Sunday, December 6, 2009

Mysteries Of The Pyramids Revealed

While visiting the folks a while back, I stopped by to visit some friends and came across a cribbing and shoring class being given at their department. A beautiful day with decent light forced me to take some photos. I have attended a small portion of this class, it was well worth the time spent on it.

The objective - Move a one ton concrete block 25 feet to a 30 inch high obstacle. Lift the  block over the obstacle and across a 25 foot gap, then lower the block back to the ground. All of this using hand tools, a rope, cribbing, some pipe and a few timbers. Maybe aliens didn't build the pyramids after all and this is how the Egyptians did it.

 In this picture, the block has already been lifted onto the pipes and has been rolled to a ramp which has been constructed to go up the obstacle. Large pry bars are used to gain a purchase point under one side of the block. Three, four pry bars - whatever it takes. Wooden wedges are placed under the narrow space created by the pry bars and the process is repeated until the block is high enough to place pipes under the block. Once the block is up on the pipes, it can be rolled used the pry bars as levers to push it along.

The block is arriving at the ramp. Once the pipes roll out from the block, they are repositioned to the front of the block and the block then rolls over it. In this image, the have already attached the rope to the block. It will be used to pull the block up the ramp The two pry bars visible to the rear of the block were the ones used to lift and then propel the block.

The block starts it's journey up the ramp, there is tension on the rope. The pipe has just been repositioned to the front of the block, one is probably just getting ready to pop out form the rear.


Ready pull! Pulleys are used to create a mechanical advantage, yet it still takes a few guys to pull that block up the ramp. Each person grabs onto the haul line and walks/pulls to the rear. When the last person runs out of room, he lets go of the line and goes to the front. This is repeated until the objective is obtained.

 Partway there. The block has been lifted and is ready to be pulled across the gap. A bridge is created using timbers. Note the cribbing structure created on the left side of the photo. These evolutions use up a lot of people and wood. A lot of time is used as well. I didn't get to photograph the lowering of the block, I ran out of time.

Another portion of this class covers the shoring of unstable structures. Once a structure is assessed for hazrds and the shoring needs have been determined, a system is developed to construct the required shoring.

Since you are usually dealing with dangerous work areas and restricted space, much of the shoring system is constructed outside the structure and then assembled inside. The team inside has already determined their needs, measured the size and quantity needed and has relayed the information outside. These people are building this to the interior teams specs.

Once the components are assembled, they are brought inside and assembled. Here, the shoring is designed to support a weakened ceiling. Shoring, although simple in design, is an art form. You better know what you are doing.

I wish I had more time to take even more images. There was a lot of stuff going on that day. Thanks to BillyBob for letting me photograph his beloved drill grounds.

Thanks for reading,


  1. Moving those blocks of concrete is a pain! We trained a bunch of folks to do that and some other tasks earlier this year. By far, the most interesting thing was folding a car in half using chains and a hydraulic ram.

  2. Dear Captain Schmoe,
    I thought a bunch of people would have written on this one. I am fascinated to learn (although I should not be, I guess, b/c it only makes sense) that everything would be measured first and then pre-cut before being "shored" for safety's sake. I am sure it is a huge engineering feat, too. For floor weight capacity, etc. The positioning of it.

    I have a couple of questions, though. I feel ignorant in having to ask, but here's my opportunity, right?

    I assume the shoring is to assist when the fire department is investigating for arson, or excavating for rescue operations/body recovery after a fire?? And the blocking. I don't know what it is for.

    Please excuse my ignorance.

    Ann T.

  3. Well Ann,
    I know that some of the people that were attending this class were members of a regional USAR (Urban Search and Rescue Team). They are considered a heavy rescue team, which means they get involved with building collapses among other things. The collapse can be a result of an explosion, fire, earthquake, poor construction or demolition techniques or even something else. Some of the USAR teams have structural engineers that are assigned to the team to do structure assessments, weight assessments etc.

    A friend of mine was a FEMA USAR team member. He went to the Murrah building bombing in OKC. They did a lot of this shoring to stabilize the portion of the building that was damaged but still standing.

    The block exercise is used to teach students that simple machines/tools can do a lot of work. It also teaches teamwork, safety, cribbing techniques etc. You can get a lot done with levers, inclined planes and pulleys.

    There were some people in this class from places I never heard of. I think they were there as part of their agency's technical rescue team. From what I saw, most of the folks there had never worked with each other. Yet they got the exercises done, at least the ones I saw.

    Thanks for reading.

  4. Dear Captain,
    Okay, thank you! That's what I thought about the shoring, and the block. Appreciate you checking back and answering poor ole Ann's Dumb Questions.

    Ann T.