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Evaluation of seismic action in Sweden using the European Seismic Hazard Model

Larsson, Erik LU and Magnusson, Lucas LU (2017) In TVSM-5000 VSM820 20171
Structural Mechanics
Department of Construction Sciences
Abstract
In 2013 the European Seismic Hazard Model 2013 (ESHM13) was released as a result of the EU-funded project Seismic Harmonization in Europe (SHARE). This hazard model provides seismic data applicable for structural engineering for every location in Europe and Turkey that directly correlates to the seismic regulations provided by Eurocode 8. Currently, earthquake engineering according to Eurocode is not standard procedure for structures in Sweden due to the low regional seismicity. The objective of this thesis is to employ the data from ESHM13 and evaluate if there is reason to consider earthquakes in relation to building construction in Sweden. Specifically, the response from seismic loads for buildings of normal importance (e.g. apartment... (More)
In 2013 the European Seismic Hazard Model 2013 (ESHM13) was released as a result of the EU-funded project Seismic Harmonization in Europe (SHARE). This hazard model provides seismic data applicable for structural engineering for every location in Europe and Turkey that directly correlates to the seismic regulations provided by Eurocode 8. Currently, earthquake engineering according to Eurocode is not standard procedure for structures in Sweden due to the low regional seismicity. The objective of this thesis is to employ the data from ESHM13 and evaluate if there is reason to consider earthquakes in relation to building construction in Sweden. Specifically, the response from seismic loads for buildings of normal importance (e.g. apartment buildings) and building of vital importance (e.g. hospitals) were examined.

Eurocode 8 states that buildings of normal importance should be designed for an earthquake with a return period of 475 years. The way to differentiate building in terms of reliabilities in Eurocode 8 is to scale the reference seismic action for buildings of ordinary importance with a factor depending on importance class. This factor is a nationally determined parameter, and since these are absent in the Swedish annex it was shown that the recommended factor approximately correlates to an implicit return period of 1300 years for buildings of vital importance.

With the use of hazard data for Lund, modal response spectrum analyses were carried out on simple 2D models and a more complex 3D FE-model. The results were compared to static analyses on the same models using the wind load as comparative action. From parametric studies, that varies a range of levels and stiffnesses, the resulting base response was compared between wind load and seismic load. Spectra with return periods correlating to 475- and 1300-year were used. An additional case study was carried out on a five story building, comparing sectional forces in a shear wall due to seismic loads and wind loads. The parametric studies clearly showed that the base response when using a 1300-year spectrum envelopes the base response from the wind load for almost every single parameter. In some cases, even a 475-year spectrum gives a higher response compared to the
wind. Since the seismic response is mass-dependent and the wind response is surfacedependent, it was shown that the 475-year spectrum could easily envelope the wind for elongated building when analyzed in the long direction.

The comparison of the sectional forces in the case study suggests that the base response is a relevant measure when the overall response is compared for seismic load and wind load. However, it was shown that the seismic response is not necessarily largest at its
base which suggests that the critical findings in the parametric study are potentially on the non-conservative side. (Less)
Popular Abstract (Swedish)
Jordbävningar i Sverige är ovanliga, så pass att dimensionering för seismisk last inte sker i Sverige med undantag för speciella byggnader såsom kärnkraftverk. Jordbävningsdimensionering regleras av Eurokod 8 och Boverket har i den svenska bilagan beslutat att inte utge föreskrifter eller allmänna råd avseende användningen av koden eftersom den torde komma till användning i Sverige enbart i mycket särskilda fall. Detta är en seismisk riskutvärdering som inte står i linje med t.ex. Norge som har infört Eurokod 8 och slutsatsen är således att den seismiska faran har bedömts vara värre på andra sidan landsgränsen, vilket såklart inte är logiskt.
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author
Larsson, Erik LU and Magnusson, Lucas LU
supervisor
organization
course
VSM820 20171
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
SHARE, ESHM13, Modal Response Spectrum Analysis, Linear Dynamics.
publication/series
TVSM-5000
report number
TVSM-5226
ISSN
0281-6679
language
English
id
8927026
alternative location
http://www.byggmek.lth.se/english/publications/#0
date added to LUP
2017-10-11 10:14:53
date last changed
2017-10-11 10:14:53
@misc{8927026,
  abstract     = {In 2013 the European Seismic Hazard Model 2013 (ESHM13) was released as a result of the EU-funded project Seismic Harmonization in Europe (SHARE). This hazard model provides seismic data applicable for structural engineering for every location in Europe and Turkey that directly correlates to the seismic regulations provided by Eurocode 8. Currently, earthquake engineering according to Eurocode is not standard procedure for structures in Sweden due to the low regional seismicity. The objective of this thesis is to employ the data from ESHM13 and evaluate if there is reason to consider earthquakes in relation to building construction in Sweden. Specifically, the response from seismic loads for buildings of normal importance (e.g. apartment buildings) and building of vital importance (e.g. hospitals) were examined.

Eurocode 8 states that buildings of normal importance should be designed for an earthquake with a return period of 475 years. The way to differentiate building in terms of reliabilities in Eurocode 8 is to scale the reference seismic action for buildings of ordinary importance with a factor depending on importance class. This factor is a nationally determined parameter, and since these are absent in the Swedish annex it was shown that the recommended factor approximately correlates to an implicit return period of 1300 years for buildings of vital importance.

With the use of hazard data for Lund, modal response spectrum analyses were carried out on simple 2D models and a more complex 3D FE-model. The results were compared to static analyses on the same models using the wind load as comparative action. From parametric studies, that varies a range of levels and stiffnesses, the resulting base response was compared between wind load and seismic load. Spectra with return periods correlating to 475- and 1300-year were used. An additional case study was carried out on a five story building, comparing sectional forces in a shear wall due to seismic loads and wind loads. The parametric studies clearly showed that the base response when using a 1300-year spectrum envelopes the base response from the wind load for almost every single parameter. In some cases, even a 475-year spectrum gives a higher response compared to the
wind. Since the seismic response is mass-dependent and the wind response is surfacedependent, it was shown that the 475-year spectrum could easily envelope the wind for elongated building when analyzed in the long direction.

The comparison of the sectional forces in the case study suggests that the base response is a relevant measure when the overall response is compared for seismic load and wind load. However, it was shown that the seismic response is not necessarily largest at its
base which suggests that the critical findings in the parametric study are potentially on the non-conservative side.},
  author       = {Larsson, Erik and Magnusson, Lucas},
  issn         = {0281-6679},
  keyword      = {SHARE,ESHM13,Modal Response Spectrum Analysis,Linear Dynamics.},
  language     = {eng},
  note         = {Student Paper},
  series       = {TVSM-5000},
  title        = {Evaluation of seismic action in Sweden using the European Seismic Hazard Model},
  year         = {2017},
}