Ram Concept adding program reinforcement

Firstly i saw that someone else has asked a similar question but i was unable to grasp how to fix this problem from their answer.

The pictures below show the design strips in my model along with pictures of the top and bottom program reinforcement. After changing all the program reinforcement to user and running another load history deflection calc Ram Concept put more program reinforcement in (a lot actually and like 20mm spacing).

From the answer to the similar question i saw and the manual, this could be because.

  1. Bars are added to satisfy ACI 10.6.4, which in RAM Concept is based on a cracked section analysis using all reinforcement in the section (both top and bottom)
  2. section 58.6.5 of the manual says something about bars being added to satisfy equilibrium of the cracked section

The thing i don't understand is that when ram concept gives you its first lot of program reinforcement hasn't it already satisfied ACI 10.6.4. Why would simply changing the bars from program to user mean that the equilibrium of the cracked section it suddenly not balanced.

Any information regarding this matter would be greatly appreciated.

Parents Reply
  • Firstly thank you for taking the time to answer my questions, it is most appreciated.

    I am still a little confused though. When i run a load history calc, with no reinforcement ram concept provide me with a fairly reasonable layout of reinforcement. Is it the case that this original layout provided by Ram does not comply with the span detailing requirements.

    If this is the case, when i then change this program reinforcement to user ram then performs the span detailing adjustments which then lead to additional reinforcement that affects the ductility requirements.
Children
  • The initial run with program reinforcement does comply with the span detailing rules. The program bars have been extended to the percentages of the span required by code.

    The problem occurs because the bars are extended during a post-process phase. During this process, bars are extended into cross sections along the span length to satisfy the detailing rules. However, the ductility check is not considering the extended bars when designing those cross sections. When the bars are converted to user bars, the program now recognizes all user reinforcement that intersects the cross section, including the bar extensions from span detailing. The additional reinforcement causes the section to be over reinforced, and ductility problems occur.

    Please let us know if you have any other questions.



  • So is this problem on the development list to be fixed?