So we have the following elements; 4 steel rods with holes, 10 (or 11) bricks, and 40 toothpicks. There are total 80 (or 84) glued connections.
70% of the connections must fail, i.e. 56 or so.
Have a try! Purpose is to see if part C can one-way crush down part A. Maybe only one connection (of eight) will fail at first impact, then top brick of part A displaces at one corner, part C will be pushed to that side and maybe a few more connections fail. But not 56!
So to start with, ensure that all eight top connections steel rod/toothpick/brick fails similtaneously. If only four connections fail - 50% - you are off to a bad start.
Maybe with luck, you may break 40 connections in part A, but any time you break one connection there is another with no load acting on it. Difficult to break that one.
I have a feeling a lot of toothpicks will remain attached to rods or bricks after your attempt.
Ok, I think I understand now. You consider the "toothpicks" to be a component, when they are just part of the connection mechanism. Toothpicks are no different than a screw, nail, or rivet, in this scenario. I've used them simply to use a "connection" component of the same order of magnitude strength as is required, instead of something like pure glue which is 1000s of time stronger than is accurate, relative to scale.
The toothpick breaks before the glue because its weaker than the glue. You dodge the issue completely by making the toothpick a "component" instead of a failed connection.
Your goal is "break" the adhesives.. and you are hiding behind the fact that at these scales, adhesives are infinitely stronger than the force that can be generated. In other words, you've changed the game from anything to have anything to do with 9/11 and more it's a game of finding an adhesive that is "just" strong enough to hold something up. This is an easy problem for me to dodge, but let me start with another question.
If I built the structure above, and dropped the top brick, and every single toothpick in the structure shattered... leaving us with
* 4 rods with half-toothpicks stuck out of them...
* 10 bricks with half-toothpicks stuck out of them...
...all strewn out on the floor... You wouldn't consider this a "collapse" of the building valid of winning your challenge? You don't think this demonstrates fairly conclusively that a less than 10% of the mass, dropped from a modest height, can destroy an entire structure? Really?
Second question, here's a simple modification. Instead of toothpicks and glue, I use a tiny bit of clay. It will harden and be extremely brittle, but it will connect the bricks to the steel rods. When I drop the top brick, it will shatter the clay connections and it will progress to the floor, shattering all of the connections. Will this result in a successful experiment? Will this satisify the challenge?
Produce a structure that self-destructs by dropping a piece of it on it.
My structure does this. Despite the fact that my structure is lying on the floor completely and utterly demolished with no "floor" connected to any "column", you say it's not "destroyed". Your definition of "destroyed" needs work, I think.