Precast concrete structure increases because of its advantages such as enhancement of the productivity. Analysis by using finite element method has a possibility to make evaluation and design of precast concrete structure more reasonable. A reliable dynamic model of joint interface between precast concrete and site concrete is required for the analysis. This paper focuses the joint interface connected by deformed reinforcing bars. Experiment of element specimens representing the interface are conducted and numerical model for a relationship between shear force and shear displacement of the interface is proposed. Deformation of the reinforcing bar is regarded as combination of two arcs and established bond - slip models of the reinforcing bar are applied in the model. A simpler model for application to FE analysis, that is a bilinear slip - strain relationship based on the experimental curve, is also proposed.

 This study presents a kinematic model for shear-critical RC columns subjected to freeze-thaw action based on upper bound theorem. The developed model enables derivation of the shear resistance of damaged concrete when the displacement field is divided into undamaged and damaged zones based on freeze-thaw depth obtained from on-site inspections. The accuracy of the model is verified by comparing its predictions with an earlier published database on RC columns failing in shear after freeze-thaw exposure. The predicted shear strengths show good agreement with the test results within error of 20%. Thereafter, the current shear strength of an existing RC bridge pier with severe frost damage is analyzed by the model. Results demonstrate that the freeze-thaw depth may allow rational structural assessment.