Abstract
A purpose of this study is to propose multi-axial restoring force model of slipping type of R/C members. Firstly, three-directional loading tests were carried out in order to understand tri-axial nonlinear restoring force characteristics of R/C members without bond of longitudinal bars, which the members without bond showed slipping behaviors in its one-directional force-deformation relationships. Then, based on consideration of the test results, bi-axial restoring force characteristics of slipping type was formulated. A matrix was used to express slipping area in this model. Finally, numerical results with the proposed model were compared with the test results to verify the model.
