tutaj (klik) - Projekt Oversize - Akademia Morska w Szczecinie

The lng angle needed for the lever of the shearing moment to reach the
crical posion depends on the inial height of the centre of gravity and the
dimensions of the cargo base. This relaon is described by the following rule: the
lower the cargo’s centre of gravity and the larger the cargo base are, the more
stable the cargo is. This means that the shearing moment acng on the cargo has
less chance to p over the cargo.
Basic methods of prevenng cargo from pping over are these (Fig. 91):
1. blocking,
2. boundling,
3. increasing the area of cargo base,
4. bracing,
5. lashing.
8.1. Blocking
This method is applicable when cargo packages are of similar shape and size, and
are strong enough to withstand mutual interacon. The packages stowed next to each
other make up a solid block that in an enclosed space of the container cannot move
in any direcon. The cargo unit has to have a construcon adjusted to this method of
securing, in parcular it has to be sufficiently strong to withstand the impact of the
locked cargo. If the dimensions and stowage of cargo packages leave empty spaces,
filler material should be put into such spaces (wood or air cushions).
The blocking method can be used in oversize cargo transport on container
plaorms. In such cases blocking can be executed by using stanchions with spacing
strictly adjusted to the cargo size (Fig. 92).
8.2. Bracing
When braces are used for cargo securing, it is important whether the wood
was cut along or across the growth rings. Wood cut across the rings accepts the
load parallel to its growth rings, which increases the strength of wood. Load forces
at right angle to the rings should be avoided, although nailing in this direcon is
always recommended. For calculaons of maximum load of a single wood baen
the following values should be assumed: 1 cm 2 of wood baen cross-secon may
accept up to 30 kg of load force. In fact, maximum lashing capacity of baens
depends on the direcon of the load force relave to wood rings orientaon:
1. LC = 30 daN/cm 2 for forces exerted perpendicular to the rings
2. LC = 100 daN/cm 2 for forces exerted parallel to the rings.
The higher LC value can only be adopted for calculaons when we are absolutely
sure that the load forces are exerted parallel to the baen wood rings (Fig. 93).
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