2213-6959. ; , s. 259-266
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- During construction of E45 - Norge/Vänerbanan, analyses of an area located in Agnesberg, just north of Gothenburg, showed an evaluated factor of safety significantly less than prescribed in the codes for both the new main road E45 and the new railway Norge/Vänerbanan. The road and railway are situated very close to each other, just next to the Göta River that complicates the evaluation of the safety factor. The empiricism commonly used was questioned due to an unfamiliar change in undrained shear strength in the profile. Consequently, an extensive field and laboratory campaign was conducted to establish a more accurate and reliable strength profile. The extensive laboratory programme contained a number of direct simple shear tests, as well as triaxial tests in both compression and extension to be able to determine the strength anisotropy in the area. The laboratory study showed that the soft clay in the area was more anisotropic than anticipated, which was more favourable in the studied case regarding the stability. This lead to a new anisotropic function to be used in evaluation of the safety factor. This combined with a general increase in undrained shear strength for the entire profile highlights the potential cost savings resulting from extensive site investigation that incorporates evaluation the magnitude of strength anisotropy.
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| 4. |
- Mangraviti, Viviana, 1991
(författare)
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Displacement-Based Design of Geosynthetic-Reinforced Pile-Supported Embankments to Increase Sustainability
- 2022
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Ingår i: SpringerBriefs in Applied Sciences and Technology. - Cham : Springer International Publishing. - 2191-530X .- 2191-5318. ; , s. 83-96
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Although the construction of concrete piles has a relevant environmental footprint, they are commonly used to reduce settlements of embankments on soft soil strata. A more sustainable choice to further reduce settlements (and, consequently, the number of piles) is to place geosynthetics below the embankment. However, existing design methods cannot calculate settlements at the embankment top and cannot be used to optimise the number of piles in a displacement-based design. In this note, an innovative model for assessing settlements at the top of Geosynthetic-Reinforced and Pile-Supported embankments induced by the embankment construction process is presented and validated against finite difference numerical analyses. The model is used to optimise the design of both piles and geosynthetic, and applied to a practical example, where the mass of CO2 saved by designing geosynthetics to reduce the pile number.
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| 5. |
- Nielsen, Jens, 1963, et al.
(författare)
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Reproducibility of railway noise measurements—influence of weather and test site conditions
- 2018
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Ingår i: Notes on Numerical Fluid Mechanics and Multidisciplinary Design. - Cham : Springer International Publishing. - 1612-2909 .- 1860-0824. ; , s. 167-179
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Requirements on monitoring stations to guarantee good reproducibility of measured railway noise data from one test site to another are investigated by field measurements and numerical simulations. Based on data from a monitoring system installed at Deutsch-Wagram in Austria, the influence of weather conditions (temperature, rain and snow) on pass-by noise levels and rail vibration is assessed. The influence of temperature on track decay rates (TDR) has been determined from pass-by analysis (PBA). It is concluded that the track superstructure design used at Deutsch-Wagram (60 kg/m rails, rail pads with dynamic stiffness in the order of 700–1000 kN/mm, and monobloc concrete sleepers on ballast) is appropriate for noise monitoring since the variation of measured noise levels for the studied range of weather conditions has a standard deviation of less than 2 dB. For such a track design, it is not essential to apply a correction procedure to account for seasonal variations (except in the case of snow). Further, a numerical parameter study of the influence of TDR and ground conditions (horizontal ground surface level relative to top of rail, and ground impedance based on a single value effective flow resistivity parameter) on predicted noise level is performed using TWINS. It is found that for ground surfaces with low sound reflection, the influence of ground surface level (when varying from 0.2 to 2 m) on predicted pass-by noise level is in the order of 1 dB.
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| 6. |
- Persson, Peter, et al.
(författare)
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Fluid-Structure Interaction Analysis of Vibration Reduction in Pipe Systems
- 2014
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Ingår i: Dynamics of Civil Structures. ; Volume 4, s. 459-468
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Bokkapitel (refereegranskat)abstract
- Transmitted vibrations from water-pipe systems, involving supports standing on a concrete slab and the underlying ground, are investigated here. The effects of varying parameters of the supports, such as location, their elastic modulus and their cross-section, on the level of vibrations transmitted by the water-pipe system are analysed in order to minimise vibrations transmitted to sensitive parts in a facility. A finite element model involving use of both finite and infinite elements was employed for analyses in the frequency domain where account was taken of both fluid-structure interaction and soil-structure interaction. It was concluded from the analyses performed that the parameters of the supports had an appreciable effect on the vibration level in the facility.
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| 7. |
- Persson, Peter, et al.
(författare)
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Numerical Study of Reduction in Vibrations Induced by Water-Pipe System
- 2015
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Ingår i: Dynamics of Civil Structures. ; 2, s. 407-419
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Bokkapitel (refereegranskat)abstract
- In certain buildings such as synchrotrons and large ground telescopes, strict requirements are stated regarding the vibration levels. Both external and internal vibration sources, for example traffic and indoor water pumps, can have an appreciable effect on the vibration levels in the buildings. The synchrotron research facility MAX IV, which is currently under construction in Sweden, serves as an example case for the analyses. In MAX IV, several water-pipe systems used for cooling purposes will be placed near vibration sensitive equipment. These systems will transmit vibrations, into structural parts of the facility, which could exceed the vibration requirements. Structural modifications of pipe systems are investigated here by means of the finite element method in order to reduce vibration levels in the building. The finite element model employed includes a water-pipe system, adjacent building parts and the underlying soil. The use of fluid-structure interaction is investigated as well as the use of component mode synthesis. This paper focuses on the numerical procedure used as well as the effects on transmitted vibrations by different placements of the pipe supports.
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| 8. |
- Tran, Q.A., et al.
(författare)
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Modelling of the quickness test of sensitive clays using the generalized interpolation material point method
- 2017
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Ingår i: Advances in Natural and Technological Hazards Research. - Cham : Springer International Publishing. - 1878-9897 .- 2213-6959. ; , s. 323-336
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The presence of the sensitive clays in Scandinavia and Canada creates quick clay landslide hazards. The ability to predict the likelihood of such landslides occurrence, as well as their outreach would reduce the damage to the infrastructures and loss of life. Recently, a simple experimental technique named a quickness test (Thakur V, Degago S, Geotech Lett 2:87-95, 2012) has been employed to investigate the susceptibility of the clay to create large retrogression landslides. In this paper, we applied Generalized Interpolation Material Point Method (a numerical method suitable for large displacement dynamic problems) to replicate the quickness test experiment. The primary goal of the presented simulations is to further validate the modelling technique and the constitutive model used. In particular, the computations suggest the importance of the strain rates for the prediction of the run-out distance of the remoulded sensitive clays.
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| 9. |
- Wersäll, Carl, et al.
(författare)
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Vibration Source Localization along Railway Tracks
- 2012
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Ingår i: Noise and Vibration Mitigation for Rail Transportation Systems. - Berlin : Springer. - 9784431539261 ; , s. 267-274
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Bokkapitel (refereegranskat)abstract
- Ground-borne vibration from railway traffic is an increasing problem in urbanized areas and measures are often needed to minimize its effects on the environment. An important question when dealing with railway problems is to identify the source(s) of vibration emitted along the railway track. Once this information is available, it is often possible to mitigate the problem by improving stiffness of the railway track and/or to upgrade worn-out or damaged rail sections and turnouts. This paper describes a method which makes it possible to determine the locations of track sections which are likely to emit strong ground vibration. A purpose-built track-bound vehicle which can be vibrated continuously at different frequencies can identify track sections having unfavorable dynamic foundation conditions. A theoretical concept is proposed to calculate the potential of energy emission from the vehicle moving along the track. Further, an innovative method is presented which makes it possible to determine the location of vibration sources by measurement of ground vibrations from existing railway traffic. This information can be used to determine the location of track sections where remedial measures are needed. Results are presented, illustrating application of the concepts, which can also be applied to other types of vibration problems.
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| 10. |
- Athanasopoulos, Stefanos D., et al.
(författare)
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Mapping Grain Strains in Sand Under Load Using Neutron Diffraction Scanning
- 2018
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Ingår i: Micro to MACRO Mathematical Modelling in Soil Mechanics. - Cham : Springer International Publishing. - 2297-024X .- 2297-0215. - 9783319994734 - 9783319994741 ; , s. 23-33
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Bokkapitel (refereegranskat)abstract
- Towards the improvement of the understanding of force/stress distribution in granular media under load, a new experimental approach is suggested. Neutron diffraction, a non-conventional experimental technique, has been successfully used to map the evolution of intragranular strains in sand specimens loaded in a novel plane-strain apparatus. Representative preliminary results from recent experiments are presented, focusing on the correlation between the macro- and micro-scale response of the material, to highlight the potential of the experimental approach.
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