Answer:
You can enable the export of nonlinear stiffness to cracked structures in Settings for Nonlinear Calculation in the RF‑CONCRETE Members or RF‑CONCRETE Surfaces add-on modules. In the Edit Load Cases and Combinations dialog box, check the additional options for the selected combinations. A new tab appears, where you can activate the stiffness transfer from the add-on modules.
Question
When selecting the nonlinear method of check in the serviceability limit state design, there is the option to export the stiffness of the already cracked structure. Is it possible to recalculate the internal forces with these stiffnesses?
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Describing the procedure for the serviceability limit state design of a floor slab made of steel fiber reinforced concrete. This article shows how to perform the corresponding design for the SLS by means of the iteratively determined FEA results.
Steel-fiber-reinforced concrete is mainly used nowadays for industrial floors or hall floors, foundation plates with low loads, basement walls, and basement floors. Since the publication in 2010 of the first guideline about steel-fiber-reinforced concrete by the German Committee for Reinforced Concrete (DAfStb), a structural engineer can use standards for the design of the steel fiber-reinforced concrete composite material, which makes the use of fiber-reinforced concrete increasingly popular in construction. This article describes the nonlinear calculation of a foundation plate made of steel fiber-reinforced concrete in the ultimate limit state with the FEA software RFEM.
When modeling a reinforced concrete rib with a masonry wall above, there is the risk that the rib is underdesigned if the structural behavior of the masonry is not correctly considered and the connection between the masonry wall and downstand beam is not modeled sufficiently accurately. This article deals with this issue and shows the possible modeling options of such a structure. In this example, the reinforcement is determined only from the internal forces and without secondary minimum reinforcement.
Steel-fiber-reinforced concrete is mainly used nowadays for industrial floors or hall floors, foundation plates with low loads, basement walls, and basement floors. Since the publication in 2010 of the first guideline about steel-fiber-reinforced concrete by the German Committee for Reinforced Concrete (DAfStb), a structural engineer can use standards for the design of the steel fiber-reinforced concrete composite material, which makes the use of fiber-reinforced concrete increasingly popular in construction. This article explains the individual material parameters of steel-fiber-reinforced concrete and how to deal with these material parameters in the FEM program RFEM.
Do you have individual column sections and angled wall geometries, and need punching shear design for them?
No problem. In RFEM 6, you can perform punching shear design not only for rectangular and circular sections, but for any cross-section shape.
The Concrete Design add-on provides you with the option to perform the simplified fire resistance design according to EN 1992‑1‑2 for columns (Section 5.3.2) and beams (Section 5.6).
The following design checks are available for the simplified fire resistance design:
- Columns: Minimum cross-sectional dimensions for rectangular and circular sections according to Table 5.2a as well as Equation 5.7 for calculating time of fire exposure
- Beams: Minimum dimensions and center distances according to Table 5.5 and Table 5.6
You can determine the internal forces for the fire resistance design according to two methods.
- 1 Here, the internal forces of the accidental design situation are included directly into the design.
- 2 The internal forces of the design at normal temperature are reduced by the factor Eta,fi (ηfi), then used in the fire resistance design.
Furthermore, it is possible to modify the axis distance according to Eq. 5.5.
With the Concrete Design add-on, you can perform the fatigue design of members and surfaces according to EN 1992‑1‑1, Chapter 6.8.
For the fatigue design, you can optionally select two methods or design levels in the design configurations:
- Design Level 1: Simplified design according to 6.8.6 and 6.8.7(2): The simplified design is performed for frequent action combinations according to EN 1992‑1‑1, Chapter 6.8.6 (2), and EN 1990, Eq. (6.15b) with the traffic loads relevant in the serviceability state. A maximum stress range according to 6.8.6 is designed for the reinforcing steel. The concrete compressive stress is determined by means of the upper and lower allowable stress according to 6.8.7(2).
- Design Level 2: Design of damage equivalent stress acc. to 6.8.5 and 6.8.7(1) (simplified fatigue design): The design using damage equivalent stress ranges is performed for the fatigue combination according to EN 1992‑1‑1, Chapter 6.8.3, Eq. (6.69) with the specifically defined cyclic action Qfat.
The Concrete Design add-on allows you to perform the seismic design of reinforced concrete members according to EC 8. This includes, among other things, the following functionalities:
- Seismic design configurations
- Differentiation of the ductility classes DCL, DCM, DCH
- Option to transfer the behavior factor from a dynamic analysis
- Check of the limit value for the behavior factor
- Capacity design checks of "Strong column - weak beam"
- Detailing and particular rules for curvature ductility factor
- Detailing and particular rules for local ductility
Are the models and presentations from Info Day 2018 freely available, and can you send them to me?
When converting from the manual definition of reinforcement areas to the automatic arrangement of reinforcement according to Window 1.4, the result of the deformation calculation differs, although the basic reinforcement has not been modified. What is the reason for this change?
I obtain different results when comparing the deformation analysis in the RF‑CONCRETE add-on modules and another calculation program. What could be the reason for this?
Is it also possible to design flat slabs in RF‑TENDON and RF‑TENDON Design?
In connection with the nonlinear calculation for the serviceability limit state design checks, I obtain implausibly large values for crack width and deformation in the RF‑CONCRETE modules (see Image 01). What is the cause, and how can I fix the problem?
Is it also possible to perform a deformation analysis in the cracked state for a 2D model in RF‑CONCRETE Surfaces?
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