The inertia force is due to inertia during transport, it causes lateral displacements forward or backward. If the load were to move, the force would cause a movement that would cause the weight of the load to be much greater than its actual weight. To determine the weight of the load at a moment when the inertia force is acting (a collision, braking, acceleration, etc.) one must proceed by calculating :
Acceleration (a)
It is calculated by the following formula:
- a = cx-cy-cz-g
where:
a = acceleration
cx, cy, cz = acceleration coefficients
| Longitudinal cx | Transversal cy | Vertical cz |
| Forward 0.8 | Left 0.5 | Downward |
| Back 0.5 | Right 0.5 | 1 |
The frictional force Fr is the resistance offered by one body when rubbing against another. Its value is obtained as follows:
Fr = m-g-μ
where:
m = mass of the load
g = acceleration of gravity (9.81 m/s2)
μ = friction coefficient, variable depending on the nature of the load and the surface of the vehicle.
INSHT, nº1.038 2015 Fastening devices for work equipment and miscellaneous loads on transport vehicles: Safety.
The holding force Fs is the force that must be applied to the load to keep it stable and at rest in order to prevent it from moving during transport.
Its formula is:
Fs=Fp - Fr
( The friction factor between different materials, support surfaces and in situations with snow, ice and wet conditions must be taken into account ).
