Concrete Design | Deformation Analyses | Features

  • Deformation analyses of reinforced concrete surfaces without or with cracks (state II) by applying the approximation method (for example, deformation analysis according to ACI 318-19, 24.3.2.5 or EN 1992‑1‑1, Cl. 7.4.3 )
  • Tension stiffening of concrete applied between cracks
  • Optional consideration of creep and shrinkage
  • Graphical representation of results integrated in RFEM, such as deformation or sag of a flat slab
  • Clear numerical result display in the detail dialog box
  • Complete integration of results in the RFEM printout report

Concrete Design | Deformation Analysis | Input

Are you looking for a deformation calculation? Check the Serviceability Configuration, where it can be activated. You can also control the consideration of long-term effects (creep and shrinkage) and tension stiffening between cracks in the dialog box above. The creep coefficient and shrinkage strain are calculated using the specified input parameters, or you can define them individually.

Furthermore, you can specify the deformation limit value individually for each structural component. The max. deformation is defined as the allowable limit value. In addition, you have to specify whether you want to use the undeformed or the deformed system for the design check.

Concrete Design | Punching | Design

You have two options in RFEM. On the one hand, you can determine the punching load from a single load (from column/loading/nodal support) and the smoothed or unsmoothed shear force distribution along the control perimeter. On the other hand, you can specify them as user-defined.

Calculate the design ratio of the punching shear resistance without punching reinforcement as a design criterion and the program will deliver you the corresponding result. In the case of exceeding the punching shear resistance without punching reinforcement, the program determines the required punching reinforcement as well as the required longitudinal reinforcement for you.

Concrete Design | Deformation Analysis | Design

The standards already specify the approximation methods (for example, deformation calculation according to EN 1992‑1‑1, 7.4.3, or ACI 318‑19, 24.3.2.5) that you need for your deformation calculation. In this case, the so-called effective stiffnesses are calculated in the finite elements in accordance with the existing limit state with / without cracks. You can then use these effective stiffnesses to determine the deformations by means of another FEM calculation.

Consider a reinforced concrete cross-section for the calculation of the effective stiffnesses of the finite elements. Based on the internal forces determined for the serviceability limit state in RFEM, you can classify the reinforced concrete cross-section as "cracked" or "uncracked". Do you consider the effect of the concrete between the cracks? In this case, this is done by means of a distribution coefficient (for example, according to EN 1992‑1‑1, Eq. 7.19, or ACI 318‑19, 24.3.2.5). You can assume the material behavior for the concrete to be linear-elastic in the compression and tension zone until reaching the concrete tensile strength. This procedure is sufficiently precise for the serviceability limit state.

When determining the effective stiffnesses, you can take into accout the creep and shrinkage at the "cross-section level." You don't need to consider the influence of shrinkage and creep in statically indeterminate systems in this approximation method (for example, tensile forces from shrinkage strain in systems restrained on all sides are not determined and have to be considered separately). In summary, the deformation calculation is carried out in two steps:

  1. Calculation of effective stiffnesses of the reinforced concrete cross-section assuming linear-elastic conditions
  2. Calculation of the deformation using the effective stiffnesses with FEM

Concrete Design | Deformation Analyses | Results

Have you carried out the design successfully? The results of the deformation analysis are now listed in clearly arranged output tables or detailed dialog boxes with info text. The program shows you all intermediate values in a comprehensible manner. Graphical representation of design ratios and deformation in RFEM allows you for a quick overview of critical areas.

Due to the results output of the design checks with all intermediate results, you can follow the calculation to the smallest detail. The complete integration of results in the RFEM printout report ensures that you obtain verifiable structural design.