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Modeling of temperature variations and response in a mining road bridge in Kiruna

Fabricius, Mikael LU and Ekman, Henrik (2016) In TVBK-5255 VBK920 20161
Division of Structural Engingeering
Abstract
This thesis treats a concrete bridge located in Kiruna, in the north of Sweden, which was used for the mining industry. A finite element model has been created with the finite element software Abaqus to find out if it accurately can describe the variation of the temperature and deformation within the bridge over time. The temperature variations and deformations have been studied with respect to climate effects.
The climate is complex and affects the temperature within the bridge in different ways. During daytime the bridge is exposed to radiation from the sun and the air temperature which is relatively high during the studied time period. During the night the bridge will cool down due to outgoing longwave radiation and the absence of the... (More)
This thesis treats a concrete bridge located in Kiruna, in the north of Sweden, which was used for the mining industry. A finite element model has been created with the finite element software Abaqus to find out if it accurately can describe the variation of the temperature and deformation within the bridge over time. The temperature variations and deformations have been studied with respect to climate effects.
The climate is complex and affects the temperature within the bridge in different ways. During daytime the bridge is exposed to radiation from the sun and the air temperature which is relatively high during the studied time period. During the night the bridge will cool down due to outgoing longwave radiation and the absence of the sun. The temperature in the bridge is also affected by convection mainly caused by wind.
The used finite element model has previously been verified for two-dimensional temperature variation in concrete structures without overhangs. In this work the temperature variation will be studied in a cross section of the bridge using a two-dimensional model including overhang and paving layer. The temperature variation was studied for June 2009, August 2010, and a short period during June 2014. The strain was studied in a three dimensional model for June 2009.
The finite element model calculates the temperature variations within a structure based on climate input data. This data consists of hourly values of air temperature, long wave radiation and global radiation. The temperature input data was received from the Swedish Meteorological and Hydrological Institute which have weather stations placed across Sweden.
The temperature variations lead to deformations. An increase in temperature will force the concrete to expand, and a decrease in temperature will force the concrete to contract. The modelled deformations within the structure are also affected by how the supports are modelled and the choice of material properties.
After calculating the temperature variations it is possible to calculate the deformations based on the temperature calculation results. The temperature- and deformation results were compared to measurements from temperature and strain gauges by M.Sc. Niklas Bagge and his co-workers from Luleå Technical University.
The results show that the 2D temperature model captures the temperature variation very well. Further the results show that the 3D strain model captures the strain variation fairly well and the 2D strain model shows unreliable results. (Less)
Abstract (Swedish)
Den här studien har utförts på en bro i Kiruna, i norra Sverige, som användes till gruvindustrin. En modell av bron skapades med finita elementmetoden i programvaran Abaqus 6.14 för att ta reda på huruvida temperatur- och töjningsvariationerna på bron på grund av klimatets påverkan kan beskrivas.
Klimatets temperaturpåverkan på bron är komplex. Under dagtid påverkas bron av strålning från solen och luftens temperatur som är relativt hög under den tid som bron har studerats. Under natten sker en temperatursänkning i bron på grund av utgående långvågig strålning och den relativt låga lufttemperaturen. Temperaturen i bron påverkas även av konvektion som uppstår då vinden träffar brons ytor.
Den FE-modell som använts har nyligen validerats... (More)
Den här studien har utförts på en bro i Kiruna, i norra Sverige, som användes till gruvindustrin. En modell av bron skapades med finita elementmetoden i programvaran Abaqus 6.14 för att ta reda på huruvida temperatur- och töjningsvariationerna på bron på grund av klimatets påverkan kan beskrivas.
Klimatets temperaturpåverkan på bron är komplex. Under dagtid påverkas bron av strålning från solen och luftens temperatur som är relativt hög under den tid som bron har studerats. Under natten sker en temperatursänkning i bron på grund av utgående långvågig strålning och den relativt låga lufttemperaturen. Temperaturen i bron påverkas även av konvektion som uppstår då vinden träffar brons ytor.
Den FE-modell som använts har nyligen validerats för tvådimensionella modeller vad gäller temperaturpåverkan. I detta examensarbete har temperaturvariationer i ett tvärsnitt av bron studerats genom en tvådimensionell modell som inkluderar överhäng och asfaltsbeläggning. Temperaturvariationerna studerades för Juni 2009, Augusti 2010 och en kortare tidsperiod under Juni 2014. Töjningspåverkan av bron har undersökts i en två-dimensionell och en tre-dimensionell modell i Juni 2009.
FE-modellen beräknar temperaturvariationer inuti konstruktionen baserat på tillgänglig klimatdata, lufttemperatur, långvågig strålning och global strålning för en gång i timmen. Den klimatdata som använts har hämtats från Svenska Meteorologiska och Hydrologiska Institutet, SMHI, som är en institution med väderstationer över hela Sverige.
Temperaturens påverkan på bron leder med tiden till deformationer. Vid ökning av temperaturen tvingas betongen att expandera och en sänkning av temperaturen ger en motsatt effekt, det vill säga att betongen drar ihop sig. Deformationerna i konstruktionen påverkas även av hur stödförhållandena modelleras samt av materialegenskaperna.
Efter beräkning av temperaturvariationerna är det möjligt att beräkna deformationerna baserat på resultaten från temperaturberäkningen. Temperatur- och deformationsresultaten jämförs sedan med mätningar som utförts med hjälp av temperaturmätare och töjningsmätare av M.Sc. Niklas Bagge och hans medarbetare vid Luleås tekniska universitet.
Resultaten visar att 2D-temperaturmodellen beräknar temperaturvariationer som stämmer väldigt bra ihop med de verkliga temperaturvariationerna. Resultaten från 3D-töjningsmodellen visar att töjningsvariationerna kan fångas relativt bra medan resultaten från 2D-töjningsmodellen stämmer mindre bra överens med den verkliga variationen. (Less)
Please use this url to cite or link to this publication:
author
Fabricius, Mikael LU and Ekman, Henrik
supervisor
organization
alternative title
Modellering av temperaturvariationer och respons i Gruvvägsbron i Kiruna
course
VBK920 20161
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
CLIMATE, TEMPERATURE, FINITE ELEMENT, DEFORMATIONS, KIRUNA, SMHI, BRIDGE, STRAINS
publication/series
TVBK-5255
report number
TVBK-5255
ISSN
0349-4969
language
English
additional info
Examinator: Miklos Molnar
id
8889164
date added to LUP
2016-08-25 10:01:56
date last changed
2016-08-25 10:01:56
@misc{8889164,
  abstract     = {This thesis treats a concrete bridge located in Kiruna, in the north of Sweden, which was used for the mining industry. A finite element model has been created with the finite element software Abaqus to find out if it accurately can describe the variation of the temperature and deformation within the bridge over time. The temperature variations and deformations have been studied with respect to climate effects. 
The climate is complex and affects the temperature within the bridge in different ways. During daytime the bridge is exposed to radiation from the sun and the air temperature which is relatively high during the studied time period. During the night the bridge will cool down due to outgoing longwave radiation and the absence of the sun. The temperature in the bridge is also affected by convection mainly caused by wind.
The used finite element model has previously been verified for two-dimensional temperature variation in concrete structures without overhangs. In this work the temperature variation will be studied in a cross section of the bridge using a two-dimensional model including overhang and paving layer. The temperature variation was studied for June 2009, August 2010, and a short period during June 2014. The strain was studied in a three dimensional model for June 2009.
The finite element model calculates the temperature variations within a structure based on climate input data. This data consists of hourly values of air temperature, long wave radiation and global radiation. The temperature input data was received from the Swedish Meteorological and Hydrological Institute which have weather stations placed across Sweden.
The temperature variations lead to deformations. An increase in temperature will force the concrete to expand, and a decrease in temperature will force the concrete to contract. The modelled deformations within the structure are also affected by how the supports are modelled and the choice of material properties.
After calculating the temperature variations it is possible to calculate the deformations based on the temperature calculation results. The temperature- and deformation results were compared to measurements from temperature and strain gauges by M.Sc. Niklas Bagge and his co-workers from Luleå Technical University.
The results show that the 2D temperature model captures the temperature variation very well. Further the results show that the 3D strain model captures the strain variation fairly well and the 2D strain model shows unreliable results.},
  author       = {Fabricius, Mikael and Ekman, Henrik},
  issn         = {0349-4969},
  keyword      = {CLIMATE,TEMPERATURE,FINITE ELEMENT,DEFORMATIONS,KIRUNA,SMHI,BRIDGE,STRAINS},
  language     = {eng},
  note         = {Student Paper},
  series       = {TVBK-5255},
  title        = {Modeling of temperature variations and response in a mining road bridge in Kiruna},
  year         = {2016},
}