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Load History Parameters and AS 3600

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I would like to have a question about how should apply “Load history parameters and AS3600” as per link below: 

https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/36046/load-history-parameters-and-as-3600 

To clarify I would like to separate some queries following: 

  1. In any case, input creep factor in Ram need to + 1, after obtaining creep factor from Equation 3.1.8.3?
  2. Is the “Initial load application” equal to “concrete maturity” (concrete age)?

            I ask this question because sometime in my country they use additive to push concrete age early mature, and they usually take the propped at 7 days. But at this time because of the additive the concrete age               is reach full compressive strength at 28 days. So the “Initial load application” is 7 days (remove propped), but the concrete age is actually 28 days.So what is the key point in this situation, “the day of apply load” or “the day of concrete age”?

            > So what is the key point in this situation, “the day of apply load” or “the day of concrete age”?

           And what should we use in Ram? For above example: 7 or 28 days?

  1. In the link above, you have an example about creep factor for initial loading at 28 days.

            But the picture show input Ram Concept showed 14 days? Is it correct?

            If it is correct, mean that you have to put it 14 days by default for any case? Or else?

            Below is picture captured in the web:

            

         4. It is said that: “ACI 209 uses a modification factor to account for initial load application times other than 7 days. This factor is automatically determined by the program and should not be                              incorporated into the input creep value.” Mean that if I design with ACI code I need to put 7 days and creep factor corresponding. And If I want to apply load at 28 days ( or 3), I just need to change “Initial                  load application” to 28 (or 3), and leave creep factor as it is?

         5. In the link I see a plot of calibration of k3 factor. But the AS3600 curve (blue line) seem not so corresponding with the one state in AS3600 – 2009 code.

             For example:      

  

7 days

28 days

365 days

Blue line (in web)

~1.45

~1.1

~0.75

AS3600 – 2009

1.75

1.1

0.9

   

        6. I am list here step by step to apply creep factor for Load history in Ram Concept from what I understand so far, please advise if any:

          a. Use the equation 3.1.8.3 in AS3600 to calculate design creep coefficient with k2, k4, k5 as per code. For k3, I take the value from green line above at 7 days which k3~1.45

          b. Use this value and + 1, then put into creep factor in Ram.

          c. Input 7 days in “Initial load application”.

        And if I want to apply load at 28 days ( or 3 days), I just need to change “Initial load application” to 28 (or 3), and leave creep factor in step b above as is.

Thank in advanced,


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