2018 Volume 72 Issue 1 Pages 431-437
In this study based on a provision for double reinforcement ratio, γ in the AIJ standard for structural calculation of reinforced concrete structures, experimental and analytical investigations were conducted regarding ultimate behaviors in flexure of RC beams with ultra-lightweight concrete and the influence of double reinforcement ratios on the ultimate strength and toughness in flexure. As a result, compared with γ＝0（single reinforced beam）and γ＝2/3（double reinforced beam）, in case of the latter it was confirmed experimentally that the ultimate deformation capacity at crushing of concrete degrades remarkably, and analytically that the ultimate strength in flexure of the RC beam may be provided when the compressive fiber strain of the beam almost reaches the strain at compressive strength of the concrete.
