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Frequently Asked Questions (FAQ)
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AnswerA collapse or tear-resistance according to DIN EN 1992-1-1, 9.4.1 (3) is not output separately in RF-PUNCH Pro and must be additionally taken into account by the designer.
AnswerBy default, the compute core of the cross-section program SHAPE-THIN is used in the RF- / ALUMINUM add-on module to determine the stresses of the effective cross-section in an iterative procedure. This method is precise because all vertices and edges of the cross-section are considered, but can be very time-consuming for complex sections.Alternatively, it is possible to determine the effective cross-section by means of a simplified analytical method (see Figure 01) that runs much faster. In this approach, corners, fillets, etc. are neglected and subsequently compensated by a factor. No iterative calculation is performed. Therefore, the effective cross-section values may be higher than with the SHAPE-THIN calculation.In such a case, it is recommended to carry out the calculation with the analytical method and then to design only the governing structural component with the governing load combination with the SHAPE-THIN solution.
In RF-PUNCH Pro, RFEM displays all surfaces connected to the selected nodes for input in the "1.4 Longitudinal Reinforcement" dialog box. For example, in a punching shear design on a wall corner, the surfaces that actually represent the walls are also defined. I can also define a longitudinal reinforcement for these surfaces. Is this somehow applied? Why do I see these surfaces in the dialog 1.4?
AnswerYou are right. In the input dialog box "1.4 Longitudinal Reinforcement", we first display all surfaces connected to the selected node for design. That means also the walls at the wall corner you mentioned.However, the definition of the position of the longitudinal reinforcement for these walls does not become relevant for the punching shear design in the floor slab.Starting with version 5.19.01 of RFEM, a filter has been installed with which only the surfaces for which the definition of the position of the longitudinal reinforcement is relevant can be displayed.You can find the Filter button in input dialog box 1.4 on the bottom right. See Figure 01.
I have a foundation, which is held by subsequent frost aprons (Zerrbalken) in one direction (X or Y direction). From the internal force determination in RFEM I get horizontal bearing forces in the X- and X-direction. This is correct so far. Due to the frost aprons, the foundations are stored in the X-direction but. Can I "switch off" or ignore a bearing response from RFEM for the design of the foundation in RF- / FUND Pro?
AnswerYes, this is possible.You will find the controller in the design details of the respective design case in RF- / FUND Pro.On the one hand, you can select the bearing load (Px, Py, Pz, Mx or My) that should not be taken into account in the design. On the other hand, you can also determine whether the forces or moments should only be deactivated for a specific direction or for all directions.It is important, however, that disabling the bearing load works for all proofs of the design case. If the bearing load Px is to be deactivated only for the proof of sliding, but not for all other checks, then you can control this with two design cases.
AnswerThe static height d for the proof "bending resistance safety equivalent beam" is given by the plate thickness minus the set concrete cover on the underside of the block foundation, the diameter of the regular bending reinforcement of the plate on the underside in both directions and half the diameter of the reinforcement of the "replacement beam".The static height d is taken into account differently in both directions (bending around the x and the y axis). This must be taken into account when evaluating the calculation in the result table 2.2 "Essential proofs - resistance to bending damage - replacement beams".
Ultimate Limit StateSLS:
Serviceability Limit State
EQU:Proof of position security; Loss of position security of the structure or one of its parts z. B. by tilting, floating or liftingSTR:
Failure of the structure or individual parts by exceeding the material strength, excessive deformation, reaching a kinematic state or an unstable positionGEO:too much deformation or failure of the subsoil
AnswerIn order to carry out a fire protection certificate in STEEL EC3, you must select a load case or a load combination in the "Fire protection" tab for which the fire protection certificate is to be carried out.As soon as you have selected a load for the fire protection certificate, an additional mask "Fire protection bars" or "Fire protection - Rod sets" appears in the module navigator on the left (if rod sets are to be dimensioned in the module case). In this screen 1.10 or 1.11 further settings for the fire protection proof of the component can be set.Further detail settings (eg. example required duration of fire protection, etc.) can also be found by pressing the [Details ...] button and selecting the "Fire protection" tab.Further information can be found in the manual for STAHL EC3.
AnswerFor the design of steel surfaces please use the module of the same name RF-STEEL Surfaces. If you also want to consider local denting, then the additional modules RF-STABIL (to determine the bulge and branching loads) and RF-IMP (to determine the imperfection figure, based on the bulge pattern) are also recommended.
AnswerUnfortunately not. Intermediate supports and nodal supports have to be set manually. The default configuration for effective lengths is 1,0*member length and for set of members, one nodal support with definition u_y' and phi_x' is defined on each side of the set of member.To speed up the process of defining nodal supports, you can pick more nodes in one step by using the highlighted function in the attached picture.
AnswerThe modulus of elasticity of the material is reduced for the proofs according to EC 3, but not for the internal forces, since this is not intended according to the method of DIN EN 1993-1-2. It is always assumed that the structure is cold. In the calculation of the internal forces, one has to take into account only the internal constraint of temperature stress, if this is present.
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