Download ATENA Program Documentation Part 2

3.7.3.6 External Cables Loading
Loading applied to external cables can be only pre-stressing. It is accessed from data tree item
Loading | External cable. Input by mouse is started by the data tree item Loading |
External cable | Add. This opens an input window for pre-stressing force. Example is shown
in Fig. 3-87.
Fig. 3-87 Loading of external cable. Pre-stressing force is entered in prototype window.
Pre-stressing force is indicated in the starting joint of the reinforcement (Joint no. 1 in the list
of joints in external cable topology, see Topology | External cable | Edit). In case of
external cables the position of active anchor has effect on distribution of stress in
reinforcement, because pre-stressing is introduced by force acting in the active anchor and can
be reduced by friction effect in deviators. This pre-stressing method can be considered as a
post-tensioning.
3.7.4 FE Mesh
FE mesh tool serves to define parameters for generation of finite element mesh. Based on
these parameters automatic mesh generator generates meshes and data of finite element
model. In case of reinforced concrete, when model includes also bar elements, the mesh
generation is performed in two phases. First, a mesh of solid 3D elements is produced within
the pre-processor. In the pre-processor the bars are still maintained as geometrical objects
without mesh. When the control is passed to analysis (Program module Run) the bar finite
elements are generated as embedded elements within existing mesh of 3D solid elements.
Thus, user cannot effect the meshing of bars, since it is governed by mesh of solid elements.
Therefore, the description in this section concerns the meshing of 3D solid elements only.
Following rules holds for mesh generation of 3D solid elements:
1. Element types: tetrahedron, brick, pyramid.
2. Brick meshes are possible only for prismatic macroelements. Any irregularity, such as
opening, line or joint on surface, refinement, can prevent brick meshing. Tetrahedron and
mixed meshes are more flexible and possible for most geometries.
60