Episode 33: Problem treatments – using blocking agents correctly

The most common means of transportation in Europe today is the semi-trailer.

Compared to articulated trucks, it has the advantage of a continuous loading area, a larger payload and it is easier to maneuver.

In this article, I will discuss problem treatments in connection with securing devices for this type of structure.

The major manufacturers such as SchmitzCargobull, Krone and Kögel build their trailers with comparable loading dimensions.
The loading width is predominantly 2.48 m, the loading length 13.60 m and the loading height 2.70 m.

Deviations are possible depending on the body type, but are irrelevant for the problem presentation.
The inner drawer width is based on the dimensions of the Euro pallet.

The stowage pattern

The congestion pattern can be illustrated using the adjacent graphic. With an inner drawer width of 2.48 m, this results in a total gap of 8 cm, divided into 3 or 4 gaps, depending on how stowage is carried out.
The maximum number of pallets can also be calculated from this diagram.

Stowed lengthwise:
13.60 m / 1.20 m * 3 = 33 pallets

Stowed crosswise:
13.60 m / 0.80 m * 2 = 34 pallets

Lengthways or crossways is up to the observer, depending on whether he is arguing as a truck or forklift driver.

The payload

The technical payload of 27,000 kg specified in the certificates for the standard semi-trailer for calculating the body strength is of course not the weight that can be expected when loading.

The practical payload is the weight that can be loaded without overloading the vehicle. As an example, 25,500 kg can be calculated.

However, each company must determine this weight itself in order to have a reliable basis for planning, as this depends on various factors. For example, if the load weight can change within limits due to production.

To take the considerations further, the practical payload of 25,500 kg can be divided by the number of pallets. Calculated with 33 pallets, the average weight per pallet is 773 kg or with 34 pallets 750 kg.

As soon as the load units exceed this weight, the semi-trailer can no longer be fully loaded because it would otherwise be overloaded.

The following loading units are typical examples:

• Octabins
• Bigbags
• Beverage pallets with 40 crates
• Bagged goods with cement
• IBCs etc.

Conclusion on load securing

This means that in this constellation the truck is not completely full and the distance to the rear portal is greater than 15 cm. It may also be necessary to move the load away from the bulkhead and back due to the load distribution. At this point it is necessary to think about the way in which the load is secured.

There are only two variants:

1. The vehicle is equipped with on-board securing devices, such as locking beams, whose total securing force must be at least 30% of the technical payload, or
2. It must be secured using conventional securing methods as described in VDI 2700ff.

Unfortunately, in practice the semi-trailer is often only equipped with clamping boards (intermediate wall locks) with a blocking force of just 400 daN, or in the box body with clamping rods with a blocking force of 150 daN. In most cases, this is not enough.

I would like to point out to all vehicle owners that §30StVO obliges them to equip their vehicles with safety devices. Their total securing forces should amount to at least 30% of the technical payload. If this is not the case, problems with load securing are inevitable.

Examples of securing devices and their blocking force

Clipboard (partition closure)
Friction-dependent
Blocking force as good as new 400daN

Clamping beam
Friction-dependent
Blocking force as good as new 800-1,000daN

Barrier bar
Vehicle-specific | positive locking
Blocking force as good as new 1,000 – 4,500daN

Clamping rods
Friction-dependent
Blocking force as good as new 150daN

Conclusion

It is therefore important that the responsible shipper thinks about how he wants/needs to secure his load before procuring transport space.

The vehicle-side, system-typical securing devices generally have the greatest securing forces. The means that can be used in different vehicle variants are often weaker.

If the above-mentioned variant 1 is not possible or cannot be implemented, variant 2 must be used. Variant 1 are securing devices that represent a form-fit securing method. As a rule, it is the simplest, safest and quickest method of securing the load.

The description of variant 2 will appear in one of the next LaSi blogs.

A good approach is to create a vehicle/equipment specification that is company-specific:

• Vehicle type/body type
• Type and design of the vehicle’s systemic securing devices
• Type and number of tension belts, edge protectors and anti-slip mats
• Other required equipment

In another installment of the LaSi blog, I will discuss other special loads that can lead to the so-called domino effect.

Yours, Sigurd Ehringer

Tobias Kreft