Concrete pressure

About the program

Reference: NS-EN 1992-1-1:2004+A1+NA – 3.1.6(1)P and 3.1.2(6)

Calculates the design compressive capacity NRd for concrete cross-sections according to NS-EN 1992-1-1. Checks whether the axial load at ultimate limit state is within capacity.

Also supports calculation of reduced compressive strength at a given concrete age in days.

Typical use: Checking concrete columns and compression-loaded cross-sections.

Illustration of rectangular concrete section

Key formulas

Design compressive strength

fcd=fck⋅αccγcf_{cd} = \frac{f_{ck} \cdot \alpha_{cc}}{\gamma_c}
fckf_{ck}Characteristic cylinder strength (MPa)
αcc\alpha_{cc}Long-term factor (= 0.85)
γc\gamma_cPartial factor for concrete (= 1.5)

Compressive capacity

NRd=A⋅fcdfckγcN_{Rd} = A \cdot f_{cd}\vphantom{\dfrac{f_{ck}}{\gamma_c}}
AACross-sectional area (mm²)
fcdf_{cd}Design compressive strength (MPa)
NRdN_{Rd}Design compressive capacity (kN)

Inputs

  • Concrete grade (B25–B90) or custom fck
  • Cross-section: rectangular, circular or custom area
  • Design axial force, Nf
  • Concrete age, t (optional – for reduced curing time)

Outputs

  • Design compressive strength, fcd
  • Design capacity, NRd
  • Utilization, Nf / NRd
  • Reduced fcd(t) at given age (if enabled)

Assumptions

  • Axial force only – no bending moment or eccentricity
  • No buckling check (slenderness not included)
  • Plain concrete cross-section, no reinforcement

Video coming soon.