I have a building with a collection of reinforced concrete shear walls that I am doing preliminary designs for. Some walls are standalone and others are built around cores, so they form C shapes and rectangles. I have grouped connecting walls together to form individual cores, where applicable.
I have assigned base reinforcement to all the walls based on code minimum reinforcement ratios for 12" walls (all walls are the same thickness). When I run the analysis, RAM is saying that some walls do not have adequate reinforcement to satisfy the minimums, despite them all having the same reinforcement and same unit areas. Am I missing something, or is RAM screwing up the area calculation for grouped walls somehow? Am I using the group function incorrectly? I have pasted some examples below. You can see for an individual 12" wall the calculated ratio is what you would get via a hand calc for #4@12"oc. However for the box shape the reinforcement ratio is much lower, and "failing", and I can't figure out where that number is coming from. I would expect these two calculations to match...right?
Any advice is appreciated.
There is a known issue that just came to our attention last week for some closed box type wall group shapes where the program calculated reinforcement ratio is off. In the prior case it was more obviously an issue because the reported ratio was a negative percentage. If you have double checked the reinforcement by hand, then it's best to ignore the warning. Simplifying the wall design groups is another work around. Reference defect 1082277.