Lifting and Stabilizing: Proper Use of Buttress Systems
Photo: David Pease
David Pease, Carolina Fire/Rescue/EMS Journal
When we look at stabilization we need to consider taking that extra “few” seconds to access our scene and vehicles, and what it will take to properly stabilize the vehicles involved. We talked about some of the basic wood and plastic cribbing as well as the types of movement we are trying to prevent. I want to look at utilizing the “buttress system” in stabilizing vehicles where cribbing would become extensive. When we refer to the buttress system, we are talking about using some type of extended jack or timber that reaches higher on the vehicle and has the bases secured by a series of straps or chains.
Let’s look at some different types of systems and how they work. The most basic of these would be to use 4″×4″ timbers cut to the required length. These could be carried in 12ft lengths and then properly cut at the rescue scene to the appropriate size required. A pre-manufactured base would be the best thing to use in securing the base, as the four by four would fit into the base and straps could be secured to the vehicle. Manufactured ends are also made that can be fitted on the tip for better wedging and friction. This type of system, although relatively inexpensive, takes up a lot of space and requires a fair amount of work on the scene. One advantage of wood cribbing when it comes to potential failure, is wood will pop and creak before failing under a heavy load.
There are several other systems on the market that use perforated tubing, either round or square that allow for easier use and storing. These systems are usually steel or aluminum. They come with either straps attached to the bases or attachment points for you to add a strap. They also have different designed tips to secure to the vehicles. Some of the more versatile systems even have the capability to lift and stabilize. As with wood, steel has the characteristics to show failure before it occurs. Steel and aluminum will show deflection and torsion and bend before failure. This is a plus, since we seldom know exactly what the weights and forces are that we are dealing with. There are also composite systems available, but personally, I do not care for these, and this is why. Composites are relatively light, but to match the strength of steel they must be made relatively heavy , which makes them not so light. They do not take the abuse of “beating and banging” as steel does, nor do well with long exposures to sunlight. However, the thing that scares me the most is, the only indication of failure will be cracks in the composite material that you may not ever notice. If over stressed, the jacks are subject to sudden and catastrophic failure. This is not a good thing. I think for the money, you would be better off with metal.
Remember that using this type of system does not eliminate the use of cribbing and wedges. These should be used in conjunction with the jacks and struts. We are always looking to create as many contact points to the ground a s possible and within reason. Four points of contact is our ideal goal and what we shoot for, but additional points of contact is even better. Utilizing the stabilization jacks does take up less space on your rig, and gives you a much greater capability of stabilizing higher loads. It is the ideal choice for heavy vehicle rescue, as I use them extensively in our heavy vehicle rescue classes. You are dealing with much greater heights and weights in these types of crashes.