Use of Cast Modular Components for Concentrically Braced Steel Frames

Persistent Link:
http://hdl.handle.net/10150/268572
Title:
Use of Cast Modular Components for Concentrically Braced Steel Frames
Author:
Federico, Giovanni
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Cast modular components have been under development for earthquake resistant steel structures. These concepts take advantage of the versatility in geometry afforded with the casting process to create components specifically configured for ductile behavior. Two systems were developed as part of this dissertation research: (1) the Cast Modular Ductile Bracing system (CMDB); (2) the Floating Brace system (FB).The CMDB system makes use of cast components introduced at the ends and the center of the brace to produce a special bracing detail with reliable strength, stiffness and deformation capacity. The system takes advantage of the versatility in geometry offered by the casting process to create configurations that eliminate non-ductile failure modes in favor of stable inelastic deformation capacity. This thesis presents analytical research performed to determine the buckling strength and buckling direction of the bracing element based on the geometries of the cast components. Limiting geometries are determined for the cast components to control the buckling direction. Design formulas for buckling strength are proposed. The Floating Brace system is a new lateral bracing concept developed for steel special concentric braced frames. The concept uses a set of special plate details at the end of the brace to create a stiff, strong and ductile lateral bracing system. The plates are arranged such that some provide direct axial support for high initial stiffness and elimination of fatigue issues for daily service wind loads. The remaining plates are oriented transverse to the brace and thus provide ductile bending response for the rare earthquake event, in which the axial plates become sacrificial. The main bracing member and cast pieces remain elastic or nearly elastic. Thus, following the seismic event, the plates can be replaced. In this thesis, analytical studies using nonlinear finite element analysis are performed to determine the optimum: (a) relative strength of the end connection to the brace; and (b) ratio of strength between axial and transverse plates. Design equations are provided. Prototypes for each concept were developed. Castings were created. Large scale laboratory physical testing was performed as experimental verification (proof of concept) for the two systems.
Type:
text; Electronic Dissertation
Keywords:
seismic design; Civil Engineering; castings; Concentrically braced steel frame
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Civil Engineering
Degree Grantor:
University of Arizona
Advisor:
Fleischman, Robert B.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleUse of Cast Modular Components for Concentrically Braced Steel Framesen_US
dc.creatorFederico, Giovannien_US
dc.contributor.authorFederico, Giovannien_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractCast modular components have been under development for earthquake resistant steel structures. These concepts take advantage of the versatility in geometry afforded with the casting process to create components specifically configured for ductile behavior. Two systems were developed as part of this dissertation research: (1) the Cast Modular Ductile Bracing system (CMDB); (2) the Floating Brace system (FB).The CMDB system makes use of cast components introduced at the ends and the center of the brace to produce a special bracing detail with reliable strength, stiffness and deformation capacity. The system takes advantage of the versatility in geometry offered by the casting process to create configurations that eliminate non-ductile failure modes in favor of stable inelastic deformation capacity. This thesis presents analytical research performed to determine the buckling strength and buckling direction of the bracing element based on the geometries of the cast components. Limiting geometries are determined for the cast components to control the buckling direction. Design formulas for buckling strength are proposed. The Floating Brace system is a new lateral bracing concept developed for steel special concentric braced frames. The concept uses a set of special plate details at the end of the brace to create a stiff, strong and ductile lateral bracing system. The plates are arranged such that some provide direct axial support for high initial stiffness and elimination of fatigue issues for daily service wind loads. The remaining plates are oriented transverse to the brace and thus provide ductile bending response for the rare earthquake event, in which the axial plates become sacrificial. The main bracing member and cast pieces remain elastic or nearly elastic. Thus, following the seismic event, the plates can be replaced. In this thesis, analytical studies using nonlinear finite element analysis are performed to determine the optimum: (a) relative strength of the end connection to the brace; and (b) ratio of strength between axial and transverse plates. Design equations are provided. Prototypes for each concept were developed. Castings were created. Large scale laboratory physical testing was performed as experimental verification (proof of concept) for the two systems.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectseismic designen_US
dc.subjectCivil Engineeringen_US
dc.subjectcastingsen_US
dc.subjectConcentrically braced steel frameen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineCivil Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFleischman, Robert B.en_US
dc.contributor.committeememberHaldar, Achintyaen_US
dc.contributor.committeememberRichard, Ralph M.en_US
dc.contributor.committeememberFleischman, Robert B.en_US
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