I have developed one simple program for calculating moments in rectangular plates. As opposed to circular plates, we do not have exact equations for calculating rectangular plates. There have been a lot of experimental work done that have produced tables with which one can calculate moments in rectangular plates, depending on the boundary conditions (how is each of the 4 sides of the plate supported).
One of this kind of tables were made by Czerny, and which this program uses. User has to input the following:
- uniform load on the plate – q
- shorter dimension of the plate -lx
- longer dimension of the plate – ly
According to the table selected in the top (which takes into account how the plate is supported) the program calculates moments Mx, My, Mxy, Mex and Mey.
When this is done, we can also select the type of concrete and steel, deformation of concrete and steel and thus calculate the minimum depth of the plate. Program also yields coefficients for Kd and Ks, from which we can determine how much steel we need for the plate to be safe (according to EC2).
Why would anyone need to use this program if we have so many computer programs for structural analysis? Well, we sometimes have to check if the results given by a sophisticated program is within values that we predicted. So if we know what the boundary conditions and the load of one plate is we can check what values we get with this program and compare the two results, if they both yield similar results than we can be assured that calculations by structural analysis were done correctly (i.e. everything was properly inputted into the program).