A time-dependent structural analysis method under multi actions in consideration of drying shrinkage due to moisture transfer and rebar corrosion due to chloride ions penetration as well as external load actions was developed. The Rigid-Body-Spring Networks (RBSN) model and the truss networks model were used for structural analysis and mass transfer analysis, respectively. In addition, mass transfer through bulk concrete and mass transfer through cracks by setting truss networks on the boundaries of Voronoi particles, was also considered. The developed method was confirmed to simulate well the deterioration process due to mass transfer for initial cracking behavior and ultimate behavior of concrete structures.

This research was carried out in order to evaluate the bond characteristic between concrete and deformed bar in Macro level by meso-scale analysis using Rigid Body-Spring Model (RBSM). In the analysis, lugs of deformed bar were modeled considering the geometry. By the meso-scale analysis using the stress-strain relationship obtained from the tests in macro-scale, it was possible to understand the development of the internal cracks around the lugs as well as the development of the cracks and the bond behavior in macro-scale. Moreover, it was investigated the effect on the bond behavior of the lug spacing and the stiffness of the bar. As the results, the lug spacing was influence factor and the stiffness of the bar did not influence to the bond behavior.

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In recent years, interest in early age concrete cracking has increased due to its effects on the durability and performance of concrete structures. A time-dependent material model and a structural analysis method have been developed to evaluate thermal cracking behavior. To simulate such behavior at early ages, a solidified constitutive model is proposed, which is based on the solidification concept with dependence on time and strain histories. The unified numerical model consists of a Rigid-Body-Spring Network, representing the structural behavior, combined with a truss model to represent heat transfer. Wall concrete structures are analyzed to verify the solidified constitutive model and the overall approach. The proposed model results and the experimental results show reasonable agreement in terms of cracking behavior, stress distributions and structural deformations.

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