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05.38: Design procedure development of light gauge built‐up beam to ensuer yield bending strength: Antisymmetric bending moment
Author(s) -
Yoshimoto Shun,
Sato Atsushi
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.179
Subject(s) - structural engineering , beam (structure) , bending moment , stiffness , bending stiffness , antisymmetric relation , mechanism (biology) , buckling , moment (physics) , pure bending , engineering , bending , physics , classical mechanics , quantum mechanics , mathematical physics
American Iron and Steel Institute (AISI) stipulates a lateral force resisting system called CFS‐SBMF. In this system, built‐up beams are connected to hollow section columns by bolts to compose moment frame. Structural system proposed in previous study used built‐up beam in shape of rectangular section. Built‐up beams are composed by double channels toe‐to‐toe. When the beam is subjected to loads, 4 pattern of collapse mechanisms can be expected. 1) Yielding; 2) Lateral torsional buckling (LTB) of built‐up member; 3) LTB of individual channel between the connecting plates; 4) LTB of individual channel due to lack of the connecting plates stiffness and strength. Yielding, full capacity of the member, is expected in seismic design to maximize the performance of the structural system; therefore, it is necessary to prevent collapse mechanisms from No.2 to No.4. To prevent the collapse mechanism No.2, following shall be fulfilled. Assuming that the section of the beam is rectangular steel tubular member. Then the length of the beam will be checked with this length; it is fulfilled when the beam is shorter or equal to the computed allowable length. To prevent the collapse mechanism No.3, following numerical simulation shall be conducted to propose design procedure. Length between connecting plates is set as parameter; connecting location was distributed equally in the longitudinal direction of built‐up member. To prevent the collapse mechanism No.4, following design procedure is proposed. It was assumed that failure at the connecting plate, i.e., yielding, will not occur when it is designed to be stronger than the connected channel flange out‐of‐plane strength. Finally, design procedure that can prevent unexpected collapse modes was verified by numerical simulation. Proposed design procedure is applicable to design appropriate built‐up beam in an economical manner.