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Comparison of Models for Design of Portal Frame Bridges with regard to Restraint Forces

Gottsäter, Erik LU ; Larsson Ivanov, Oskar LU ; Crocetti, Roberto LU ; Molnár, Miklós LU and Plos, Mario (2017) Structures Congress 2017 In Structures Congress 2017: Bridges and Transportation Structures p.326-339
Abstract
In the design of concrete bridges an important aspect is limiting crack widths, since large cracks can lead to e.g. corrosion and affect the bridge functionality. Restraint forces caused by thermal loads and shrinkage will likely constitute a large part of the total forces acting on the bridge in crack width design. In this paper, restraint stresses in portal frame bridges are calculated according to Eurocode with simple hand calculation models, 2D frame models and linear elastic 3D FE-models. The results are then compared and used in Eurocode crack width design methods. Large tensile restraint stresses were found in the transverse direction close to the frame corners, and the required reinforcement amount significantly exceeded the... (More)
In the design of concrete bridges an important aspect is limiting crack widths, since large cracks can lead to e.g. corrosion and affect the bridge functionality. Restraint forces caused by thermal loads and shrinkage will likely constitute a large part of the total forces acting on the bridge in crack width design. In this paper, restraint stresses in portal frame bridges are calculated according to Eurocode with simple hand calculation models, 2D frame models and linear elastic 3D FE-models. The results are then compared and used in Eurocode crack width design methods. Large tensile restraint stresses were found in the transverse direction close to the frame corners, and the required reinforcement amount significantly exceeded the minimum reinforcement prescribed by codes. The results are however unrealistic since the thermal load distribution is simplified, and the crack width formula does not take the reduction of restraint stresses due to cracking into account. Future studies shall therefore determine a more realistic thermal load distribution and the effects of cracking, in order to create a more accurate linear elastic 3D FE design method. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
Structures Congress 2017: Bridges and Transportation Structures
pages
326 - 339
publisher
American Society of Civil Engineers (ASCE)
conference name
Structures Congress 2017
external identifiers
  • scopus:85019100920
ISBN
978-0-7844-8040-3
DOI
10.1061/9780784480403.028
language
English
LU publication?
yes
id
b05603c9-4d94-4ac5-9d77-d4a2f2d7afa8
date added to LUP
2017-04-21 15:24:44
date last changed
2018-01-07 12:00:26
@inproceedings{b05603c9-4d94-4ac5-9d77-d4a2f2d7afa8,
  abstract     = {In the design of concrete bridges an important aspect is limiting crack widths, since large cracks can lead to e.g. corrosion and affect the bridge functionality. Restraint forces caused by thermal loads and shrinkage will likely constitute a large part of the total forces acting on the bridge in crack width design. In this paper, restraint stresses in portal frame bridges are calculated according to Eurocode with simple hand calculation models, 2D frame models and linear elastic 3D FE-models. The results are then compared and used in Eurocode crack width design methods. Large tensile restraint stresses were found in the transverse direction close to the frame corners, and the required reinforcement amount significantly exceeded the minimum reinforcement prescribed by codes. The results are however unrealistic since the thermal load distribution is simplified, and the crack width formula does not take the reduction of restraint stresses due to cracking into account. Future studies shall therefore determine a more realistic thermal load distribution and the effects of cracking, in order to create a more accurate linear elastic 3D FE design method.},
  author       = {Gottsäter, Erik and Larsson Ivanov, Oskar and Crocetti, Roberto and Molnár, Miklós and Plos, Mario},
  booktitle    = {Structures Congress 2017: Bridges and Transportation Structures },
  isbn         = {978-0-7844-8040-3},
  language     = {eng},
  month        = {04},
  pages        = {326--339},
  publisher    = {American Society of Civil Engineers (ASCE)},
  title        = {Comparison of Models for Design of Portal Frame Bridges with regard to Restraint Forces},
  url          = {http://dx.doi.org/10.1061/9780784480403.028},
  year         = {2017},
}