COLUMN BASE PLATE DESIGN CALCULATOR
Design according to Eurocode 3
Column Properties (H-section)
dcol = mm Column depth
bf = mm Column flange width
tf = mm Column flange thickness
tw = mm Column web thickness
Icol = mm⁴ Column moment of Inertia
Figure 1: Geometry
Base Plate Dimensions
Base Plate Properties
Lbp = mm Base plate length (in the direction of bending)
Bbp = mm Base plate width
tbp = mm Assumed base plate thickness
fyp = MPa Base plate yield strength (e.g., S355 steel)
Concrete Pedestal/Foundation Properties
Lconc = mm Concrete foundation length
Bconc = mm Concrete foundation width
fck = MPa Concrete compressive strength
Loads (factored)
P = kN Axial compression force
V = kN Shear force
M = kN·m Bending moment
Anchor Bolt Properties (Assuming 4 bolts)
db = mm Bolt diameter
fub = MPa Bolt ultimate strength (e.g., Grade 8.8)
As = mm² Tensile stress area (e.g., M24 bolt)
nbolts = Total number of bolts
eb = mm Edge distance for bolts
fc,bearing,design = 0.6·fck = 18.00 MPa Design concrete bearing strength
A1 = Lbp·Bbp = 180000 mm² Base plate area
A2 = Lconc·Bconc = 360000 mm² Concrete foundation area
Aratio = √(A2/A1) = 1.41 Area ratio
fc,bearing,allowable = min(fc,bearing,design·Aratio; 1.7·fck) = 25.44 MPa Allowable bearing stress
ecc = M/P = 83.33 mm Eccentricity of the axial load
This case is more complex and requires iterative methods or simplified approximations
The simplified method below assumes a triangular pressure distribution and calculates tension in the bolts.
ex = Lbp/2 − ecc = 141.67 mm Distance to resultant compression
pmax,comp = P/(Bbp·(3·ex)) = 2.82 MPa Maximum bearing pressure
Bearing Check: pmax,comp ≤ fc,bearing,allowable = 1 [1 = Ok; 0 = Not Ok]
Tbolt = P·(Lbp/2 − ex)/(Lbp/2 − eb) = 424.66 kN Tension in anchor bolts
Bolt Tension Check: Tbolt ≤ 0.9·fub·As = 1 [1 = Ok; 0 = Not Ok]
tplate,req,tension = √(6·Tbolt·(Lbp/2 − eb)/(0.9·fyp·Bbp)) = 25.30 mm Required plate thickness for tension
Plate Thickness Check: tbp ≥ tplate,req,tension = 1 [1 = Ok; 0 = Not Ok]
μ = Coefficient of friction for steel on grout
Vfriction = μ·P = 240.00 kN Shear resistance from friction
Vbolt = |V − Vfriction| = 0.00 kN Shear to be resisted by bolts
Vbolt,cap = nbolts·0.9·0.6·As·fub/1000 = 611.81 kN Bolt shear capacity
Bolt Shear Check: Vbolt ≤ Vbolt,cap = 1 [1 = Ok; 0 = Not Ok]
Column Section: H-Section
Base Plate Check
Base Plate Thickness = 50 mm
Required Plate Thickness = 25.30 mm
Plate Thickness Check: 1 [1 = Ok; 0 = Not Ok]
Concrete Bearing Check
Max Bearing Pressure = 2.82 MPa
Allowable Bearing Pressure = 25.44 MPa
Bearing Check: 1 [1 = Ok; 0 = Not Ok]
Shear Transfer Check
Shear Transferred by Friction = 240.00 kN
Remaining Shear for Bolts = 0.00 kN
Bolt Shear Check: 1 [1 = Ok; 0 = Not Ok]