Steel beams, trusses and reinforced concrete beams may be used. The same may be said for reinforced concrete structures. The A basic two story office building can be made of wood and as such have a floor that is made of wooden panels resting on wooden beams. The building could also be made of masonry brick or steel framing. In both these cases the preferred floor structure wood be concrete slabs.
Concrete slabs can effectively span spaces and carry loads without deforming.
They can do this with a very thin thickness, especially if the concrete slabs are reinforced with some type of reed bar. As polymers become more and more prevalent in toady's consecution world, polymer based reinforcement is also becoming a viable option. As discussed earlier, there are three main types of structures that could be built for this purpose depending on the material chosen. Wooden frames are cheap and easy to construct, however they are impractical for an building over 3 floor high. Structures of masonry bricks can be built out of clay brick, however the preferred masonry element for fast cheap construction is precast concrete masonry.