Degree Type

Dissertation

Date of Award

2016

Degree Name

Doctor of Philosophy

Department

Civil, Construction, and Environmental Engineering

Major

Civil Engineering

First Advisor

Jay Shen

Abstract

Concentrically braced frames (CBFs) have become one of the most commonly used lateral force resisting systems in seismic regions after the 1994 Northridge Earthquake due to the unexpected damages observed in moment frames. Diagonal bracing members in ductile CBFs are designed as primary seismic energy dissipating mechanisms so that structural damage can be limited with bracings. Thus, overall structural performance in ductile CBFs can be associated with plastic deformation capability of the bracing members. In this regard, local buckling-induced premature fracture and unsymmetrical hysteretic behavior of conventional buckling braces raise concerns about the seismic performance of CBFs. Buckling-restrained braces (BRBs), when properly designed, can be effective in terms of overcoming many potential issues caused by the nature of conventional bracings. Nevertheless, some aspects of the current BRBs limit wide-spread application of these braces. The vast majority of the BRB designs developed to date are costly, heavy and unnecessarily complicated. Further, the previous research on BRBs lacked discussing the performance goals and simplicity parallel to each other, which resulted in impractical designs for engineering applications in terms of constructability. The present study aims at developing steel brace models that are simple, practical and cost-effective by reducing the high labor and fabrication cost, avoiding the complicated cross-sections and connections, as well as enhancing fracture life of the braces without altering the current habits formed in the design practice so far. For this purpose, three innovative brace models for new design and enhancing the performance of existing structures are developed and examined by means of numerical and experimental studies. The results point out that the developed brace models are promising and capable of exhibiting symmetrical and stable inelastic cyclic response along with mitigating the possibility of brace fracture substantially. Further, the findings presented in this study expand the previous work in the literature by providing a framework for future studies.

Copyright Owner

Onur Seker

Language

en

File Format

application/pdf

File Size

230 pages

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