Analyze mast loads, moments, and section response accurately. Export results to CSV and PDF reports. Support faster field planning and safer structural installation decisions.
| Case | Point Load (kN) | Load Height (m) | UDL (kN/m) | UDL Start (m) | UDL Length (m) | Top Moment (kN.m) | Base Moment (kN.m) |
|---|---|---|---|---|---|---|---|
| Mast A | 4.0 | 8.0 | 0.45 | 0.0 | 10.0 | 0.0 | 54.5 |
| Mast B | 6.0 | 12.0 | 0.60 | 2.0 | 8.0 | 5.0 | 105.8 |
| Mast C | 2.5 | 6.0 | 0.30 | 0.0 | 6.0 | 3.0 | 23.4 |
Point load moment: Mp = P × h
Distributed load resultant: Rw = w × L
Distributed load moment: Mw = (w × L) × (a + L/2)
Total unfactored base moment: M = Mp + Mw + Mt
Factored base moment: Mu = Load Factor × M
Tube second moment of area: I = π/64 × (D4 − d4)
Section modulus: Z = I ÷ (D/2)
Bending stress: Stress = Mu ÷ Z
Tip deflection: estimated by numerical integration of the cantilever moment diagram along the mast height.
Where P is point load, h is its height, w is distributed load intensity, L is distributed load length, a is distributed load start height, D is outer diameter, and d is inner diameter.
A mast in construction often behaves like a cantilever member. It resists wind, equipment loads, signage forces, cable pull, and installation loads. This mast bending moment calculator helps estimate the base moment created by those actions. It also shows bending stress, base shear, section modulus, and tip deflection.
Base bending moment is one of the key design checks for a steel mast. It affects the mast shaft, base plate, anchor bolts, welds, and foundation. A larger moment increases stress and can raise serviceability issues. Deflection also matters because excessive movement can affect alignment, cladding, fixtures, and safety clearances.
This calculator handles three common actions. The first is a lateral point load applied at a chosen height. The second is a distributed lateral load over a selected mast segment. The third is a direct top moment. Together, these create the total unfactored base moment. A load factor then produces a factored design moment.
The tool uses a hollow circular mast section. It calculates the second moment of area and section modulus from the entered diameter and wall thickness. Those properties convert bending moment into stress. The utilization ratio compares calculated stress against the entered yield strength. This helps users make a quick screening check before detailed structural design.
Construction teams can use this page during planning, temporary works review, tower accessory checks, lighting mast studies, and equipment support assessments. It is also useful when comparing alternate mast sizes. Small changes in load height can strongly increase moment demand. That is why the application height fields are important.
Use realistic load cases and keep units consistent. Check wind criteria, code combinations, connection capacity, fatigue, local buckling, and foundation behavior separately. This tool is best used for preliminary evaluation, design comparison, and reporting. Final structural approval should always come from a qualified engineer using project-specific standards and verified load data.
Mast bending moment is the turning effect created by lateral loads acting at a distance from the mast base. It is usually highest at the base of a cantilever mast.
Include all relevant lateral actions such as wind pressure, equipment pull, cable loads, mounted fixtures, and any top-applied moment. Use load cases that match your project conditions.
Moment equals force multiplied by distance. The higher the load acts above the base, the larger the bending moment becomes. Small height changes can create significant demand increases.
It is the elevation where the continuous lateral load begins. This is useful when only part of the mast carries wind pressure, cladding, cable trays, or attached equipment.
No. It checks mast moment, stress, shear, and deflection only. Base plate design, anchor tension, welds, local buckling, dynamic response, and foundation checks still need separate review.
Section modulus links bending moment to bending stress. A larger section modulus usually lowers stress for the same load case, which helps compare alternate mast sizes quickly.
The page uses numerical integration of the cantilever moment diagram. It combines point load, partial distributed load, and top moment effects to estimate tip movement.
Enter height in meters, loads in kilonewtons, distributed load in kilonewtons per meter, diameter and thickness in millimeters, modulus in gigapascals, and strength in megapascals.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.