You’ll also notice a mid-point brace in the diagram. This brace must be added if the raker is 11 feet or longer. Being that rakers are always built in pairs, horizontal bracing will be used to tie the systems together. Horizontal bracing, like mid-point bracing, is made from 2x6 lumber. Our placement points for horizontal bracing are at the top and bottom of the raker. This bracing will fight the effects of lateral loads. We will also add cross bracing to the system, which is nothing more than creating an “X” on top of the horizontal bracing. This also is made from 2x6 lumber and its job is to resist any torsional loads.
A flying raker (see Figure 4) is utilized when neither the soul plate nor the upright can sit flush on the wall or ground due to rubble. It, like any raker shore, can vary in its degree (45 or 60). The public service announcement for today is that “this is only a temporary shore.”
You’ll notice in Figure 4 that the raker is going into a trough. The trough terminates the load and helps to direct it into the ground and thrust block. If you look between the trust block and the trough, you’ll see a pair of wedges. These wedges will provide an upward force, helping to support the intended load. The design load for a flying raker is approximately 1,000 pounds, which is significantly less than that of a solid soul raker. So you may be saying to yourself, “Why use it if it’s weaker and only temporary?” It’s used as a means to create a safe haven to then construct a solid sole raker or a split sole raker (which we’ll discuss later). Once this system is in place, you can clear any debris that is on the ground and then begin to build permanent systems. The last bit of information I’ll throw out there regarding the flying raker is that, unlike other rakers, this system must be connected or “anchored” to both the wall that it’s supporting and to the ground.
The last raker system we’ll look at is the split sole (see Figure 5). This may look like a solid sole raker at first; however, look at the sole plate, there isn’t one. The 2x6 pieces of lumber are acting as the sole plate here. This is done in the event there is minimal debris on the ground that’s preventing you from running a flush sole plate.
When all is said and done, there is a raker shore to fit most situations. Paratech makes a product called Paratech Long Shores that can be used to build raker systems (see Figure 6). The Deployable Raker Kit comes complete with wall and sole plates. You can leave these systems in place, or use them as a quick way to support the structure or create a safe haven in which you can then build a lumber system inside. It is very versatile and very smart.
There are two aspects of shoring operations that you need do adhere to each and every time you’re faced with this type of operation. The first being rescuer safety. Never enter a collapsed or damaged structure until you’ve taken the necessary steps to provide a safe working environment for yourself. Next, your shoring systems must be built to spec 100% of the time. If there’s one thing you should have taken away from this and the last article, it’s the double-funnel principal. This article touched on shoring systems that transferred loads from point “A” to point “B” in directions other than vertically, such as the raker shore. The bottom line is whether you’re building a simple crib stack or a raker shore system, you need to understand the funnel principal and respect it. Next month we’ll look at a few final shoring systems to wrap things up.
Until then, stay safe and stay progressive.
MICHAEL R. DONAHUE is a 14-year veteran of the fire service assigned to Rescue Company 1 in Elizabeth, NJ. Mike is the owner and founder of Progressive Rescue, a company dedicated to further firefighter's in all aspects of the job. He holds the title of rescue specialist with New Jersey's Urban Search and Rescue Team (NJ-TF1) and he is actively teaching at Middlesex Fire academy and the Middlesex County College as their Fire Science Program Coordinator. Mike has been on two Firehouse.com podcasts: The Buzz on Technical Rescue: Rope Rescue Operations and The Buzz on Technical Rescue: Special Operations Roundtable. He has taught as a HOT instructor at Firehouse Expo and is the Specialized Rescue Forum moderator for Firehouse.com. You can reach Michael by e-mail at firstname.lastname@example.org.