hello everyone
my question is when i am assigning & treating the element as tension only member command to beams , i am having some problem in my model while designing. you can see it while clicking the perticular beams assign as tension only members. please check the inverted "v" in the model. thank you.
ryanasu,
You wrote :
I just wanted to clarify something. I'm using tension only members. So to my understanding, during a single load case/combo, staad will iterate and inactivate tension only members that are carrying any compression load. In the next load case, the members that were inactivated will remain inactive unless the change command is used. So I am not changing any structural conditions, but staad is automatically doing it. Unless I analyze the file and determine which load cases required iterations, it seems as though for tension only members I should have perform analysis under every load case. Does this seem correct to you?
Answer :
Before the start of the analysis for any given load case, the full structure is restored by the program, meaning, all members with the tension-only attribute are considered active in the model. Hence, the state of the structure at the end of the analysis for that load case (in which some of those members may be switched off) is not used as the starting condition for the next case.
In other words, this is like the program inserting the ANALYSIS and CHANGE command on its own between successive load cases. After any load case is solved, it "resets" the model to the full state automatically before it starts to solve the next case.
To summarize, you have to enter ANALYSIS and CHANGE only after the last of those cases, not for each individual case.
Kris -
I'm reading two different recommendations from you. In your first paragraph, you agreed that ANALYSIS AND CHANGE should occur at each load case/load combination. In your last paragraph, you say that staad automatically re-activates all members prior to the ANALYSIS command. To me, this means that I don't need the change command. Please confirm. Thanks
You wrote ;
To me, this means that I don't need the change command. Please confirm.
Answer:
Correct