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Frequently Asked Questions (FAQ)
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AnswerThe option controls whether to determine the minimum shear reinforcement based on the dimensions of the structural component for a slab (b/h < 5) or for a beam (b/h > 4). The height or the thickness of the surface corresponds to h, and the smallest edge length of the structural component corresponds to b (see Figure 02).
AnswerThe collapse or shear reinforcement according to DIN EN 1992‑1‑1, 9.4.1 (3) is not displayed separately as a result in RF‑PUNCH Pro and must be taken into account additionally by a designer.
AnswerThe minimum shear reinforcement A sw, min is determined in RF-PUNCH Pro by means of Equation 9.11DE from DIN EN 1992-1-1, 9.4.3.The input values used for determining A sw, min are shown in result table "2.2 Required Punching Shear Reinforcement" in the section "Minimum NB" so that the calculated value can be retraced.Please note that the calculated value A sw, min according to the standard refers to the "cross-section of a stirrup arm (or equivalent)". In RF-PUNCH Pro, this value is then multiplied by the tangential number of the individual stirrup rows, which means that the absolute value of the minimum reinforcement [cm²] in the individual perimeters can increase outwards with increasing round perimeter length or increasing number of stirrup legs.
In the module, there are the options for reinforcement, which has to be taken into account for the shear resistance analysis. The shear force resistance VRd,c is affected by the applied longitudinal reinforcement. By using the options, you can specify which longitudinal reinforcement should be used to perform the check of shear resistance. The check of shear resistance can be performed by applying the following reinforcement:
- Calculated required reinforcement
- Maximum value from required or provided reinforcement
- Automatic increment of the longitudinal reinforcement so that the shear reinforcement is avoided
For example, if you select the second option and avoid the shear reinforcement with the basic reinforcement, then the basic reinforcement is selected and resulted as the required reinforcement.
Please check the design internal forces of the affected elements.
If the cross-section of an element is completely cracked, it is not possible to carry out a shear resistance analysis on this element in the RF‑CONCRETE Surface add‑on module. Result windows of the module will also display a message No. 13 saying that the cross-section is completely cracked at these locations and the shear capacity is not designable.
Further information about the determination of shear capacity can be found in the manual of RF‑CONCRETE Surfaces in Section 126.96.36.199 Shear force resistance without shear reinforcement, which you can download from our homepage.
Check if the design software Punching Shear Reinforcement HDB from HALFEN has been successfully installed and also registered. The best way to test it is to start the design software HDB without using RF-PUNCH Pro, either from the Windows start menu or from the desktop shortcut.
If starting the program has been successful, you can use the interface of RF-PUNCH Pro to HDB for further processing.
In RF-CONCRETE Surfaces, it is always first checked whether the required reinforcement is sufficient to absorb the shear loading.
When calculating with the first option 'Use Required Longitudinal Reinforcement', you can see that the required reinforcement is sufficient for a large part of the area to ensure the shear capacity. For this reason, the required reinforcement is used instead of the basic reinforcement when determining VRd,c.
Here is a brief explanation of the options in RF-CONCRETE Surfaces 1.3 Longitudinal Reinforcement:
The program checks whether the statically required longitudinal reinforcement is sufficient to avoid the shear reinforcement. If not, the shear reinforcement is required.
If the statically required reinforcement is not sufficient, the higher value of the basic reinforcement and the statically required reinforcement are applied. If it is sufficient, the value is defined as statically required longitudinal reinforcement (because it is necessary to avoid shear reinforcement).
In cases where neither the statically required longitudinal reinforcement nor the basic reinforcement is sufficient to cover the shear reinforcement, only the required longitudinal reinforcement is applied for the calculation of VRd,c, and the additionally required shear reinforcement is calculated.
Asl is increased for the calculation of VRd,c until either the longitudinal reinforcement is sufficient, or the maximum reinforcement ratio is reached.
The results display is designed to output only the statically required reinforcements. For this reason, only the statically required reinforcement is applied for VRd,c. It is necessary to use the maximum value of the statically required and the basic reinforcement to avoid the shear reinforcement.
In cases requiring a shear reinforcement by calculation, the amount of the provided longitudinal reinforcement in the formulas has no influence. Therefore, it would not be useful to additionally consider the basic reinforcement in VRd,c.
The procedure details of the program can be well understood in the design details.
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Wind Simulation & Wind Load Generation
With the stand-alone program RWIND Simulation, wind flows around simple or complex structures can be simulated 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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