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dc.contributor.authorNuttayasakul, Nuthapornen_US
dc.date.accessioned2014-03-14T20:19:17Z
dc.date.available2014-03-14T20:19:17Z
dc.date.issued2005-11-03en_US
dc.identifier.otheretd-11282005-010902en_US
dc.identifier.urihttp://hdl.handle.net/10919/29765
dc.description.abstractCold-formed steel roof truss systems that use complex stiffener patterns in existing hat shape members for both top and bottom chord elements are a growing trend in the North American steel framing industry. When designing cold-formed steel sections, a structural engineer typically tries to improve the local buckling behavior of the cold-formed steel elements. The complex hat shape has proved to limit the negative influence of local buckling, however, distortional buckling can be the controlling mode of failure in the design of chord members with intermediate unbraced lengths. The chord member may be subjected to both bending and compression because of the continuity of the top and bottom chords. These members are not typically braced between panel points in a truss. Current 2001 North American Specifications (NAS 2001) do not provide an explicit check for distortional buckling. This dissertation focuses on the behavior of complex hat shape members commonly used for both the top and bottom chord elements of a cold-formed steel truss. The results of flexural tests of complex hat shape members are described. In addition, stub column tests of nested C-sections used as web members and full scale cold-formed steel roof truss tests are reported. Numerical analyses using finite strip and finite element procedures were developed for the complex hat shape chord member in bending to compare with experimental results. Both elastic buckling and inelastic postbuckling finite element analyses were performed. A parametric study was also conducted to investigate the factors that affect the ultimate strength behavior of a particular complex hat shape. The experimental results and numerical analyses confirmed that modifications to the 2001 North American Specification are necessary to better predict the flexural strength of complex hat shape members, especially those members subjected to distortional buckling. Either finite strip or finite element analysis can be used to better predict the flexural strength of complex hat shape members. Better understanding of the flexural behavior of these complex hat shapes is necessary to obtain efficient, safe design of a truss system. The results of these analyses will be presented in the dissertation.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartETD.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectcold-formed steelen_US
dc.subjectelemental testen_US
dc.subjectfull scale testen_US
dc.subjectstub column testen_US
dc.subjectflexural testen_US
dc.subjectdistortional bucklingen_US
dc.subjectlocal bucklingen_US
dc.titleExperimental and Analytical Studies of the Behavior of Cold-Formed Steel Roof Truss Elementsen_US
dc.typeDissertationen_US
dc.contributor.departmentCivil Engineeringen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineCivil Engineeringen_US
dc.contributor.committeechairEasterling, William Samuelen_US
dc.contributor.committeememberRoberts-Wollmann, Carin L.en_US
dc.contributor.committeememberMurray, Thomas M.en_US
dc.contributor.committeememberCharney, Finley A.en_US
dc.contributor.committeememberSetareh, Mehdien_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11282005-010902/en_US
dc.date.sdate2005-11-28en_US
dc.date.rdate2005-12-01
dc.date.adate2005-12-01en_US


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