In Staad.Foundation i am having problems getting the sum of the forces to work out for a slab on grade rack analysis. I have a model of a slab with loads input as a Quadrilateral load to spread the load out a bit. When i take the loads from the "calculation sheet" and copy and paste it into excell along with the reactions, i get 2 different results. I have determined that it is specifically related to 4 of my supports (the last 4 in loads in load case 2 - Rack Load). For these 4 columns, the total applied force should be 2.99k, however it appears that only 1.5K is being resisted. Can anyone explain this?
Also, when doing a slab on grade analysis where the bearing area is critical, it would be easier to add a column grid and then use a base plate area. When using the column grid, it did not appear to me that the column area affected the distribution of the column reaction (although admittedly i didn't have a pier). If a pier were added, would the column load be distributed over the pier area?
I've will try to upload my model and an excel file with some results (the upload isn't currently working)
Thanks in advance.
Ryan