Dear Adarsh M.s ,

The  data about the value of friction coefficient you may find in Raous M., Karray M.A. Model coupling friction and adhesion for steel concrete interfaces // Int. J. of Computer Applications inTechnology 2009 Vol. 34 # 1, P. 42-51 as well as useful  information about methodical aspects of such tests (attached). 

Best regards

Dear Colleague, because of friction in the contact of ribbed bar and concrete matrix is summarized by strong mechanical engagement and adhesion of surfaces,  you may estimate the friction (tangential)  stress as sum of 1) shear cogesive strength of concrete and 2) adhesion strength between steel and concrete by shear as well.

Then the friction coefficient (which you need) will be formally calculated as a ratio of tangential and normal (compressive) stresses. But the normal stress is not easy determined in this case.  To my mind,  the numerical modelling  in terms of tangential stress is better than in terms of friction coefficient.  

All the best, Serge Shil'ko

Dear Sergo, could you please be more specific? I Didn't get your points.

Cordially Behzad

Dear Behzad, try to use the  friction coefficient equal 3 or even more  for the rough "frictional" simulation of enough strong joint in contact of ribbed bar and concrete.  

Sincerely yours, Serge

Thanks sir for your reply.

but i have one another question from you!

what type of interaction I had to select from the list?

because of being beam(truss) section of rebars, the software doesn't accept the surface-to-surface contact type, once I want to choose rebars as a master surface !

probably  friction coefficient of Concrete to Steel is 0.45

Yes, this value of friction coefficient (near 0,45) is true for smooth contacting surfaces of steel bar and concrete.

thanks Dear Reza and Dear Shil'ko. I am working on abaqus just for weeks and I'm not so familiar with Interaction laws. I don't know what should I do?

to define slip bond between ribbed rebar and concrete, which one is the master or slave surface?    what type of interaction, should I select? what friction formulation should I use for concrete and ribbed rebars?

Thanks a lot for your help.

you can consider the concrete-bar interaction using "embedded region" provided in "Constraint" section. It is not needed to define the contact between the steel bars and concrete using "Normal or Tangential behavior" . You can define such interaction when you are defining the rebars as 3D solid element and not for truss element. 

In ur case I prefer to use  "embedded region".

But If you are interested to define friction 

1- U can select "surface to surface" then select the outer surface of bar as master surface and inner surface of the concrete as slave .

2- Pressure-overclose- hard cocntact

3- just put 0.45 in box of Coeff

Dear researchers,  

Can anyone provide me with a reference in any published article for this value of coefficient of friction between concrete and steel =0.45.  

Thank you

Dear Adarsh M.s ,

The  data about the value of friction coefficient you may find in Raous M., Karray M.A. Model coupling friction and adhesion for steel concrete interfaces // Int. J. of Computer Applications inTechnology 2009 Vol. 34 # 1, P. 42-51 as well as useful  information about methodical aspects of such tests (attached). 

Best regards

Dear Shil'ko,

Thank you.