Strain Values of con_ma and con_frp material types

[MOUMTZIS IOANNIS]

Hello,

I' m trying to change the strain values of the above material types, by editing the material properties (through sample plot strain columns). Even though I managed to change the values with the ones I wanted and the stress-strain graph get the desired form, when I press ok and stop editing the material, all the changes I made in the strain columns are lost! Why is that happening? Is there a possibility to save the strain-stress graph with the strain values I want?

Best Regards.

[Stelios_Antoniou]

If you mean the strain values in the table of materials module, they are used just for display purposes, so that the user understands the hysteretic rules of the model.
Hence, contrary to the material properties which are stored to be used in the analysis, these strain values are not saved (the strain time-history is not a material property)

[MOUMTZIS IOANNIS]

Êýñéå Áíôùíßïõ,

¸÷ù êÜíåé êÜðïéá ðåéñÜìáôá áðü ôá ïðïßá Ý÷ù ðÜñåé êÜðïéåò êáìðýëåò ôéò ïðïßåò êáé èÝëù íá åéóÜãù óôï ðñüãñáììá. Ãßíåôáé ìå êÜðïéï ôñüðï íá åéóá÷èïýí ïé óõãêåêñéìÝíåò êáìðýëåò óôï Seismostruct?

Ôï ìüíï ðïõ ðñïóðÜèçóá åßíáé íá áëëÜæù ôá Materials Properties ìÝ÷ñé íá ðåôý÷ù ôçí êáìðýëç ðïõ èÝëù, êÜðïéåò öïñÝò ôï êáôÜöåñá áëëÜ óå êÜðïéåò Üëëåò ðåñéðôþóåéò äåí Þôáí äõíáôüí íá ãßíåé!
¸÷åôå íá ðñïôåßíåôáé êÜôé?

Åõ÷áñéóôþ åê ôùí ðñïôÝñùí.

[Stelios_Antoniou]

First and most importantly, the Forum's official language is English, hence do use the English language for all the messages that you post, so that all users are able to read them!

Secondly, you cannot duplicate experimental results of RC members using the con_ma and con_frp hysteretic rules, which is what I pressume that you are trying to do. And anyway there is no point in that.

What you should do is to model the structural configuration of your experiment and compare the experimental results with the hysteretic curves in SeismoStruct's post processor

[zsaeed]

When we use con_frp as cover of con_ma for simulating effect of CFRP wrapping on concrete,i want to know that do we need to modify the confinement factor for con_mat as it is now confined by Spiral reinforcement and CFRP wrap as well Or con_frp will induce its effect automatically and we just put confinement factor for Con_ma just for spiral reinforcement ??

I explain my query further ..My column has CFRP wrapped on half length of column due to which for bottom portion i used con_frp (cover) and con_ma (core concrete). whereas for top column i provided con_mat (cover with confinement factor of 1) and con_ma (core concrete with confinement factor of 1.6835)

soo i want to know that for lower portion for con_ma do i need to increase the confinement factor beyond 1.6835 (in order to account the CFRP confining ) or let it be the same assuming that con_frp will induce its effect automatically ??


Thanks

[fakharifar.mostafa]

con_frp or any other confined concrete constitutive model in SStruct or other similar packages affect their corresponding fibers they're assigned to. Your confining pressure from the existing spirals is already high enough.

By high I mean, I don not think that would matter that much at this level of confining pressure from your existing spirals, to apply the con_frp to your cover or to your core concrete. Remember, in addition to crushing of confined concrete, fracture/buckling of longitudinal reinforcement and instability due to P-delta are also sources of structural failure.

To have a clear understanding of above statement:

Make a circular cantilever column and do the below parametric study on your column cross section under lateral pushover analysis:

1- con_ma (1.6835) to core + con_ma (1.0) to cover

2- con_ma (1.685) to core + con_frp (with a very high FRP jacket ratio) to cover

You'll see that you results won't deviate that much. 1.685 is a value for a well-confined cross section. In simple words, there is a threshold for the extent of improvement upon introducing FRP jacketing.

For further insight, repeat the above parametric study under very low and very high axial load. You'll see the effect of your confining pressure will pleateau on the lateral force-dispalacement curve.

Hope this helps you furthering your model.