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steel to mortar friction coefficient

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yutang

Structural
May 20, 2002
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I need to know the friction coefficient for steel to mortar and steel to concrete.

I thank you for your help.
 
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Hi Yutang,

the only coefficients coming near to that You are asking for are according to "Hütte" 16. edition of 1896 section I page 206:

stones and gravel to iron 0.42-0.49
masonry to concrete 0.76

I´m not sure that I found the right translation for that from German language.

The coefficient You are looking for may be between these two.

Andreas Nehme
 
The answer for the coeficient of limiting friction between the materials listed is given in table 19 of BS 5975. I don't have a copy with me at this moment.

Regards

Andy Machon


 
Values you will find in a book will be general, but may be close. You will want to look for a value for your specific condition though. Will the mortar or concrete be wet (that is, uncured not surface wet) when the steel is placed against it? If so, the initial, one time only, static coefficient of friction will be higher than once the bond is broken. Also make sure you are getting the static or dynamic coefficient of friction to fit the condition you are concerned with. Again, if you can find these values, they will be only general ranges. the specific steel and mortar or concrete can make a big difference.

From alot of experience, I can tell you that I've seen the values for static coefficient of friction of the same piece of neolite, resurfaced identically, to various ceramic tiles range from .35 to .9 using the exact same testing procedure, ASTM C 1028.

You might do a web search using "mortar, steel, coefficient, friction," and then narrow it down with ASTM 1028 if needed.

Good luck,

Jim
 
Andy Machon above said look at BS 5975 Table 19. (BS for design of falsework) I've just done that and it gives a minimum value of mu for steel on concrete of 0.1
In the past, I have used a value of 0.5 for concrete floor planks restraining the compression flange of steel beams, on the understanding that it is really more like 1.0 in practice, and this has been accepted by checking authorities. In reality it is probably quite variable, and the value you use will depend on why you need to know it!
Good luck.
Richard
 
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