Pole Loading Calculator

Inputs

Units: mm for sizes, m for height, kPa for wind, kN for loads.

Pole shape

Controls projected area and section formulas.

Section type

Hollow requires wall thickness.

Outer size (mm)

Diameter (circular) or width (square).

Wall thickness (mm)

Ignored for solid sections.

Exposed height (m)

Cantilever length for moment and deflection.

Wind pressure (kPa)

kPa equals kN/m^2.

Drag coefficient (pole)

Typical: 1.0–1.4 for round members.

Equipment projected area (m^2)

Antennas, signs, fixtures, brackets.

Drag coefficient (equipment)

Use higher values for bluff attachments.

Additional point lateral (kN)

Cable pull, impact, or attachment reaction.

Vertical top load (kN)

Fixture weight transferred to pole.

Eccentricity of vertical load (m)

Creates an added moment: V * e.

Material

Defaults update when you recalculate.

Steel grade (if applicable)

Used only for steel defaults.

Yield strength (MPa)

Override if you have tested values.

Elastic modulus E (MPa)

Affects deflection only.

Safety factor

Allowable = strength / factor.

Deflection limit ratio (L/ )

Common: 50–100 depending on use.

Reset

Example data table

Use this sample to verify the calculator output flow.

Scenario	Shape	Outer (mm)	t (mm)	Height (m)	Wind (kPa)	Equip area (m^2)	Extra lateral (kN)	Base moment (kN*m)	Top defl (mm)
Lighting pole	Circular hollow	219.1	6.0	8.0	1.0	0.35	0.0	~ 7.0	~ 14
Sign support	Square hollow	250	8.0	10.0	1.2	1.00	1.5	~ 23	~ 25
Utility pole	Circular solid	300	n/a	12.0	0.9	0.60	0.5	~ 31	~ 18

Example outputs are illustrative and depend on coefficients and material inputs.

Formula used

Wind forces

F_pole = q * C_d,pole * (b * L)
F_equip = q * C_d,equip * A_equip
H_total = F_pole + F_equip + F_add

q is wind pressure (kN/m^2). b is diameter/width (m). L is exposed height (m).

Base moments

M_pole = F_pole * L / 2
M_top = (F_equip + F_add) * L
M_ecc = V_top * e
M_total = M_pole + M_top + M_ecc

Uniform wind is treated as a distributed load. Point loads act at the pole top.

Section properties

Circular solid: Z = pi*D^3/32, I = pi*D^4/64
Circular hollow: Z = pi*(D^4-d^4)/(32D), I = pi*(D^4-d^4)/64
Square solid: Z = b^3/6, I = b^4/12
Square hollow: Z = (b^4-bi^4)/(6b), I = (b^4-bi^4)/12

All section dimensions are in mm to match stress units (MPa = N/mm^2).

Stress and deflection checks

Bending stress: sigma = (M_total * 10^6) / Z
Allowable bending: sigma_allow = f_y / FS
Deflection (uniform): delta_w = w*L^4 / (8EI)
Deflection (end load): delta_P = P*L^3 / (3EI)

M in kN*m converts to N*mm using 10^6. Deflection is reported in mm.

How to use this calculator

Choose the pole shape and whether the section is solid or hollow.
Enter outer size, thickness (if hollow), and the exposed height.
Set wind pressure and drag coefficients to match your exposure.
Add equipment projected area and any extra point lateral load.
Include vertical load and eccentricity if fixtures offset the centerline.
Pick material properties and a safety factor, then calculate.
Use the CSV/PDF buttons to share results with your team.

This tool is a simplified check. For critical structures, apply your governing design standard and confirm foundation, connections, and load combinations.

Load Inputs and Assumptions

The calculator treats the pole as a vertical cantilever with lateral wind pressure and optional top point loads. Wind pressure is entered in kPa, which equals kN/m². Pole wind is modeled as a uniform load over the exposed height, while equipment wind and any added lateral are applied at the top to represent a conservative worst case. For preliminary sizing, compare scenarios by changing wind, height, and section type without altering units quickly.

Wind Pressure and Drag Coefficients

Wind force is computed from F = q × C_d × A. Projected area for the pole uses diameter or width (m) multiplied by height (m). Typical drag coefficients often fall between 1.0 and 1.4 for round members, while attached items may be higher due to bluff geometry. Enter the equipment projected area directly to capture antennas, signs, luminaires, and brackets.

Moment Demand and Critical Section

Base moment combines the distributed wind resultant at mid-height and top actions at full height: M = F_poleL/2 + (F_equip+F_add)L. If a vertical top load is offset from the centerline, an eccentricity moment V × e is added. The displayed total base moment is the governing demand for bending checks.

Stress, Utilization, and Safety Factor

Bending stress uses section modulus: σ = (M × 10⁶)/Z in MPa. Allowable stress is taken as yield strength divided by the selected safety factor. Utilization is the ratio of calculated to allowable; values at or below 1.00 indicate a pass for that check. A simple shear check is also provided using cross-sectional area as a quick screening metric.

Deflection Limits and Serviceability

Top deflection is estimated from classic cantilever formulas for a uniform load and an end load: δ = wL⁴/(8EI) + PL³/(3EI). The serviceability limit is expressed as L divided by a user-entered ratio (for example, L/60). Lower ratios allow more movement; higher ratios tighten drift control for lighting, signage visibility, and connection comfort.

FAQs

1) What wind pressure should I enter?

Use the design wind pressure from your governing code or project criteria, expressed in kPa. If you only have wind speed, convert it to pressure using the code method for your terrain and importance category.

2) Where does equipment load act in the model?

Equipment wind and any added lateral are applied at the pole top to produce a conservative base moment. If the attachment is lower, you can approximate by reducing the exposed height to the attachment elevation.

3) What does the safety factor change?

The safety factor reduces the allowable stress: allowable equals material strength divided by the factor. Increasing it lowers allowable values and raises utilization, which is helpful for conservative screening.

4) Why is there an eccentricity input?

If the vertical top load is offset from the pole centerline, it creates a bending moment equal to V times e. This can be significant for side-mounted luminaires, signs, and bracketed hardware.

5) How is deflection estimated?

Deflection is computed using elastic cantilever formulas for a uniform lateral load plus an end load. It assumes small deflections, linear material behavior, and a fixed base at the foundation interface.

6) Does this check foundation and anchors?

No. The results focus on pole member demand, stress, and drift. You must separately verify base plate, bolts, embedment or footing design, and all governing load combinations.