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11.27: Elastic buckling load and load resistance of core‐separated assembled BRB confined by two concrete‐infilled tubes
Author(s) -
Zhu Boli,
Guo YanLin
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.357
Subject(s) - structural engineering , core (optical fiber) , stiffness , deflection (physics) , buckling , flexural strength , materials science , ultimate load , finite element method , composite material , engineering , physics , optics
This paper presents a novel type of the core‐separated assembled BRB (CSA‐BRB). It consists of two single BRBs confined by concrete‐infilled tubes that are connected longitudinally by two continuous webs. This directly results in a sectional cavity of the CSA‐BRB by spacing two independent BRBs, and significantly enhances its cross‐sectional flexural stiffness and load‐carrying capacity. The two independent steel cores of the CSA‐BRB are strengthened and connected at its end with a core stiffener to form a robust H‐shaped sectional core, as a whole. The core stiffener is inserted into the restraining member by a distance, further remarkably improving the core strength and stiffness at un‐restrained core projections of the CSA‐BRB. The CSA‐BRB is simulated approximately by “an equivalent framed model” and accordingly its elastic buckling load was obtained by using an equilibrium method. A number of numerical examples of CSA‐BRBs were designed and investigated by using a large deflection elastic‐plastic beam element model to predict the influence of the restraining ratios on their load‐carrying capacities. An overall geometric imperfection with the amplitude of l/1000 at mid‐span of the CSA‐BRB is also involved in the analysis. The results obtained reveal that the CSA‐BRBs could achieve required load‐carrying capacity without overall failure, considering the strain hardening (for example 0.02 E ) of the core after its initial yielding, as well as the ultimate axial compressive strain of 2% applied to the core if the restraining ratio of CSA‐BRBs is greater than around 3.0.