Computer aided design system on self-adjustable arrangement of reinforcing bars with smart fictitious material modeling

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The results of this research can be summarized as follows.(1) A special constitutive model of steel (smart fictitious material model) was adopted in the FEM code COM3 performing non-linear dynamic analysis of reinforced concrete structure. The proposed system was used to predict mechanical behaviors of reinforced concrete under two-dimensional and three-dimensional stress fields. Especially, a structure with an opening in the span, which may bring complex stress condition, was chosen as an example of its application. Through the study, it was shown that appropriate arrangement of reinforcement in such conditions can be automatically given, and that the specified arrangement can provide desire loading capacity. In additon, the system was applied to a design was successfully reduced down to 1/2 〜1/3 of that determined by ordinary design method.(2) In order to enhance the proposed design system, the zoning method was generalized. In the previous zoning method, the RC zone was overestimated at the point of steel yielding, while in this study the model was extended to describe both significant localization of cracking and spatial averaged state at steel yielding as a form of strain-softening-transient hardening. By this extension, the shear capacity and stiffness of member can be predicted with higher accuracy.(3) In the smart fictitious material model, local stress of reinforcement between cracks, dowel action, local deformation and bond deterioration are simplified by applying spatial-averaged approach. In this study, in order to treat these aspects in a generalized way, an enhanced stress transfer model based on microscopic nonlinearity and contact density function was proposed. It was shown in this study that the proposed model can quantify the effect of non-orthgonality of crack and reinforcement on the averaged deformation in finite element, and it allows the proposed design system to have higher accuracy.