Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading

Several investigations have shown that the ultimate resistance of plate girders subjected to patch loading is increased when a longitudinal stiffener is placed at the web panel of the steel girder. However, the influence of factors such as the patch loading length and the configuration of the longit...

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Autores:
Loaiza Ramones, Nelson Adolfo
Tipo de recurso:
Doctoral thesis
Fecha de publicación:
2019
Institución:
Universidad Nacional de Colombia
Repositorio:
Universidad Nacional de Colombia
Idioma:
spa
OAI Identifier:
oai:repositorio.unal.edu.co:unal/76326
Acceso en línea:
https://repositorio.unal.edu.co/handle/unal/76326
http://bdigital.unal.edu.co/72602/
Palabra clave:
Patch loading
Plate girders
Longitudinal stiffening
Elastic buckling
Numerical modelling
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openAccess
License
Atribución-NoComercial 4.0 Internacional
id UNACIONAL2_debd32bd13805b93f8bc848781f805ab
oai_identifier_str oai:repositorio.unal.edu.co:unal/76326
network_acronym_str UNACIONAL2
network_name_str Universidad Nacional de Colombia
repository_id_str
dc.title.spa.fl_str_mv Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
title Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
spellingShingle Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
Patch loading
Plate girders
Longitudinal stiffening
Elastic buckling
Numerical modelling
title_short Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
title_full Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
title_fullStr Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
title_full_unstemmed Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
title_sort Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading
dc.creator.fl_str_mv Loaiza Ramones, Nelson Adolfo
dc.contributor.advisor.spa.fl_str_mv Graciano Gallego, Carlos Alberto (Thesis advisor)
dc.contributor.author.spa.fl_str_mv Loaiza Ramones, Nelson Adolfo
dc.subject.proposal.spa.fl_str_mv Patch loading
Plate girders
Longitudinal stiffening
Elastic buckling
Numerical modelling
topic Patch loading
Plate girders
Longitudinal stiffening
Elastic buckling
Numerical modelling
description Several investigations have shown that the ultimate resistance of plate girders subjected to patch loading is increased when a longitudinal stiffener is placed at the web panel of the steel girder. However, the influence of factors such as the patch loading length and the configuration of the longitudinal stiffener has received little attention. Therefore, this thesis is aimed at studying the effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading. At first, the influence of the patch loading length on the critical buckling coefficient is investigated by means of linear finite element analysis. The effect of the panel aspect ratio, the position, and size of the longitudinal stiffener was also addressed. Additionally, the influence of a second stiffener located at the web panel was studied (multiple stiffening). Results indicate that buckling coefficients increment when the patch loading length is increased. Currently, in the Eurocode 3 Part 1-5 the ultimate resistance of girders subjected to patch loading is obtained by calculating the slenderness parameter, a dimensionless factor that depends on the yield resistance and the critical buckling load. The critical load which expression is derived from numerical modelling shows that critical load rises with an increasing distance between the stiffener and the loaded flange. However, at ultimate load level experiments had shown that ultimate resistance rises when the longitudinal stiffener is placed near the loaded flange. With the purpose of obtaining the same behavior described at ultimate load level, new hypothesis of boundary restrictions at the stiffener location are presented to model the elastic buckling behavior of webs subjected to patch loading. From these results a new approach that corrects the calculation of the slenderness parameter and harmonize the behavior between critical load and ultimate load level is proposed. The last edition of the AISC Specifications presents a formulation to calculate the ultimate resistance of unstiffened girders subjected to patch loading. This formulation is based on a four plastic hinges mechanism that considers crippling effect produced in the web panel of slender girders. Considering that the flange-to-web yield strength ratio has no influence on the ultimate resistance for hybrid girders subjected to patch loading, a closed-form solution to predict the ultimate resistance for stiffened girders is proposed by modifying a previously developed mechanism. International code provisions suggest use a longitudinal stiffener at one-fifth of the girder height as the best position for flexural resistance (b1 =0.20hw), nevertheless results indicate that the optimum position to increase the ultimate resistance of a girder subjected to patch loading is different (b1 0.20hw). It has also been demonstrated that when the slenderness of the directly loaded panel b1/tw decreases the ultimate resistance increases. Since bending governs the in-service girders behavior, a check for steel bridges girders erected by incremental launching was performed using nonlinear finite element analysis. In this case two strategies to study the impact of the slenderness ratio b1/tw on the ultimate resistance were evaluated, the first by changing the web thickness tw while maintaining the stiffener at b1 =0.20hw, and the second by changing the position of the stiffener b1 for various web thicknesses. Results show that the contribution of a stiffener placed at b1 =0.20hw is only significant for thinner webs. Finally, the results derived from the theoretical predictions are compared against the test experimental results available in the literature, in order to discuss the goodness and limitations of the approaches developed herein.
publishDate 2019
dc.date.issued.spa.fl_str_mv 2019-06
dc.date.accessioned.spa.fl_str_mv 2020-03-30T06:18:13Z
dc.date.available.spa.fl_str_mv 2020-03-30T06:18:13Z
dc.type.spa.fl_str_mv Trabajo de grado - Doctorado
dc.type.driver.spa.fl_str_mv info:eu-repo/semantics/doctoralThesis
dc.type.version.spa.fl_str_mv info:eu-repo/semantics/acceptedVersion
dc.type.coar.spa.fl_str_mv http://purl.org/coar/resource_type/c_db06
dc.type.content.spa.fl_str_mv Text
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dc.identifier.uri.none.fl_str_mv https://repositorio.unal.edu.co/handle/unal/76326
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url https://repositorio.unal.edu.co/handle/unal/76326
http://bdigital.unal.edu.co/72602/
dc.language.iso.spa.fl_str_mv spa
language spa
dc.relation.ispartof.spa.fl_str_mv Universidad Nacional de Colombia Sede Medellín Facultad de Minas Escuela de Ingeniería Civil
Escuela de Ingeniería Civil
dc.relation.haspart.spa.fl_str_mv 62 Ingeniería y operaciones afines / Engineering
69 Construcción / Building and construction
dc.relation.references.spa.fl_str_mv Loaiza Ramones, Nelson Adolfo (2019) Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading. Doctorado thesis, Universidad Nacional de Colombia - Sede Medellín.
dc.rights.spa.fl_str_mv Derechos reservados - Universidad Nacional de Colombia
dc.rights.coar.fl_str_mv http://purl.org/coar/access_right/c_abf2
dc.rights.license.spa.fl_str_mv Atribución-NoComercial 4.0 Internacional
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dc.rights.accessrights.spa.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv Atribución-NoComercial 4.0 Internacional
Derechos reservados - Universidad Nacional de Colombia
http://creativecommons.org/licenses/by-nc/4.0/
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spelling Atribución-NoComercial 4.0 InternacionalDerechos reservados - Universidad Nacional de Colombiahttp://creativecommons.org/licenses/by-nc/4.0/info:eu-repo/semantics/openAccesshttp://purl.org/coar/access_right/c_abf2Graciano Gallego, Carlos Alberto (Thesis advisor)a02bcbf9-0d60-44ea-9dee-2f397046905c-1Loaiza Ramones, Nelson Adolfoe381c5d7-feba-4394-a42a-f4824df289d83002020-03-30T06:18:13Z2020-03-30T06:18:13Z2019-06https://repositorio.unal.edu.co/handle/unal/76326http://bdigital.unal.edu.co/72602/Several investigations have shown that the ultimate resistance of plate girders subjected to patch loading is increased when a longitudinal stiffener is placed at the web panel of the steel girder. However, the influence of factors such as the patch loading length and the configuration of the longitudinal stiffener has received little attention. Therefore, this thesis is aimed at studying the effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading. At first, the influence of the patch loading length on the critical buckling coefficient is investigated by means of linear finite element analysis. The effect of the panel aspect ratio, the position, and size of the longitudinal stiffener was also addressed. Additionally, the influence of a second stiffener located at the web panel was studied (multiple stiffening). Results indicate that buckling coefficients increment when the patch loading length is increased. Currently, in the Eurocode 3 Part 1-5 the ultimate resistance of girders subjected to patch loading is obtained by calculating the slenderness parameter, a dimensionless factor that depends on the yield resistance and the critical buckling load. The critical load which expression is derived from numerical modelling shows that critical load rises with an increasing distance between the stiffener and the loaded flange. However, at ultimate load level experiments had shown that ultimate resistance rises when the longitudinal stiffener is placed near the loaded flange. With the purpose of obtaining the same behavior described at ultimate load level, new hypothesis of boundary restrictions at the stiffener location are presented to model the elastic buckling behavior of webs subjected to patch loading. From these results a new approach that corrects the calculation of the slenderness parameter and harmonize the behavior between critical load and ultimate load level is proposed. The last edition of the AISC Specifications presents a formulation to calculate the ultimate resistance of unstiffened girders subjected to patch loading. This formulation is based on a four plastic hinges mechanism that considers crippling effect produced in the web panel of slender girders. Considering that the flange-to-web yield strength ratio has no influence on the ultimate resistance for hybrid girders subjected to patch loading, a closed-form solution to predict the ultimate resistance for stiffened girders is proposed by modifying a previously developed mechanism. International code provisions suggest use a longitudinal stiffener at one-fifth of the girder height as the best position for flexural resistance (b1 =0.20hw), nevertheless results indicate that the optimum position to increase the ultimate resistance of a girder subjected to patch loading is different (b1 0.20hw). It has also been demonstrated that when the slenderness of the directly loaded panel b1/tw decreases the ultimate resistance increases. Since bending governs the in-service girders behavior, a check for steel bridges girders erected by incremental launching was performed using nonlinear finite element analysis. In this case two strategies to study the impact of the slenderness ratio b1/tw on the ultimate resistance were evaluated, the first by changing the web thickness tw while maintaining the stiffener at b1 =0.20hw, and the second by changing the position of the stiffener b1 for various web thicknesses. Results show that the contribution of a stiffener placed at b1 =0.20hw is only significant for thinner webs. Finally, the results derived from the theoretical predictions are compared against the test experimental results available in the literature, in order to discuss the goodness and limitations of the approaches developed herein.Doctoradoapplication/pdfspaUniversidad Nacional de Colombia Sede Medellín Facultad de Minas Escuela de Ingeniería CivilEscuela de Ingeniería Civil62 Ingeniería y operaciones afines / Engineering69 Construcción / Building and constructionLoaiza Ramones, Nelson Adolfo (2019) Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loading. Doctorado thesis, Universidad Nacional de Colombia - Sede Medellín.Effect of longitudinal stiffening on the ultimate resistance of plate girders subjected to patch loadingTrabajo de grado - Doctoradoinfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/acceptedVersionhttp://purl.org/coar/resource_type/c_db06Texthttp://purl.org/redcol/resource_type/TDPatch loadingPlate girdersLongitudinal stiffeningElastic bucklingNumerical modellingORIGINAL100204539.2019.pdfTesis de Doctorado en Ingeniería - Ingeniería Civilapplication/pdf3145705https://repositorio.unal.edu.co/bitstream/unal/76326/1/100204539.2019.pdfe44065b4fec9d9e32a3ba94e31bd31e8MD51THUMBNAIL100204539.2019.pdf.jpg100204539.2019.pdf.jpgGenerated Thumbnailimage/jpeg4562https://repositorio.unal.edu.co/bitstream/unal/76326/2/100204539.2019.pdf.jpgb31cce3cad282ef54ea7d0af1acf6a42MD52unal/76326oai:repositorio.unal.edu.co:unal/763262023-07-28 10:58:56.039Repositorio Institucional Universidad Nacional de Colombiarepositorio_nal@unal.edu.co