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Effects of geometric imperfections on bracing performance of cross-beams during construction of composite bridges

Mehri, Hassan LU ; Crocetti, Roberto LU and A. Yura, Joseph (2017) In Journal of Bridge Engineering 22(1).
Abstract
Steel girders require stability controls for different construction stages before the lateral-torsional support from the concrete deck occurs. The load-carrying capacity of bridge girders and bracing forces generated in their bracings are sensitive greatly to the girders' initial imperfections in terms of both the magnitude and distribution along the span. Relatively little knowledge is available in this matter, however, and decisions on the "worst" shape of imperfections which gives a conservative resistance and/or maximizes the bracings forces is often not an easy task in practice. The present paper reports the test results in terms of the load-carrying capacities and bracing forces of a large-scale bridge of twin I-girder type in which... (More)
Steel girders require stability controls for different construction stages before the lateral-torsional support from the concrete deck occurs. The load-carrying capacity of bridge girders and bracing forces generated in their bracings are sensitive greatly to the girders' initial imperfections in terms of both the magnitude and distribution along the span. Relatively little knowledge is available in this matter, however, and decisions on the "worst" shape of imperfections which gives a conservative resistance and/or maximizes the bracings forces is often not an easy task in practice. The present paper reports the test results in terms of the load-carrying capacities and bracing forces of a large-scale bridge of twin I-girder type in which the location of the intermediate crossbeam was varied across the depth of the main girders. Moreover, extensive numerical investigations were performed to study the effects of some relevant shape of imperfections on both the load-carrying capacities of the studied bridges and the magnitude of bracing forces generated in the cross-beams that were involved. The test results showed that the load-carrying capacity of steel girders may exceed their lowest theoretical eigenvalue, this occurring due to the presence of initial imperfections. In the Finite Element analyses of the studied bridge cases that were performed, in some cases, the girders followed their shape of geometric imperfections and reached a load value which was greater than the lowest eigenvalue of the systems. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Bridge Engineering
volume
22
issue
1
publisher
American Society of Civil Engineers (ASCE)
ISSN
1943-5592
DOI
10.1061/(ASCE)BE.1943-5592.0000984
language
English
LU publication?
yes
id
365b8e22-a63c-4ff5-b062-ae5343467e5e
date added to LUP
2016-07-01 17:07:12
date last changed
2017-01-17 11:44:07
@article{365b8e22-a63c-4ff5-b062-ae5343467e5e,
  abstract     = {Steel girders require stability controls for different construction stages before the lateral-torsional support from the concrete deck occurs. The load-carrying capacity of bridge girders and bracing forces generated in their bracings are sensitive greatly to the girders' initial imperfections in terms of both the magnitude and distribution along the span. Relatively little knowledge is available in this matter, however, and decisions on the "worst" shape of imperfections which gives a conservative resistance and/or maximizes the bracings forces is often not an easy task in practice. The present paper reports the test results in terms of the load-carrying capacities and bracing forces of a large-scale bridge of twin I-girder type in which the location of the intermediate crossbeam was varied across the depth of the main girders. Moreover, extensive numerical investigations were performed to study the effects of some relevant shape of imperfections on both the load-carrying capacities of the studied bridges and the magnitude of bracing forces generated in the cross-beams that were involved. The test results showed that the load-carrying capacity of steel girders may exceed their lowest theoretical eigenvalue, this occurring due to the presence of initial imperfections. In the Finite Element analyses of the studied bridge cases that were performed, in some cases, the girders followed their shape of geometric imperfections and reached a load value which was greater than the lowest eigenvalue of the systems.},
  articleno    = {04016106},
  author       = {Mehri, Hassan and Crocetti, Roberto and A. Yura, Joseph},
  issn         = {1943-5592},
  language     = {eng},
  number       = {1},
  publisher    = {American Society of Civil Engineers (ASCE)},
  series       = {Journal of Bridge Engineering},
  title        = {Effects of geometric imperfections on bracing performance of cross-beams during construction of composite bridges},
  url          = {http://dx.doi.org/10.1061/(ASCE)BE.1943-5592.0000984},
  volume       = {22},
  year         = {2017},
}