ABSTRACT
Roof and floor plank systems of "assembled concrete blocks" were developed in the 1950s in the United States. The prefabricated planks appear as though built vertically as a masonry wall that was then laid flat. However, they were actually built flat and lifted into place. These systems became generically known as Dox Planks which was the name of one of the systems of the time that has subsequently been discontinued. The planks were mildly reinforced and could be either left untopped or topped with concrete for composite action, as needed. They were intended for use in commercial and residential buildings. The manufacturing of Dox planks was discontinued after precast concrete planks took over the market in the late 1960s. To construct a plank, a row of blocks was first assembled on a work table with the channels up. The units were laid dry with no mortar between the units. They were placed flat or cambered based upon the design.
