BS/EN 13001-2-2014 pdf download.Crane safety – General design Part 2 : Load actions.
The buffer forces shall be calculated from the kinetic energy of all relevant parts of the crane. Generally speeds from 0.7 to 1 times the nominal speed should be used, Lower values than 0.7 may be used where they are justified by special measures such as the existence of a redundant control system for retarding the motion.
The buffer forces shall be calculated taking into account the distribution of relevant masses and the buffer characteristics. Where the crane or the trolley is restrained against rotation about the vertical axis (e.g. bridge crane with guide rollers on one rail) and its structure is stiff, the buffer deformations may be assumed to be equal; in that case. if the buffer characteristics are similar, the buffer forces will be equal.
In calculating buffer forces, the effects of suspended loads that are unrestrained horizontally (free to swing) need not be taken into account. However when the travel speed is reduced before collision with the buffers, it is possible that the load sway forward is near its maximum amplitude simultaneously with compression of the
buffers. In this case the hoisted mass multiplied by the deceleration used before reaching the buffers should be added as a horizontal load.
4.2.4.5 Loads due to tilting forces
If a crane with horizontally restrained load (e.g. stiff masted crane or limited swing crane) or its trolley can tilt when it, its load or lifting attachment collides with an obstacle, the resulting forces shall be determined.
If a tilted crane or trolley can fall back into their normal positions uncontrolled, the resulting impact on the supporting structure shall be taken into account.
4.2.4.6 Loads caused by emergency cut-out
Loads caused by emergency cut-out shall be calculated in accordance with 4.2.2.5 taking into account the most unfavourable state of drive (i.e. the most unfavourable combination of acceleration and loading) at the time of cut-out.
For indirectly acting lifting force limiters the F1 represents the maximum load In the hoist system after the triggering has operated and the hoist motion is brought to rest. Annex C indicates a method of calculation for the factor for indirectly acting lifting force limiters.
For any crane and application with an indirectly acting lifting force limiter, the value of the factor shall not be less than q4. = 1,25. For any crane and application with a directly acting lifting force limiter, the value of the factor #1 shall not be less than L = 1,4.
Where due to nature of the application or the construction of the load lifting attachment it is foreseeable, that jamming of the load can occur, this shall be taken into account in the calculation of the force Such applications can be e.g.
— unloading of containers from ships,
— all load handling operations, where the load lifting attachment is capable of taking loads greater than the rated load of the crane, e.g. scrap metal handling or load lifting attachments relying on magnets.
4.2.4.8 Loads due to dynamic cut-off of radial movement by lifting moment limiter
The lifting moment limiter stops the radial movement of the load, when this passes beyond the lifting radius that corresponds to the rated moment. The radial over travel, by which the load exceeds the limit radius, depends upon the characteristics of the radius control of the luffing movement, the braking arrangement and the delays in the braking system.
The load actions due to exceeding the limit radius shall be taken into account in the proof of competence calculations. The loadings caused both by the handled load and by the dead weight of radially moving parts of the crane, shall be taken into account.BS/EN 13001-2-2014 pdf download.