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Frequently Asked Questions (FAQ)
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Yes, it is possible.For this, you can select the "Use required reinforcement for design of serviceability" check box in Window "1.4 Reinforcement," tab "Longitudinal Reinforcement."Thus, the add-on module creates the entire reinforcement required for the ultimate limit state design and/or serviceability limit state design in the reinforcement layout.In this case, the result of "Additional Reinforcement" is omitted after the calculation in the result windows in the add-on module as well as in the printout report.It is possible to combine the "Use required reinforcement for design of serviceability" option with the "Increase the required longitudinal reinforcement automatically for serviceability liimit state design" option.
When using the automatic arrangement of the reinforcement, make sure that the additional reinforcement is applied, if necessary, for the serviceability limit state designs in addition to the basic reinforcement. The default setting in the add-on module is selected in such a way that the required reinforcement from the ultimate limit state is also applied for the SLS.
You can select the reinforcement that is applied for the SLS in "Additional Reinforcement for Serviceability State Design." The Info button explains the individual options (Figure 02).
The reinforcement applied to the designs can be followed by using the "Selected Reinforcement for SLS Check" function (Figure 03).
You can find the provided basic reinforcement for reinforced concrete surfaces by specifying a rebar spacing and rebar diameter in Window 1.4 of RF‑CONCRETE Surfaces under the "Longitudinal Reinforcement" tab.If you enter a diameter and a distance, the program automatically determines the reinforcement content [cm²/m].Click the "OK" button to import this value.
You have probably entered the wall as a 2D model.Figure 01 - Dialog Box with Model General Data and Setting of Model TypeIf you enter the wall as a 2D model, you can only enter symmetric reinforcement on inside and outside in RF‑CONCRETE Surfaces.In Window 1.4 of RF‑CONCRETE Surfaces, you can only find one reinforcement layout, where "top" and "bottom" are summarized.Now, if you specify the reinforcement of 7.54 cm²/m in the 2D model, you get the provided basic reinforcement of 3.77 cm²/m in the result window 2.1 because RF‑CONCRETE Surfaces applies a half inside and outside.If you now want to consider the reinforcement of 7.54 cm²/m for each wall side, it is necessary to enter the reinforcement of 15.08 cm²/m accordingly for the 2D model.This would result in the desired reinforcement of 7.54 cm²/m for each side.If you enter a 3D model instead of the 2D model (setting in General Data of the model, see Figure 01), you can enter the settings for the top and bottom part of the surface separately in RF‑CONCRETE Surfaces.
AnswerNo, the basic reinforcement defined in RF‑CONCRETE Surfaces is not consideredwhen determining internal forces in RFEM. In RFEM, the internal forces are determined by using the modulus of elasticity of the selected concrete. The amount of reinforcement has no influence in this case (linear-elastic calculation, state I).The behavior is different when performing nonlinear design in state II (cracked state) in the serviceability limit state by using the RF‑CONCRETE NL add‑on module. In this case, you enter the provided basic reinforcement, which is to be considered for the nonlinear calculation in state II. The internal forces will be determined with the effective stiffnesses (state II) when performing the nonlinear design (available for SLS only). Thus, the defined reinforcement has an influence on the internal forces.You can evaluate these internal forces (from the state II influenced by the defined reinforcement) in the results of RF‑CONCRETE Surfaces. For this, see Figure 01 with the Results navigator of the RF‑CONCRETE Surfaces add‑on module.
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.
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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