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Warning 155 appears once the spacing of the stirrup legs of a beam in the transverse direction exceeds the limit value st,max given by the standard (see Eurocode 2, Section 9.2.2 (8)). The problem can be solved by increasing the number of stirrup legs under the settings for the stirrup reinforcement.
The list of possible diameters can be extended or modified in the add-on modules CONCRETE, RF‑CONCRETE Members, or RF‑/CONCRETE Columns by using the "Edit List of Possible Diameters" button.
The design of a column with RF‑CONCRETE Columns determines a provided reinforcement, among other things. This is displayed in Table 4.1 and illustrated in the graphics below and in the table on the right.
You can use the "Edit Reinforcement" button to change the reinforcement, if necessary. Click the button to open the "Edit Longitudinal Reinforcement" dialog box (see the image). It includes the table for the "Position of Reinforcement Bars." Here you can delete rows by selecting the row that contains the member to be removed and then clicking the button below.
If "Uniformly surrounding" is set for the reinforcement distribution, the longitudinal reinforcement can be increased or decreased by selecting the number of members in four steps.
Then, it is necessary to recalculate the design for the modified reinforcement arrangement in order to update the design ratio.
The described procedure is shown in the explanatory video.
In RF-/CONCRETE Members, the depth of the concrete compression zone can be viewed in the intermediate results of Window "4.1 Serviceability Limit State", see Image 01.
The output takes place within the printout report when activated accordingly.
In RF-CONCRETE Surfaces, the depth of the concrete compression zone is only determined if the cross-section is cracked. It can be viewed in Window "3.1 Serviceability Limit State" in the design details of a point, see Image 02.
You can use the Excel button to export the design details.
The descriptions of the reinforcement in the Results navigator are defined as follows:
As,-z (top) :
- Upper longitudinal reinforcement, that is, all longitudinal reinforcement that is above the centroidal axis of the cross-section, see Image 01
As,+z (bottom) :
- Bottom longitudinal reinforcement, that is, all longitudinal reinforcement that is below the centroidal axis of the cross-section
- Total longitudinal reinforcement of the cross-section that is required due to torsion
As,-z (top) + As,T/2 :
- Upper longitudinal reinforcement (see above) plus half of the required longitudinal reinforcement from torsion
As,+z (bottom) + As,T/2 :
- Bottom longitudinal reinforcement (see above) plus half of the required longitudinal reinforcement from torsion
- Stirrup reinforcement from torsion
- Always single-leg, that means: reinforcement content from one leg on one stirrup member
- Resulting from the theoretical assumption of a spiral stirrup reinforcement
- Stirrup reinforcement from shear force
- Two-, three-, or four-leg, that means: reinforcement content from one leg on two, three, or four stirrup members
- Setting the number of legs under stirrup parameters, Window "1.6 Reinforcement", "Stirrups" tab, see Image 02
2*asw,T,stirrup + asw,V,stirrup :
- Total stirrup reinforcement from torsion and shear force
- In this case, two-leg for torsion, therefore Factor 2 before asw,T,stirrup, shear reinforcement according to the setting from Image 02
AnswerIn terms of the consideration of creep and shrinkage, the program concept is as follows: Creep and shrinkage are only considered in RF‑CONCRETE Members if there is a curvature and if the cross-section is cracked. The explanation of this can be found in the manual, see Chapter 18.104.22.168.The concept for determining the longitudinal stiffness is designed for curved components. In the case of pure axial loading, the program is not able to determine the exact deformation in connection with the creep and shrinkage according to the current concept.
The deformation uz,local under the "Serviceability Limit State Design" category only refers to the simplified analytical method. However, in the case of a nonlinear calculation, you can display the deformations in the "Nonlinear Analysis" category for the serviceability limit state by using the "Nodal Displacement ug" entry.
The method described in the theoretical background for determining a crack width corresponds to the direct crack width calculation according to DIN EN 1992‑1‑1, 7.3.4.
This method is based on the approach of mean strain according to Equation (7.9). In this theoretical approach, the crack width of primary cracks is only determined. The crack spacing (sr,max) describes the theoretical distance to the next primary crack, and at the same time, it represents the length over which the strain difference is considered and finally the crack width is calculated.
For the design of a ring beam, I usually have Mz moments, which causes the formation of the compression and tension zone on the right and left of the cross-section. However, the reinforcement in CONCRETE is arranged at the top and bottom of the cross-section. How can I set the reinforcement to be arranged on the right and left?
In RF‑CONCRETE Members, the deformation in the cracked state is determined by using a coefficient "ζ" (according to EN 1992‑1‑1, 7.4.3 with similar concepts applied to the ACI 318 and CSA A23.3 standards). For this simplified method, the coefficient ζ is only determined once per member. The linear deformation is scaled up according to the governing location in the member.
In this context, it is possible to determine different coefficients ζ for the individual members. When scaling the linear deformation, sudden drops occur between the individual members.
To avoid this effect, it is recommended to use sets of members.
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Wind Simulation & Wind Load Generation
With the stand -alone program RWIND Simulation, you can simulate wind flows around simple or complex structures by means of a digital wind tunnel.
The generated wind loads acting on these objects can be imported to RFEM or RSTAB.
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