Composite element model for the bonded anchorage head of stranded wire cable in tension

An elasto-viscoplastic model is formulated using composite element technique for the bonded anchorage head of stranded wire cable in rock mass. This composite element contains sub-elements corresponding to the rock material, the grout material, the stranded wire material, the rock/grout interface, and the grout/stranded wire interface, respectively. The displacement in each aforementioned sub-element is interpolated from the corresponding nodal displacements of the composite element. In this manner, the mesh generation taking into account of tension cable anchors may be highly facilitated. By the application of the virtual work principle, the governing equation for solving the nodal displacements of the composite element is established. The proposed model has been incorporated into the conventional finite element algorithm and implemented in the program CORE3, in which the anchorage head is embedded within the composite elements. The comparative study concerning the pull-out test has been carried out for the validation of the proposed model and algorithm.