BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Date
Region
19 January 2018
Page
1/11 Sap nr.
Europe
Rev.
00
60000154301
Forces on cargo and lashing during transport
This guideline describes the forces generally taken in to consideration for a cargo transported by Mammoet,
to verify if the cargo, lashing and support points are suitable for the planned transport.
This guideline provides the magnitude of internal and external forces to be taken in to account when
checking the cargo and its lashing points. It will also offer an insight in reasons for lashing
Conditions / Description of situation
- This document is meant as a reference for engineers who need to verify cargo to be transported
Readers should have basic knowledge of hydraulic trailers and their suspensions system.
- Details of support construction of hydraulic trailers and the trailer calculations are not discussed in
this document. For this please refer to document 020201001
00
For information
only
19 January
2018
Rev.
Description
Date
JVri
Wvern
Wvern
902127
9000021
9000021
Approved
(By subject matter expert)
Owner
(For questions)
Author
Without authorized signature(s) this document is uncontrolled, not binding and for indicative purposes only
NOTE
THIS DOCUMENT IS PREPARED ON THE BEST KNOWLEDGE AT THE TIME OF WRITING AND SUBJECTED TO
NEW INSIGHTS. FOR ALTERATIONS CONTACT THE OWNER
Status For information only
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Contents
Date
Region
19 January 2018
Page
2/11 Sap nr.
Europe
Rev.
00
1 Guideline forces on cargo and lashing
3
2 External forces acting on cargo
2.1 Accelerations
4
4
2.1.1
2.1.2
2.1.3
2.2
2.3
Low speed
Average speed
High speed
Wind forces
Inclinations
4
4
4
5
5
3
Internal forces within open trailer configuration
6
4
Lashing
7
4.1.1
4.1.2
4.1.3
Lashing for stability of the cargo
Lashing for internal forces
Lashing for local stability of the trailer
7
7
7
Appendix A: Examples of internal forces of transport
8
Appendix B: Example of lashing for unstable cargo
10
Appendix C:Examples of lashing for stability of trailer
11
Status For information only
60000154301
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
1
Date
Region
19 January 2018
Page
3/11 Sap nr.
Europe
Rev.
00
60000154301
Guideline forces on cargo and lashing
This guideline describes the forces generally taken in to consideration for a cargo transported by Mammoet,
to verify if the cargo, lashing and support points are suitable for the planned transport. This document is
meant as a reference for engineers who need to verify cargo to be transported. Readers should have basic
knowledge of hydraulic trailers and their suspensions system. Details of support construction of hydraulic
trailers and the trailer calculations are not discussed in this document.
This document has been originated by Mammoet and is intended to give recommendations and guidelines in
general. In particular cases criteria might need to be increased to cover all dynamic influences in other cases
they could be decreased when influences can be ruled out.
Distinction is made between trailers traveling at different speeds:
• Low speed transport (up to 5 km/h)
• Average speed transport (5 up to 25 km/h)
• High speed transport (25 up to 80 km/h)
Status For information only
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
2
Date
Region
19 January 2018
Page
4/11 Sap nr.
Europe
Rev.
00
60000154301
External forces acting on cargo
External forces are assumed to work parallel to the road
surface. Forces considered are:
• Braking/acceleration in the direction of travel
• Cornering perpendicular to the direction of travel
• Wind, both in line and perpendicular to direction of
travel
The braking, acceleration and cornering forces engage in the
combined center of gravity of the cargos. The magnitude of
the forces depend on the speed of the transport.
Figure 2-1: Longitudinal and transverse forces
2.1
2.1.1
Accelerations
working in the COG of the load
Low speed
For low speed transports Mammoet applies the in house factors based on experience and extensive testing.
Theoretical available braking exceeds the in-house factors. Tests show that at low speeds the transport is
stopped before the full breaking force has been accumulated.
The Mammoet factors in the direction of travel are :
Speed [km/h] Acceleration Application example
0.0-0.5
5%
RoRo operations
0.5-3.0
10%
Site moves
3.0-8.0
15%
Long distance transports
During manoeuvering often the direction of travel changes therefore default transverse acceleration are set
to 5%. Forces perpendicular to the direction of travel are default set to 2% but can be updated when project
specific information is available.
2.1.2
Average speed
For average speed transports Mammoet applies the theoretical available brake/acceleration and curve force.
The factors are fully depending on the type of trailer and envisaged traveling speed.
2.1.3
High speed
For High speed transports Mammoet applies factors from “EN 12195-1: Table 2 - acceleration coefficients
during road transport”. The code dictates
80% Longitudinal acceleration and 50% braking
50% Transverse
Status For information only
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
2.2
Date
Region
19 January 2018
Page
5/11 Sap nr.
Europe
Rev.
00
60000154301
Wind forces
A standard of 1% of the total weight of the cargo is taken into account as wind loads in the Combined COG
For detailed calculation generally a wind pressure of 120N/m2 (Bft 6 at 10 minute mean) is used at the
geometric center of the wind area.
2.3
Inclinations
Figure 2-1 Inclination of the trailer deck will increase forces parallel to the deck and decrees forces perpendicular to the
deck
The inclination of the trailer deck will imply horizontal forces on the cargo and decrease the normal force.
These effects have to be taken into account when checking the lashing and blocking of the transport. Based
on all known inclinations on the transport route.
Status For information only
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
3
Date
Region
19 January 2018
Page
6/11 Sap nr.
Europe
Rev.
00
60000154301
Internal forces within open trailer configuration
In most transports the trailers within the transport are coupled longitudinally and transverse by their internal
couplings. These couplings ensure differences in driving force between drive axles or wrenching of the tire
due to steering differences are kept within the trailer system and are not transferred into the cargo.
However if the internal couplings are not possible, these forces need to travel through the cargo. Mammoet
applies the following in house factors based on experience
• 50% of the theoretical driving force (of the strongest trailer)
• 25% of the cargo supported by the trailer when there is no drive force available within the trailer.
The forces engage at the road level introducing both moment and a force parallel to the road surface in to the
cargo
Figure 3-1: Internal forces within open configuration blue arrows show local forces in the trailer gray arrows
show internal forces of the trailer
Status For information only
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
4
Date
Region
19 January 2018
Page
7/11 Sap nr.
Europe
Rev.
00
60000154301
Lashing
There are several reasons for lashing:
• Stability of the cargo on the trailer
• Internal forces
• Stability of the trailer
4.1.1
Lashing for stability of the cargo
If the tipping base of the cargo is smaller than the tipping base
of the trailer (based on the hydraulic setup), it is possible for
the cargo to tip over before the trailer will tip over. Therefore
the cargo will be lashed to the trailer to avoid tipping. Ensuring
the trailer and cargo act as a single object and the assumption
of the combined cog calculation used is correct.
4.1.2
Lashing for internal forces
Figure 4-1: Lashing to secure load on trailer
The internal forces as described in chapter 3, require a
connection between the trailer and the cargo. Figure 4-2
shows an example of lashing for internal forces. Here the
cargo; a column with saddles is loaded on a trailer with turn
table. As the turn table construction creates a hinge at the
bottom of the saddle, the lashing is installed to keep the
saddle stable and transfer the internal forces from the turn
table to the column. The turn table itself needs to be secured
to the trailer for the complete system to work.
4.1.3
Lashing for local stability of the trailer
Figure 4-2: Lashing for internal forces
The complete trailer set up and hydraulics will generate a
global stability for the full trailer arrangement. This global
stability is verified by our in-house software. Locally all
trailers also need to be stable underneath the cargo.
Generally this stability is provided by the contact area
between the trailer and cargo (as described in the
Mammoet stability guideline). This area should provide
sufficient stabilizing moment to counteract the destabilizing
moment generated by either the internal or external forces.
If this moment is not sufficient, lashing is used to provide
the additional stabilizing moment.
Status For information only
Figure 4-3: Lashing for local stability
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Date
Region
19 January 2018
Page
8/11 Sap nr.
Europe
Rev.
00
Appendix A: Examples of internal forces of transport
In the picture below the connection for internal forces is marked in green
Status For information only
60000154301
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Status For information only
Date
Region
19 January 2018
Page
9/11 Sap nr.
Europe
Rev.
00
60000154301
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Date
Region
19 January 2018
Page
10/11 Sap nr.
Europe
Rev.
00
Appendix B: Example of lashing for unstable cargo
In the picture below the additional lashing is still in the process of being connected to the cargo.
Status For information only
60000154301
BEST PRACTICE
Subject Forces on cargo and lashing during transport
Doc. nr. 020201000
Date
Region
19 January 2018
Page
11/11 Sap nr.
Europe
Rev.
00
Appendix C:Examples of lashing for stability of trailer
In the picture below the additional lashing to provide stability to the trailers is marked in green
Status For information only
60000154301