There are eight embedded steel plates on the floor of Level 3 which set the placement of all the structural steel above. Each weighs 400 pounds and is made of 1-1/4” steel plate. When the surveyor took the location of each plate they were accurate to within thousandths of an inch. Here is a photo of the top of one of these plates.
Three foot lengths of rebar have been welded to the bottom side of the steel plate. This assembly is tied to the boundary element which surrounds it. The concrete wall below the level of these plates was poured first, leaving 9” from the top of concrete to top of steel plate. A second pour was then made to embed these plates within the concrete slab. These plates were then used as the reference point for theplacement of the structural steel above. The location of each plate defined the location and placement of the structural members. Given the extra-high demand for accuracy in this project, these small plates played a big role.