Add-on Module for RFEM 5
RF-CONCRETE Deflect

• Deformation analyses of reinforced concrete surfaces without or with cracks (state II) by applying the approximation method (for example, deformation analysis according to 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; for example, deformation or sag of a flat slab
• Numerical results clearly arranged in tables and graphical display of the results in the model
• Complete integration of results in the RFEM printout report

The deformation analysis according to the approximation method defined in standards (for example, deformation analysis according to EN 1992‑1‑1, 7.4.3) applies to the calculation of "effective stiffnesses" in the finite elements in accordance with the existing limit state of the concrete with or without cracks. These stiffnesses are used to determine the surface deformation by repeated FEM calculation.

The effective stiffness calculation of finite elements takes into account a reinforced concrete cross-section. Based on the internal forces determined for the serviceability limit state in RFEM, the program classifies the reinforced concrete cross-section as 'cracked' or 'uncracked'. If the tension stiffening at a section should be considered as well, a distribution coefficient (according to EN 1992-1-1, Eq. 7.19, for example) is used. The material behavior for the concrete is assumed to be linear-elastic in the compression and tension zone until the concrete tensile strength is reached. This is reached exactly in the serviceability limit state.

When determining the effective stiffnesses, creep and shrinkage are taken into account at the "cross-section level". The influence of shrinkage and creep in statically indeterminate systems is not taken into account in this approximation method (for example, tensile forces from shrinkage strain in systems restrained on all sides are not determined and must be considered separately). In summary, RF-CONCRETE Deflect calculates deformations 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