Nonlinear System Analysis

Remaining concrete tensile stress (tension stiffening) after the initial crack formation
Remaining concrete tensile stress (tension stiffening) after the initial crack formation
Directional representation of the associated crack strains
Directional representation of the associated crack strains

Nonlinear system analysis can be used to determine the internal forces and deformation values of 2D and 3D beam and shell structures made of reinforced concrete and steel under consideration of geometric and physical nonlinearities. The program is especially well-suited for checking the ultimate limit state (buckling safety check) and the serviceability (deformations, internal forces) of the entire system.

For solid elements, the stress state is calculated according to the Raghava, Rankine, Drucker-Prager or Lubliner yield condition. In addition, the damage models according to Mazars, De Vree and an elasto-plastic damage model (Lubliner, Lee & Fenves) are available.  The Mohr-Coulomb model was implemented specifically to estimate the load-bearing behavior of soils.

Nonlinear System Analysis:

  • Reinforced and prestressed concrete with stress-strain-curve according to EN 1992, DIN,  OENORM and SIA
  • Effect of concrete on tension between cracks
  • Ultimate limit state
    • Check under consideration of existing reinforcement
  • Serviceability limit state
    • Deformations under consideration of existing reinforcement
  • Consideration of long-time deformations as result of concrete creep and shrinkage
  • Steel with bilinear stress-strain curve under consideration of the Huber-von Mises yield criterion and interaction with all internal forces
  • Bilinear stress-strain curve and individually definable compressive and tensile strength (Raghava, Rankine, Drucker-Prager or Lubliner yield criterion)
  • Damage models according Mazars and De Vree and elasto-plastic damage (Lubliner, Lee & Fenves) for solid element constructions
  • Soil model according to Mohr-Coulomb, Phi-C Reduction
  • Calculations in the supercritical range using the arc length method
  • Calculation of load-displacement curves
  • Equilibrium on the deformed system according to second-order theory and advanced geometrical nonlinear theory
  • Bedding with bilinear bedding curve for frameworks
  • Automatic reinforcement increase during ultimate limit state check for frameworks

Reinforced and Prestressed Concrete Structures

The stress-strain curves for nonlinear internal force calculation are applied based on the corresponding standard and the material selected. The corresponding material partial safety factors are also taken into consideration. The concrete tensile strength can be considered with softening or bilinear behavior. This calculation is based on the reinforcing steel from a previous design. Alternatively, you can also specify the reinforcement level directly. Existing tension members strings are also considered. The concrete creep is realized by modifying the underlying stress-strain curves.

For frameworks, the reinforcement can be automatically increased so as to arrive at the desired structural safety or to comply with the permitted strain. The biaxial concrete behavior is implemented for area elements under consideration of the strengths according to Kupfer/Hilsdorf/Rüsch and the concept of equivalent one-axis strain. In addition to the deformations and internal forces in state II, the remaining concrete and reinforcing steel stresses and its strains are output.

Steel and Bilinear Material Structures

The calculation is carried out according to the theory of plasticity. The check guarantees that, under consideration of the internal force interaction, the full-plastic internal force limits are not exceeded and that the system is in a stable state of equilibrium. In addition to the internal forces and deformations, the nonlinear stress and strain distribution in the structure is made available.