Input details
Enter curve and load data
Use one consistent set of project assumptions. The calculator converts supported unit choices internally before evaluating the 90-degree condition.
Worked check
Example Data Table
| Mass | Speed | Radius | Radial g | Raw radial force | Factored radial demand |
|---|---|---|---|---|---|
| 1,250 kg | 12 m/s | 18 m | 0.816 g | 10.00 kN | 16.50 kN |
Calculation method
Formula Used
ar = v² / rGr = ar / gFr = m × v² / rFdesign = Fr × safety factor × (1 + dynamic allowance / 100)
ar is radial acceleration. v is speed. r is centreline radius. g is the selected gravity setting. m is moving mass. The radial g load expresses radial acceleration as a multiple of gravity.
At the 90-degree side position of a vertical path, weight acts tangent to travel. It is shown separately and is not added directly to the radial support demand.
Practical workflow
How to Use This Calculator
- Identify the moving mass at the 90-degree point.
- Enter the actual speed at that location.
- Measure the radius to the mass centreline.
- Apply project-approved safety and dynamic factors.
- Enter radial capacity only when the direction matches.
- Review the radial force, factored demand, and utilization.
- Confirm the final design using governing codes and engineered details.
Design notes
Understanding 90 Degree G Loading
A 90-degree g load calculation helps estimate the radial demand created when a suspended, guided, or moving construction item enters a vertical circular path. The side position is often called the 90-degree point. At this point, the path radius points horizontally. Gravity points vertically. These directions are perpendicular.
The calculator first converts every entry into standard units. Speed becomes metres per second. Radius becomes metres. Mass becomes kilograms. It then calculates radial acceleration from speed squared divided by radius. Dividing that acceleration by local gravity gives the radial g load. Multiplying acceleration by mass gives the radial force.
A smaller radius increases the demand quickly. Doubling speed creates four times the radial acceleration. This is why speed control matters around tight curved paths. The same principle applies to rotating forms, guided hoists, curved conveyors, amusement devices, and temporary lifting arrangements. A large mass also increases force, although it does not change the g value.
At the 90-degree location, gravity is tangential to the motion. It does not directly add to the radial support force. However, gravity still creates a vertical load. The calculator shows this weight separately. It also shows a simple resultant reference value. That value combines radial force and weight as perpendicular components. Use it only where the load path actually transfers both directions.
Safety factors and dynamic allowance improve preliminary planning. The factored radial demand is the raw radial force multiplied by the selected safety factor and dynamic allowance. The resulting number is not a substitute for code-required combinations. Designers must consider connections, fatigue, vibration, bearing pressure, braking, impact, restraint, and actual equipment instructions.
Use measured or manufacturer-approved speed data. Enter the centreline radius, not an outside clearance dimension. Check whether the mass includes attachments, rigging, payload, and water or material carried by the equipment. Select a capacity only when it represents the same radial direction and connection condition.
This tool is useful for early screening and comparison. It does not verify a structural member, foundation, anchor, or lifting device. It does not replace project drawings or jurisdictional rules. A qualified engineer should review any construction work involving people, elevated loads, repeated cycles, or unusual motion.
Confirm the selected units before comparing results across projects. Preserve calculation records, assumptions, and revisions for transparent coordination during design reviews.
Common questions
FAQs
1. What does 90-degree g load mean?
It is the radial acceleration demand at the side point of a vertical circular path. The calculator expresses that acceleration in g units and converts it into radial force using the moving mass.
2. Why is the path position fixed at 90 degrees?
At this position, gravity is perpendicular to the radius. That makes the radial support demand easier to isolate. It is useful for a specific side-point screening check.
3. Does gravity add directly to radial force here?
No. At the 90-degree side position, gravity acts tangent to motion. The calculator still reports weight because supports and connections may transfer both radial and vertical actions.
4. Why does speed have such a large effect?
Radial acceleration uses speed squared. Increasing speed by two times increases radial acceleration and radial force by four times when mass and radius remain unchanged.
5. Which radius should be entered?
Use the radius from the curve centre to the moving mass centreline. Avoid using outside clearance dimensions unless they match that actual travel radius.
6. What safety factor should I use?
Use the factor required by the governing design method, equipment instructions, and project risk assessment. This calculator applies the value you enter but does not choose it for you.
7. What is dynamic allowance?
Dynamic allowance is an added percentage for effects such as impact, operating variation, or uncertainty. Apply it only when justified by your project method and equipment behaviour.
8. What capacity belongs in the optional field?
Enter an approved radial capacity for the same member, connection, direction, and condition. Do not compare a vertical-only rating with a factored radial force.
9. Can this be used for a horizontal turn?
The radial acceleration formula still applies. However, the 90-degree vertical-path explanation does not. Gravity and support directions must be reviewed for the actual horizontal configuration.
10. Can I mix metric and imperial entries?
Yes. The available mass, speed, radius, and capacity options are converted internally. Review each displayed unit carefully before using a result in project documentation.
11. Is this result suitable for final structural approval?
This is a preliminary screen, not a final design. Always use verified inputs before obtaining qualified engineering approval.