Enough history, now to the present.
I will prepare a diagram showing the plan view of the mat in a spread foundation.
For the layperson:
In ACI (American Concrete Institute) terminology, “nominal” refers to the standard or intended size of a rebar, often based on its diameter. For example, #8 rebar has a nominal diameter of 8/8 inches, or 1 inch. Rebar sizes are designated by numbers, with each number representing the nominal diameter in eighths of an inch (e.g., #3 rebar is 3/8 inch diameter).
Typically, two grids of rebar are required: a top grid layer and a bottom grid layer. The bottom grid layer is designed for positive moment, the top grid layer is designed for negative moment. In my macro, I illustrate only one of the two grids. A full engineering spreadsheet would, of course, show both grids.
The foundation is specified by length and width. Rebar is specified by nominal size and maximum spacing. In an engineering drawing the number of rebar is also called out, for clarity.
I do not address the design procedure, only the drawing of the finished design.
Below, I offer a static image illustrating a typical rebar layout drawing. Note that this one is entirely sufficient; it is not to scale and that’s okay, even preferable; its is driven by Excel cell values; it was handmade using Excel; and it is easily modified for each new foundation design.
Here is a short video illustrating use of the macro.
Note that I simplify and shorten the input dialog, using only two prompts.
The first prompt asks for 3 parameters; the user responds with a space delimited entry of ‘Cover Xdim YDim’. The second prompt asks for 4 parameters; the user responds with a space delimited entry of ‘VBar Xspace HBar YSpace’. Obviously the macro parses the input thereby obtaining the parameter values.
Immediately the diagram is drawn and labeled.
# for example Cover, Xdim, Ydim = [float(e) for e in rebarparameters.split()]
