What is the EN 1993-1-8 effective area method for baseplate design?

The effective area method per EN 1993-1-8 §6.2.5 defines the effective bearing area A_eff under a column baseplate using a T-stub effective cantilever length c = t_p·√(fy/(3·f_jd·γM0)). The bearing resistance is N_Rd = f_jd · A_eff, where f_jd = β_j · k_j · fcd is the design bearing strength of the grout/concrete interface.

How is the concrete bearing strength f_jd calculated for a baseplate?

Per EN 1993-1-8 §6.2.5(7): f_jd = β_j · k_j · fcd, where β_j = 2/3 (grout/joint factor), k_j = √(A_c1/A_c0) ≤ 3.0 is the area concentration factor from EN 1992-1-1 §6.7 (ratio of foundation footprint to plate area), and fcd = fck/γC is the concrete design strength.

How does EN 1993-1-8 handle combined N_Ed + M_Ed loading on a baseplate?

Per EN 1993-1-8 §6.2.8, the governing case depends on eccentricity e = M_Ed/N_Ed. If e ≤ L_p/6 (kern), the full plate is in compression and no anchor tension is required. For large eccentricity (e > L_p/6), anchor bolts carry tension F_t,Ed and the moment resistance is M_Rd = F_t,anchor,Rd · z_eff, where z_eff is the lever arm from the compression centroid to the anchor bolt row.

What checks does a column baseplate design calculator perform?

A complete EN 1993-1-8 baseplate design check covers: (1) concrete bearing utilisation N_Ed/N_Rd §6.2.5, (2) moment capacity M_Ed/M_Rd §6.2.8, (3) anchor bolt tension F_t,Ed/F_t,Rd per Table 3.4, (4) concrete pull-out cone per EN 1992-4 §7.2, (5) shear transfer via friction μ·N_c + anchor shear §6.2.2, and (6) column flange/web to plate fillet weld §4.5.3.

Gratis Kolomvoetplaat Rekentool — EN 1993-1-8 §6.2.8

Kolomdoorsnede

Staalsoort

Nationale Bijlage

Voetplaatgeometrie

L_p (mm)

B_p (mm)

t_p (mm)

a_w weld (mm)

Fundering

L_f (mm)

B_f (mm)

Betonkwaliteit

Ankerbouten

Ankerklasse

Ankerdiameter

n anchors (tension side)

h_ef (mm)

e_anchor — edge dist. from plate edge (mm)

Rekenwaarden Belasting

N_Ed (kN) — druk + / trek −

M_Ed (kN·m) — buigend moment

V_Ed (kN) — dwarskracht

N_Ed negative = uplift (tension). Set N_Ed < 0 for pure uplift case.

Orange = baseplate Green = effective T-stub area Blue = anchor bolts

Rekenresultaten

39%

PASS ✓

⚠ Gedeeltelijke druk — ankerbouten kunnen worden gemobiliseerd — e=160 mm

EN 1993-1-8 §6.2.5 + §6.2.8 — Key Intermediates

f_jd = β_j·k_j·f_cd 22.22 N/mm²

α=1.667 k_j=1.667 β_j=0.67 f_cd=20 MPa

c = t_p·√(f_yp/(3·f_jd·γ_M0)) 50.78 mm

A_eff (effective bearing area) 69276.73 mm²

Normaalkrachtweerstand N_Rd = f_jd·A_eff 1539.48 kN

Lever arm z_eff 371.5 mm

Ankerbout trekweerstand F_t,Rd (total) 813.31 kN

Uittrekkegel weerstand N_Rd,c (total) 1240.9 kN

Momentweerstand M_Rd 302.15 kN·m

Utilisation Checks — EN 1993-1-8 §6.2.5 + §6.2.8

Controle	Weerstand	Belasting	η	Beoordeling
Concrete bearing (§6.2.5)	1539.48 kN	500 kN	32.5%	✓ PASS
Moment capacity (§6.2.8)	302.15 kN·m	80 kN·m	26.5%	✓ PASS
Anchor bolt tension (Table 3.4)	813.31 kN	6.73 kN	0.8%	✓ PASS
Anchor pull-out cone (EN 1992-4)	1240.9 kN	6.73 kN	0.5%	✓ PASS
Shear transfer (friction + bolts)	1234.42 kN	50 kN	4.1%	✓ PASS
Column-to-plate weld (§4.5.3)	220.68 N/mm²	85.98 N/mm²	39%	✓ PASS

§6.2.5(7): f_jd = β_j·k_j·fcd, β_j = 2/3, k_j = α = min(√(A_c1/A_c0), 3) per EN 1992-1-1 §6.7 · §6.2.8: M_Rd = F_t,anchor·z_eff · EN 1992-4 §7.2: N_Rk,c = 8.9·fck^0.5·h_ef^1.5

Rekenrapport exporteren

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Gerelateerde tools

→ Ankerbout Berekening — NEN-EN 1992-4 →

→ Boutcapaciteit — NEN-EN 1993-1-8 Tabel 3.4

→ Lasnaad Bemessung — NEN-EN 1993-1-8 §4.5

→ Balk Momentweerstand — NEN-EN 1993-1-1

→ Lasplaat Verbinding

→ End Plate Moment Connection

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NEN-EN 1993-1-8 Kolomvoetplaat Rekentool