Episode 21: Dunnage bags load securing – Part 2

Why are there no problems in most cases, even though hardly anyone does the math?

This can be proven on the basis of calculations. Provided that, as described in Part 1, no technical errors are made.

Case studies

What would these barrel pallets do at a rolling angle of 37º?

They would naturally slip or tip over. A rolling period of up to 2-3 times per minute is not unusual. The roll angle of 38º would correspond to the maximum acceleration of 0.8 g transverse to the direction of travel.

Let’s take the classic block of five Euro pallets as an example, as described in Part 1.

The load units weigh 900 kg each and are 1.60 m high. The side length of the two blocks is 2.40 m each.

The question now is, how large must the stowage cushion be so that the force from the load is compensated by 80% of the cushion area?

Calculate the upholstery area:

Side length:
2.40 m x 0.8 = 1.92 m

Height:
1.60 m x 0.8 = 1.28 m

Gap width:
0,34 m

The width of the gap between the loading units results from the internal width of the container of 2.34 m, minus the pallet dimensions of 1.20 m + 0.80 m, i.e. 0.34 m.

Formula for the effective area of a baffle plate

Step 1

The formula contains the width (bDB) as well as the height (hDB) and the gap width (d).

In order to determine the respective initial dimension, the elements of the formula must be rearranged:

(bDB – π * d/2) becomes (bDB + π * d/2) and (hDB – π * d/2) becomes (hDB + π * d/2)

Step 2

The next step is to compare the permissible load on the pad with the force from the load. There must be at least a balance.

The CTU code specifies the following formula for the pad load:

Using the values from the example above, the following results: FDB = 1.92 * 1.28 * 10 * 9.81m/s2 * 0.55 * 0.75 [kN] = 67.77 kN.

The force that this cushion can exert against a load is therefore 6,777 daN.

Step 3

The next step is to calculate the force resulting from the load.

Here are the formulas from the CTU code for a sliding/tilting load. However, it is important to note that the weight is given in tons and not in kilograms as usual.

Inserting the values from the example into the calculation results in the following:

FLoad = 2.7 to * 9.81 m/s2 * (0.8 – 0.3 * 0.75 * 0.2) [kN]
FLoad = 26.45 * (0.8 – 0.045) [kN]
FLoad = 26.45 * 0.755 = 19.97 kN = 1,997 daN

The securing force (6,777 daN) resulting from the stowage cushion is therefore 3.3 times greater than the force (1,997 daN) resulting from the load.

Conversely, this means that if the size of the cushion is selected so that the load is held flat, i.e. cannot tip, slide or turn, the securing force of the cushion is generally always sufficient.

Yours, Sigurd Ehringer

Rothschenk assortment

4 good reasons for Rothschenk

SERVICE

Our customer center has only one goal: to turn your problems into solutions. Whether standard stowage cushions, bestsellers or load securing personally tailored to your needs -. we accompany you consistently from A as in field service to Z as in certification. That is our promise to you, as a leader in our industry.

PROFESSIONAL QUALITY

We attach great importance to professional cargo securing. That is why we have our own production, which ensures reliable operation through modern manufacturing technologies and strict quality control. Thus, we offer our customers a comprehensive and high-quality range of services in the field of transport logistics.

CERTIFICATION

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SUSTAINABILITY

As a load securement company, we are proud to have several certifications that validate our sustainability efforts and our commitment to environmental protection and social responsibility. For you as a purchaser, this means that we demand and promote the implementation of high environmental and social standards both within the company and along the supply chain.

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