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Frame Analysis Calculator

Geometry
Nodes
IDX (m)Y (m)SupportRemove
Members
IDStart nodeEnd nodeRemove
Member section & material (applied to all members)
Member UDLs (kN/m, downward)
Member M1
Member M2
Member M3
Node loads (kN, kN·m)
Node C0
Node C1
Node C2
Node C3

Frame Analysis

EN 1993-1-1 · HEA200 · S235
M1: 17.7 kN·mM2: 72.3 kN·mM3: 49.7 kN·mC0C1C2C3
Governing checkMember M273.4%ALL CHECKS PASS
Checks
CheckDemandCapacityUtil.Status
M1 — bending17.7 kN·m100.9 kN·m17.6%PASS
M1 — shear2.6 kN245.3 kN1.1%PASS
M1 — axial39.7 kN1265.0 kN3.1%PASS
M1 — interaction20.7%PASS
M2 — bending72.3 kN·m100.9 kN·m71.6%PASS
M2 — shear50.3 kN245.3 kN20.5%PASS
M2 — axial22.6 kN1265.0 kN1.8%PASS
M2 — interactionGOVERNS73.4%PASS
M3 — bending49.7 kN·m100.9 kN·m49.2%PASS
M3 — shear22.6 kN245.3 kN9.2%PASS
M3 — axial50.3 kN1265.0 kN4.0%PASS
M3 — interaction53.2%PASS
  • First-order elastic analysis only — no P-Δ (second-order) effects.
  • No lateral-torsional buckling check on frame members.
  • EC3 combined axial+bending uses a disclosed conservative linear interaction (N/Nb,Rd + My/Mc,Rd ≤ 1), not the full §6.3.3 sway-buckling interaction.
  • A member’s own UDL is automatically resolved into along-member and perpendicular components regardless of the member’s angle.
  • A concentrated moment at a node transfers into every member framing into that node, since joints are modeled as fully rigid.
  • Geometry and results are in SI units (m, kN, kN·m) only.
Frame Analysis v1.0Validated against 33 benchmark cases →Learn: What does "statically determinate" actually mean? →Learn: Buckling: why slender steel members fail differently than stocky ones →Learn: Moment frames vs braced frames vs shear walls: how lateral systems actually differ →
Stiffness-method solve
Beam-column assembly & solve
Kff · Uf = Pf (3 DOF/node: u, v, θ)
12 total DOF, 6 free
Solved — nodal displacements/rotations recovered
Global equilibrium check
ΣFx = ΣFy = 0 (applied + member self-loads + reactions)
ΣFx=0.000 kN, ΣFy=-0.000 kN
Satisfied
Member end forces & governing demand
Member M1 (HEA200)
Recovered via q = k·(T·u) + FEF
L=4.00 m
Mmax=17.7 kN·m, Vmax=2.6 kN, N=-39.7 kN
Member M2 (HEA200)
Recovered via q = k·(T·u) + FEF
L=6.00 m
Mmax=72.3 kN·m, Vmax=50.3 kN, N=-22.6 kN
Member M3 (HEA200)
Recovered via q = k·(T·u) + FEF
L=4.00 m
Mmax=49.7 kN·m, Vmax=22.6 kN, N=-50.3 kN
Support reactions
Reaction at C0
Rx=2.6 kN, Ry=39.7 kN, Mz=7.2 kN·m
Reaction at C3
Rx=-22.6 kN, Ry=50.3 kN, Mz=40.8 kN·m
Governing member M2
§6.2.5(2)Section modulus for Class 1
Class 1/2 → plastic modulus
Wpl,y = 429.5 × 10³ mm³
Wpl,y = 429500 mm³
§6.2.5(2)Design resistance for bending
Mc,Rd = Wpl,y · fy / γM0
Mc,Rd = 429500 × 235 / 1
Mc,Rd = 100.9 kN·m
§6.2.5(1)Cross-section bending check
MEd / Mc,Rd ≤ 1.0
72.3 / 100.9
Ratio = 0.716 → OK
§6.2.6(3)aShear area, rolled I-section
Av = A − 2b·tf + (tw + 2r)·tf ≥ η·hw·tw
Av = 5383 − 2×200×10 + (6.5 + 2×18)×10 = 1808; min 1326
Av = 1808 mm²
§6.2.6(2)Plastic shear resistance
Vpl,Rd = Av · (fy/√3) / γM0
Vpl,Rd = 1808 × (235/√3) / 1
Vpl,Rd = 245.3 kN
§6.2.6(6)Web shear buckling check
hw/tw ≤ 72ε/η, else EN 1993-1-5 §5 governs
26.2 vs 60.0
OK — no shear buckling check needed
§6.2.6(1)Shear check
VEd / Vpl,Rd ≤ 1.0
50.3 / 245.3
Ratio = 0.205 → OK
Table 5.2Material coefficient
ε = √(235 / fy)
ε = √(235 / 235)
ε = 1.000
Table 5.2Flange (outstand in compression)
c = (b − tw − 2r)/2; limits 9ε | 10ε | 14ε
c/tf = 78.8/10 = 7.88 vs 9.00 | 10.00 | 14.00
Flange: Class 1
Table 5.2Web (internal, in bending)
c = h − 2tf − 2r; limits 72ε | 83ε | 124ε
c/tw = 134.0/6.5 = 20.62 vs 72.0 | 83.0 | 124.0
Web: Class 1
§5.5.2(6)Section class = least favourable element class
max(flange, web)
max(1, 1)
Section: Class 1
EN 1993-1-1 Table 6.2Buckling curve selection (h/b=0.95, tf=10.0 mm)
curve y-y = b, curve z-z = c
EN 1993-1-1 §6.3.1.3Elastic critical buckling force, both axes
Ncr = π²·E·I/Lcr²
Lcr,y=6000 mm, Lcr,z=6000 mm
Ncr,y=2125.6 kN, Ncr,z=769.2 kN
EN 1993-1-1 (6.50)Non-dimensional slenderness
λ̄ = √(Npl,Rd/Ncr)
Npl,Rd=1265.0 kN
λ̄y=0.771, λ̄z=1.282
EN 1993-1-1 (6.49)Reduction factor χ (imperfection factor α from the curve)
χ = 1/(Φ+√(Φ²−λ̄²)) ≤ 1
αy=0.34, αz=0.49
χy=1.000 (λ̄≤0.2, buckling ignored per §6.3.1.2(4)), χz=1.000 (λ̄≤0.2, buckling ignored)
EN 1993-1-1 (6.47)Buckling resistance, both axes — governing axis controls
Nb,Rd = χ·A·fy/γM1
γM1=1
Nb,Rd,y=1265.0 kN, Nb,Rd,z=1265.0 kN → governs y-y
EN 1993-1-1 (disclosed simplification)Combined axial + bending — linear interaction
N/Nb,Rd + My/Mc,Rd ≤ 1.0
22.6/1265.0 + 72.3/100.9
Ratio = 0.734 → OK

Step values are shown in SI (m, kN, kN·m) regardless of the display-unit toggle.