3.4.2 Uspořádání výztuže

Uspořádání výztuže

This tab manages the geometric specifications for the reinforcement.

The reinforcement mesh can be defined with two or three reinforcement directions for each surface side.

For serviceability limit state designs, only a reinforcement mesh with two directions is allowed.

The definition of the "top" and "bottom" surface side is described below in the Concrete Cover for Reinforcement section.

You can refer the concrete covers that you can specify in the Concrete Cover for Reinforcement section to the reinforcement's Centroid or Edge distance.

When you select the Edge option in a pure ultimate limit state design, you have to specify the Bar diameter D.

You need to specify the concrete covers of the Basic Reinforcement and, if necessary, the Additional Reinforcement for both sides of the surface. The dimensions represent either the centroids d of the individual layers or the reinforcements' edge distances c_nom in the direction φ₁. The reinforcement directions must be defined in the dialog section below.

The "top" and the "bottom" surface side is defined as follows: The bottom surface is defined in the direction of the positive local surface axis z, the top surface accordingly in the direction of the negative local z-axis.

The RFEM graphic shows the xyz coordinate systems of the surfaces once you move the pointer across a surface. You can also use the shortcut menu of a surface (by right-clicking it) to display or hide the axes.

To display the surface sides in different colors, select Colors in Graphics According to → +/- z Surface Side in the Display navigator (see figure on the left).

You can change the orientation of the local z-axis of a surface by using the Reverse Local Axis System option in the shortcut menu (see Figure 3.28). This way you can, for example, unify the orientation of walls in order to unambiguously assign the top and bottom reinforcement sides for vertical surfaces.

The model types "wall" -- 2D - XZ (u_X/u_Z/φ_Y) or "diaphragm" -- 2D - XY (u_X/u_Y/φ_Z) are models that are exclusively subjected to compression or tension in the component plane. In such a case, it is not possible to create different reinforcement meshes for each surface side so that the input possibilities are limited to uniform concrete covers on both sides.

If you select the According to Standard check box, the [Edit] button becomes available. Use this button to open the dialog box shown in Figure 3.29.

In the upper section, you can define the parameters (exposure class, abrasion class, etc.) according to the standard. Based on these parameters, RF-CONCRETE Surfaces determines the required concrete covers.

You can specify the parameters separately for each surface side in the two dialog tabs.

The reinforcement directions φ are related to the local x-axes of the finite elements. In the Edit Surface dialog box of RFEM, you can check and, if necessary, adjust the axis system of the surfaces for the results output.

For curved surfaces, it is recommended to check the axes of the finite elements graphically: In the Display navigator of RFEM, select FE Mesh → On Surfaces → FE Axis Systems x, y, z, → Indexes.

The reinforcement directions have to be specified for each layer by means of the angles φ. Only positive angles are allowed. They respectively represent the clockwise rotation of the reinforcement direction in relation to the corresponding x-axis.

For the model types "wall" -- 2D - XZ (u_X/u_Z/φ_Y) or "diaphragm" -- 2D - XY (u_X/u_Y/φ_Z), it is not possible to create different reinforcement meshes for each side of the surface. Thus, the input options are limited to uniform reinforcement directions on both surface sides.