13.9.1   General comments on mechanical influences in container transport
Since container transport involves multimodal carriage, the goods carried in this manner are also subject to the various stresses of the individual means of transport. When evaluating stresses, the container should be viewed as being a replacement for the cargo/load carrying area of the particular means of transport, such as case body on a truck, a freight car in a train or a ship's hold in maritime transport.
Any problems which occur in these means of transport will occur in the container too. The most frequent misconception is to view the container as a replacement for packaging, an error which repeatedly causes major losses or even jeopardizes the means of transport. The fact that, for example, a standard container is being used does not make it possible to cut down on either load/cargo securing measures or packaging.
The one exception to this is the stackability of packages. Since the container acts as a "hold" which has been designed so as to be carried in stacks in ships, packaging requirements can be simplified in that the packaging need now only be intended to withstand the stack pressures within the interior of a single container, rather than the stack pressures of 8 to 10 m of overstowed cargo in the ship's hold.
This only applies to goods which are only transported in a container and do not undergo any pre- or post-carriage operations.
If, due to their mass or dimensions, packages are not overstowed in the container, packaging requirements are simplified as the packages are not exposed to any stack pressure. In this case, the packaging serves "only" to protect the cargo and, if necessary, to permit cargo securing.
Packaging, stowage and cargo securing in the container must be carried out such that they
  • can withstand the stresses of each individual leg of the journey and
  • can withstand the stresses of the individual means of transport used during the various legs of the journey.
The frequent, physical handling operations (e.g. transfer of cartons, cases, bales etc. from a truck onto a rail freight car, ocean-going vessel, inland waterway vessel and back onto a truck), which exposed the cargo to considerable risk of damage, have been replaced by much gentler container handling operations. Thanks to its standardized dimensions, the container as a cargo unit also benefits from standardized handling, a very high percentage being carried out by container bridges with spreaders.
However, when containers are being packed, higher levels of stress frequently occur than was the case with conventional packing. Since closed standard containers are very frequently selected on cost grounds, goods have to be pushed into the containers and pulled out again during stripping (unpacking) due to their dimensions of mass. This is necessary because crane packing is not possible or the floor loading capacity would be exceeded if industrial conveying equipment were to be used.

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