Xponexus Engineering

Steel Column Base Plate Design Tool

Comprehensive Eurocode EN 1993-1-8 / EN 1992-1-1 calculator for exposed and grouted steel column base plates under combined axial load, biaxial bending and shear. Includes plate yielding, concrete bearing, anchor bolt tension/shear, weld adequacy and grout checks.

EN 1993-1-8 EN 1992-1-1 Biaxial bending Anchor bolts Bearing pressure Weld check

Weld check Grout/shim check Shear key/friction

Scope note:
Preliminary design assistant aligned with EN 1993-1-8 §6 and EN 1992-1-1 §6.7. Always verify with National Annex parameters, project-specific geotechnical data, and detailed connection drawings.

Column & Base Plate Geometry

Define column section, plate dimensions and eccentricity.

Geometry

Column section Column type Column depth h (mm) Flange width b (mm) Web thickness tw (mm) Flange thickness tf (mm) Root radius r (mm)

For CHS enter diameter as h and wall as tw. Ignored for custom.

Base plate Plate length L_p (mm) Plate width B_p (mm) Plate thickness t_p (mm) Plate steel grade f_y,plate (MPa) γM0 (plate)

Plate yield from grade auto-populates; override manually if needed.

Overhang & projection Overhang c_x along length (mm) Overhang c_y along width (mm) Auto-compute overhangs? Eccentricity e_x (mm) Eccentricity e_y (mm)

Eccentricity = moment/axial. Positive = tension on far bolt row.

Design Actions (ULS)

Applied ULS forces and moments at column base.

Actions

Axial & moment N_Ed (kN) N_Ed type M_Ed,x (kNm) – major axis M_Ed,y (kNm) – minor axis V_Ed,x (kN) – shear along x V_Ed,y (kN) – shear along y

Load combination Governing combination Second-order amplification (η) Uplift load N_uplift (kN) Minimum N_Ed (kN) – for bolt tension

Min NEd is used for the bolt tension LC (max uplift scenario).

SLS / serviceability actions N_SLS (kN) M_SLS,x (kNm) M_SLS,y (kNm) Allow SLS bearing check?

SLS bearing stress ≤ f_jd,SLS = 0.67 f_ck.

Concrete Foundation & Grout

Concrete grade, pad geometry, joint material and bearing factors.

Foundation

Concrete pad Concrete grade f_ck (MPa) Pad length a (mm) Pad width b (mm) Pad depth d (mm) γc (concrete)

Bearing & joint βj (joint coefficient) αcc (long-term factor) Grout type Grout thickness t_g (mm) Grout f_ck (MPa) Levelling tolerance (mm)

Grout included in joint design per EN 1993-1-8 §6.2.5.

Concentration factor a₁ (pad length for kj) b₁ (pad width for kj) Auto kj from pad geometry? k_j (override, 0=auto)

kj = √(a₁·b₁ / (Lp·Bp)) ≤ 5.0 per EN 1992-1-1 §6.7.

Anchor Bolts

Bolt layout, grade, embedment and design resistances.

Bolts

Bolt arrangement Bolt pattern No. of bolts n Bolt PCD along x – p_x (mm) Bolt PCD along y – p_y (mm) Bolt diameter d (mm) Bolt dia custom (mm, 0=from list)

Bolt grade & material Bolt grade f_ub (MPa) f_yb (MPa) γM2 (bolt) Tensile stress area A_s (mm²) Auto As from diameter?

Embedment & pull-out Effective embed. h_ef (mm) Bolt type Edge distance c_min (mm) Bolt spacing s (mm) Concrete cone factor k_c γMc (anchor)

Cone resistance: N_Rk,c = kc·fck^0.5·hef^1.5.

Column-to-Plate Weld

Fillet weld sizing around column perimeter (EN 1993-1-8 §4).

Weld

Weld geometry Weld type Throat a_w (mm) Weld around perimeter? Weld length L_w (mm, 0=auto) Auto weld length from section?

Weld material Electrode class f_u,weld (MPa) β_w (correlation factor) γM2 (weld)

Directional method per EN 1993-1-8 §4.5.3. βw for S355 = 0.90.

Force distribution to weld Weld design method Normal stress σ⊥ override (MPa, 0=auto) Shear stress τ∥ override (MPa, 0=auto)

Auto derives weld stresses from NEd, VEd and weld throat area.

Shear Transfer Mechanism

Friction, shear key or bolt bearing for horizontal shear resistance.

Shear

Friction at interface Friction coefficient μ Surface condition γM3 (friction)

F_friction,Rd = μ · N_Ed / γM3.

Shear key (if required) Provide shear key? Key depth d_k (mm) Key width w_k (mm) Key length l_k (mm) Key steel grade f_y,key (MPa)

Bolt shear at interface Bolts resist shear? Bolt hole clearance (mm) No. of shear bolts n_s α_v (shear factor)

V_Rd,bolt = αv · fub · As / γM2 per bolt.

Stability, SLS & Notes

Bearing pressure distribution, plate stiffness and project notes.

SLS / Notes

Bearing pressure method Analysis method Limit eccentricity check? Allow biaxial bearing?

Plate flexibility Effective cantilever c (mm, 0=auto) Plate class Add stiffeners? Design notes

Check Summary

Press "Run calculations" to evaluate.

ULS + SLS

Concrete bearing

—

Plate yielding

—

Bolt tension

—

Bolt pull-out

—

Shear resistance

—

Weld

—

Grout/bearing

—

SLS bearing

—

Governing failure mode: —
PASS/FAIL based on worst utilisation ≥ 1.0.

Detailed Design Report

Intermediate values for transparency and verification.

Press "Run calculations" to generate report...