Characterization of behavior of steel-concrete composite members and frames with applications for design

Denavit, Mark D.

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https://hdl.handle.net/2142/42420 Copy

Description

Title

Characterization of behavior of steel-concrete composite members and frames with applications for design

Author(s)

Denavit, Mark D.

Issue Date

2013-02-03T19:37:56Z

Director of Research (if dissertation) or Advisor (if thesis)

Hajjar, Jerome F.

Doctoral Committee Chair(s)

LaFave, James M.

Committee Member(s)

• Hajjar, Jerome F.
• Masud, Arif
• Leon, Roberto T.
• Fahnestock, Larry A.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Composite Construction
• Steel
• Concrete
• Nonlinear Analysis
• Load Transfer
• Stability
• Seismic

Abstract

Steel-concrete composite frames are seeing increased use in practice. Their excellent structural characteristics, including high strength, stiffness, and ductility, make them an appealing option for many building configurations. However, there exist gaps in the knowledge of behavior and the design provisions for these structures. This work seeks to document composite member and frame behavior and address key design issues through targeted studies utilizing advanced computational formulations and detailed examination of experimental results. A three-dimensional distributed plasticity beam finite element formulation suitable for nonlinear static and dynamic analyses of steel-concrete composite frames has been developed. The formulation is suitable for both concrete-filled steel tubes (CFT) and steel reinforced concrete (SRC) members, as well as steel wide-flange and hollow structural steel sections that are part of composite frames. A mixed basis for the formulation was chosen to allow for accurate modeling of both material and geometric nonlinearities. The formulation utilizes uniaxial cyclic constitutive relations for the concrete and steel that account for the salient features of each material, as well as the interaction between the two, including concrete confinement and local buckling. The accuracy of the formulation was verified against a wide variety of monotonic and cyclic experimental results of composite members, demonstrating the capability of the formulation to accurately produce realistic simulations of element and frame behavior. Aspects of the behavior of composite columns were assessed through an examination of results from a series of experiments on full-scale slender CFT beam-columns conducted by project collaborators. Additionally, comparative computational analyses were performed using the mixed beam formulation and detailed data interpretation focusing on the beam-column interaction strength was conducted. Several aspects of the design of steel-concrete composite structures were examined. The natural bond behavior of CFT columns was investigated through an examination of prior experimental work and new provisions were developed for the assessment of natural bond strength of CFT connections. The in-plane stability behavior of steel-concrete composite members and frames was assessed through a parametric study on small non-redundant benchmark frames, leading to the development of new elastic flexural rigidities for elastic analysis of composite members; new effective flexural rigidities for calculating the axial compressive strength of SRC members; new Direct Analysis stiffness reductions for composite members; and new recommendations for the construction of the interaction diagram for composite members. The seismic behavior of composite moment and braced frames was assessed through static pushover and incremental dynamic analyses. The analyses were performed on a suite of 60 archetype frames that were designed according to current design provisions. Connections were assumed to be strong; however, panel zone behavior for the moment frames and bond-slip behavior for SRC columns were included in the model. Using the analysis results, system performance factors were developed for the composite frames based on the methodology described in FEMA P695.

Graduation Semester

2012-12

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http://hdl.handle.net/2142/42420

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Copyright 2012 Mark D. Denavit

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