they want at least another damge indicator besides a home before justifying the highest rating.
Shane,
It seems reasonable that they would need numerous indicators for any EF rating, since in seemingly equal houses/buildings, not all things are equal. In your cinder block building, for example, there can be huge variations in the strength of the mortar within the same building due to something as simple as the amount of water used in the mortar. How much cinder block area is exposed to the wind load? How much interior support is behind that exposed area? Are the blocks in a stacked bond or a running bond (one is a stronger bond than the other)? Was there reinforced concrete in the voids? Was the guy at the cinder block plant trying to remember how many beers he actually drank the night before while he's monitoring the ratio of ingredients that make the blocks? Did the masons meet code in the number of brick ties used in each course of blocks? What was the ambient temperature when the blocks were laid? All of those considerations and many more will have varying degrees of effect on the final strength of the building.
One simple design change led to the deaths of
114 people at the Kansas City Hyatt in 1981. That's why stuff is over-engineered to the point of being ridiculous to the layman - when people's lives depend on it, you have to account for multiple human foibles along the process.
Like in any complex construct, if you really stop to think about the number of variables that have to be in place to make the thing work/be safe, you'll go quite mad very quickly.
If you really want to scare yourself, ponder for a moment the number of people that all had to be sane, sober, knowledgeable, competent and conscientious in the manufacture and delivery of your car, from the time the engineer put ink to paper to the time the salesman handed you the keys, including all of the thousands of small parts manufacturers.
Are homes and buildings that are built on cinderblocks usually have a weaker foundation than those built on a slab foundation or those with a basement.
A lot of basement construction uses cinder block as the basement walls, which then rise up some distance over the ground level. For basements using concrete, the fact that it is reinforced with steel rebar gives it a higher tensile strength than cinder block. Further, it is hard to get a good read on the compression strength of a block, because you cant apply a uniform load on a hollow block.
Short answer: there are far too many variables to make a blanket statement as to whether concrete slab or cinder block foundations are stronger. Sometimes one, sometimes the other depending on variables and the particular application.
