Research Article

Single Spring Joint Element Based on the Mixed Coordinate System

Figure 1

(a) Discrete model of nonlinear FEM for bond-slip problems (e.g., a joint element with zero thickness is inserted to the interface between two materials, which has elastic stiffness but no physical dimensions; i.e., it is not a real component but a mechanical model). (b) Bond zone element (hypothetical bond-slip layer with thickness , composed of a series of parallel corpus vertebrae outside the steel bar to simulate softened layer after internal cracks in concrete, reflecting wedge action of deformed bars).