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Bro med huvudbalkar av stål och brobaneplatta av limträ

Israelsson, Björn LU (2012) VBK920 20121
Civil Engineering
Division of Structural Engingeering
Abstract
In this thesis a bridge with main girders of steel and a bridge deck made out of glulam is studied. The bridge is compared with an existing composite bridge built in Kalix, Sweden. Initially both bridge solutions are presented and some detail descriptions is presented for the bridge with the glulam deck. A short description of the finite element method is given together with the main equations for the finite element model for plates. The basics on how to build up a finite element model in SAP 2000 is also presented. A main goal with this report is to study how the risk for lateral torsional buckling can be reduced by using a lighter bridge deck. This is done by first deciding what kind of loads the bridge is subjected to. Then the critical... (More)
In this thesis a bridge with main girders of steel and a bridge deck made out of glulam is studied. The bridge is compared with an existing composite bridge built in Kalix, Sweden. Initially both bridge solutions are presented and some detail descriptions is presented for the bridge with the glulam deck. A short description of the finite element method is given together with the main equations for the finite element model for plates. The basics on how to build up a finite element model in SAP 2000 is also presented. A main goal with this report is to study how the risk for lateral torsional buckling can be reduced by using a lighter bridge deck. This is done by first deciding what kind of loads the bridge is subjected to. Then the critical lateral torsional buckling moment is calculated for different spacing between the cross girders. Hand calculations are compared to a finite element model in SAP 2000 and the minimum number of cross girders is calculated. The results are then compared with a finite element model in SAP 2000. It´s also checked how the risk for lateral torsional buckling is reduced when the bridge deck is attached. This is performed by attaching springs between main girders and bridge deck in the model in SAP 2000. The springs represent screws and different stiffness is applied to these screws. Analysis is made and the total stiffness of the bridge is examined. The bridge is also checked in the serviceability state. It is shown that the vertical deflection is
bigger than accepted. A suggestion to decrease the deflection is to build the bridge with a small vertical curvature. Results from the analysis shows that the number of cross girders can be reduced by half. It is
also shown that a distance of 160 mm is required between the screws with a diameter of 12 mm to achieve sufficient total stiffness of the bridge deck. This is the screws that attach the main girders to the bridge deck.
In the report an overviewing economic calculation is also done. The report shows that a big cost in the glulam alternatives is the bridge deck. However the alternatives with the glulam deck can be built faster since there is no time for concrete hardening. This can save a lot of
money in labor costs. (Less)
Please use this url to cite or link to this publication:
author
Israelsson, Björn LU
supervisor
organization
course
VBK920 20121
year
type
H3 - Professional qualifications (4 Years - )
subject
keywords
Samverkansbro, vippning, finita elementanalys, SAP 2000, brottgränstillstånd, bruksgränstillstånd, skjuvbuckling, spänningskapacitet
report number
TVBK-5213
ISSN
0349-4969
language
Swedish
id
3132377
date added to LUP
2012-10-24 14:55:44
date last changed
2012-12-13 10:05:59
@misc{3132377,
  abstract     = {In this thesis a bridge with main girders of steel and a bridge deck made out of glulam is studied. The bridge is compared with an existing composite bridge built in Kalix, Sweden. Initially both bridge solutions are presented and some detail descriptions is presented for the bridge with the glulam deck. A short description of the finite element method is given together with the main equations for the finite element model for plates. The basics on how to build up a finite element model in SAP 2000 is also presented. A main goal with this report is to study how the risk for lateral torsional buckling can be reduced by using a lighter bridge deck. This is done by first deciding what kind of loads the bridge is subjected to. Then the critical lateral torsional buckling moment is calculated for different spacing between the cross girders. Hand calculations are compared to a finite element model in SAP 2000 and the minimum number of cross girders is calculated. The results are then compared with a finite element model in SAP 2000. It´s also checked how the risk for lateral torsional buckling is reduced when the bridge deck is attached. This is performed by attaching springs between main girders and bridge deck in the model in SAP 2000. The springs represent screws and different stiffness is applied to these screws. Analysis is made and the total stiffness of the bridge is examined. The bridge is also checked in the serviceability state. It is shown that the vertical deflection is
bigger than accepted. A suggestion to decrease the deflection is to build the bridge with a small vertical curvature. Results from the analysis shows that the number of cross girders can be reduced by half. It is
also shown that a distance of 160 mm is required between the screws with a diameter of 12 mm to achieve sufficient total stiffness of the bridge deck. This is the screws that attach the main girders to the bridge deck.
In the report an overviewing economic calculation is also done. The report shows that a big cost in the glulam alternatives is the bridge deck. However the alternatives with the glulam deck can be built faster since there is no time for concrete hardening. This can save a lot of
money in labor costs.},
  author       = {Israelsson, Björn},
  issn         = {0349-4969},
  keyword      = {Samverkansbro,vippning,finita elementanalys,SAP 2000,brottgränstillstånd,bruksgränstillstånd,skjuvbuckling,spänningskapacitet},
  language     = {swe},
  note         = {Student Paper},
  title        = {Bro med huvudbalkar av stål och brobaneplatta av limträ},
  year         = {2012},
}