Numerical Assessment of LTB Resistance Equations of Aisc for Laterally Un-Restrained High Strength Steel I-Shaped Beams
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Department of Civil and Environmental Engineering(CEE), Islamic University of Technology(IUT), Board Bazar, Gazipur-1704, Bangladesh
Abstract
To date, numerous research studies have focused on examining the Lateral
Torsional Buckling (LTB) behavior of Normal Strength Steel (NSS) beams.
Consequently, the current design codes offer extensive guidance for
calculating the LTB strength of NSS beams. With the rising popularity of
High Strength Steel (HSS) (with a yield strength of fy ≥ 690 MPa or
approximately 100 ksi), many design standards now permit the use of HSS
up to grades of 690 MPa. However, the AISC 360-22 standard does not yet
support the use of HSS, as there is a shortage of sufficient experimental and
numerical studies needed to assess the LTB strength of HSS beams. This
research aims to numerically investigate the LTB strength of HSS I-shaped
beams under various moment gradients. A comprehensive three-dimensional
finite element (FE) model of HSS I-beams was created using ABAQUS,
incorporating both geometric and material nonlinearities. Since HSS has
distinct material and residual stress characteristics compared to NSS,
experimentally determined material properties and residual stress patterns
unique to HSS were included in the model. The FE model was first validated
against existing test results before being used to perform a parametric
evaluation. The parametric study considered a wide range of factors,
including steel grades, beam lengths, and both linear and non-linear moment
gradients, to determine the LTB strength of HSS beams. Finally, the
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numerical results obtained were compared with the LTB strength values
derived from the existing equations in AISC 360-22
Description
Supervised by
Supervised by
Dr. Md. Imran Kabir,
Assistant Professor,
Department of Civil and Environmental Engineering(CEE),
Islamic University of Technology(IUT),
Board Bazar, Gazipur-1704, Bangladesh.
This thesis is submitted in partial fulfillment of the requirements for the degree of Bachelor of Civil and Environmental Engineering, 2024
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Citation
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