When discussing structural units and its systems, the best way to describes its relationship is, they’re the same but different. This statement works best with structural systems since every layout requires a similar foundation pattern, but each system has different qualities and capacities. There are typically three materials used. Weather its timber, steel, and/or reinforced concrete, each system is able to withstand tension, buckling and wind and seismic forces. From my understanding from reading about structural units and systems, as long as a structure has three sides maintained and stabilized supports, a structure can last for many years. Floors are expected to contain elasticity, while remaining stiff. No matter what material a floor is composed of, it should resist the urge to buckle and collapse. This also depends on the structural systems beneath it. From this reading, I’ve learned that structural systems is closely similar to a domino effect. Since one element greatly depends on the next, and the next and so on. If a systems elements are off, or not capable of withstanding the forces, tension, etc, it will then fail as a structure, which no architect wants!