By Jake McQueen, Product Manager for HESCO Bastion Concertainer®., HESCO Bastion Concertainer®
SubscribeThe primary advantage of HESCO Bastion Concertainer® over other force protection systems is its ability to utilise locally available fill material to rapidly construct defence walls with minimal manpower and resources.
It is possible to design and construct walls that give complete protection from small arms, cannon, RPG, mortars and shrapnel and fragmentation from larger types of shells or bombs. It is not possible to build a structure to totally protect against the effects of blast from larger explosive devices.
However, the construction of a competent defence wall may substantially reduce the blast effects. One of the main aims in constructing defence walls must be to put distance between the target and the potential site of charge initiation.
HESCO Concertainer® structures provide protection against the effects of weapons by enhancing the mass and characteristics of the fill material. Field guides to force protection normally provide guidance for the design of structures in terms of the thickness of various materials required against defined threats. This will generally suffice for operational structures.
For many applications a single course of the appropriate size of HESCO Concertainer® is the most effective solution in providing a protective structure. For higher walls, stacking of units is generally the solution. As a general guideline, walls should never be higher than twice the base width. For higher walls, stacking units in a pyramid is the answer in achieving greater heights.
In order to achieve a given height, a wide variety of stacking configurations are possible, particularly as the heights increase. Experience has led to a number of configurations that have been proven through use, as well as some guidelines as to configurations that should be avoided. This article will provide a number of proven configurations as well as guidelines for the design of larger walls. For very large or complex structures, competent engineer advice should be sought.
Whilst it is theoretically possible to build structures of virtually any height, experience has led to the conclusion that, walls of greater than 16 feet require special care in their design, and specialised equipment, which may not be readily available.
Design Procedure
The basic design parameters required in the design of a wall are; the threat expected, fill material available, and the target to be protected. It may also be the case that the HESCO Concertainer® is already in theatre and you are consequently limited to certain types and sizes.
Threat Expected
This will be a key determinant in establishing the minimum thickness and/or height required for the wall.
Further information can be found in the HESCO Construction Guide for Engineers, available at the www.hescobastion.com
Fill Material
The fill material available will influence the minimum thickness required of the wall. There are two approaches; first by using available fill. This is the usual method for field survivability structures. In this case, lower quality fill may require increasing the minimum thickness required in the design.
Second, for structures with a longer required service life or where site constraints may preclude thickening the wall, fill may have to be selected or engineered for the particular structure. For the most effective fill, a sand gravel mix with little or no fine material may have to be acquired. As this ideal material does not normally occur naturally, it may have to be created using crushed and screened material.
Target To Be Protected
The target will dictate the plan of the structure and the required height. In some cases, such as aircraft revetment, the designs may also be dictated by the overall layout of the targets. These considerations are dealt with in a number of military publications. In the simplest terms, for ballistic protection, the wall must extend to interrupt the line-of-site from the firing position of the potential attacker to all areas of the target.
For blast protection, the wall must be sufficiently high and long, and separated from the target to deflect the blast wave over and around it, whilst also protecting against penetration from fragments and shrapnel. It is generally accepted that a blast wall should be as high as possible but a minimum of 3 metres.
It is also recommended to have 10’ (3m) space between the wall and the target. This allows for movement of the wall and reduces the risk of the wall toppling onto the target if subjected to overwhelmingly excessive attack loadings.
Conclusion
HESCO Bastion Concertainer® can provide proven protection from small arms and fragmentation, and also provide mitigation from blast.
The design of HESCO Concertainer® structures is a relatively straightforward process which takes into account perceived threat, fill material available and the target to be protected.
Further information can be found at www.hescobastion.com and in the aforementioned Construction Guide for Engineers.
