Cold-Formed Steel Behavior: Elastic Buckling Simplified Methods for Structural Members with Edge-Stiffened Holes and Purlin Distortional Buckling Strength Under Gravity Loading

dc.contributor.authorGrey, Christopher Nortonen
dc.contributor.committeechairMoen, Cristopher D.en
dc.contributor.committeememberEatherton, Matthew R.en
dc.contributor.committeememberWright, William J.en
dc.contributor.departmentStructural Engineering and Materialsen
dc.date.accessioned2014-03-14T20:37:02Zen
dc.date.adate2011-05-27en
dc.date.available2014-03-14T20:37:02Zen
dc.date.issued2011-04-29en
dc.date.rdate2011-05-27en
dc.date.sdate2011-05-15en
dc.description.abstractElastic Buckling Simplified Methods for Structural Members with Edge-Stiffened Holes: Presently, the current design methods available to engineers to predict the strength of cold-formed steel members with edge-stiffened holes remains largely unaddressed in the North American Specification for the Design of Cold-Formed Steel Structural Members (NAS). Research was conducted to explore and develop a further understanding of the effects of stiffened edge holes on the elastic buckling parameters for local, distortional, and global buckling. Elastic buckling parameter studies have been conducted on a suite of cold-formed members including recently developed DeltaSTUDs manufactured by Steelform Building Products, Inc. and a series of common Steel Stud Manufacturers Association (SSMA) members. Furthermore, a suite of simplified methods for determining elastic buckling parameters used to predict capacity with the Direct Strength Method (DSM) for members with edge stiffened holes were developed and validated. The elastic buckling studies are used to validate the simplified methods presented in this thesis. All simplified methods are further validated with thin shell finite element eigen-buckling parameter studies where the edge-stiffened holes are explicitly modeled. Purlin Distortional Buckling Strength Under Gravity Loading: Laterally braced cold-formed steel beams generally fail due to local and/or distortional buckling in combination with yielding. For many members, distortional buckling is the dominant buckling mode and is addressed in the current North American Specification for the Design of Cold-formed Steel Structural Members. The current main code equation, AISI C3.1.4-10 for calculating the available distortional buckling stress was derived experimentally based on a series of four-point bending tests at John Hopkins University. Where this provides a good basis for determining capacity, in most loading conditions purlins are subjected to a downward uniform loading that provides additional resistance to distortional buckling in the top flange beyond the resistance of the steel roofing panel. This research describes an experimental study to explore and quantify the difference in distortional buckling flexural capacity of metal building Z-purlins treated as isolated components and Z-purlins loaded with a constant pressure applied to metal roof panels. A series of three different types of tests have been developed to quantify the system effect provided by the metal roof panels as well as downward pressure on distortional buckling. Results are also extended to validate the Direct Strength Method when predicting flexural capacity of purlins in a roof system.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05152011-221433en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05152011-221433/en
dc.identifier.urihttp://hdl.handle.net/10919/32829en
dc.publisherVirginia Techen
dc.relation.haspartGrey_CN_T_2011.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectfinite strip methoden
dc.subjectdirect strength methoden
dc.subjectcomputational modelingen
dc.subjectfinite element solutionen
dc.titleCold-Formed Steel Behavior: Elastic Buckling Simplified Methods for Structural Members with Edge-Stiffened Holes and Purlin Distortional Buckling Strength Under Gravity Loadingen
dc.typeThesisen
thesis.degree.disciplineStructural Engineering and Materialsen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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