huangyhg

concrete friction coefficients
does anyone happen to know what the static coefficient of friction for concrete on concrete is? approximately?
rufus182,
i have not heard about the static coefficient of friction between concrete to concrete. but know the friction coefficient bet. rubber and concrete which is 1.0.
extending the same logic and since the concrete is heavy the static coefficient of friction may be around 1.0.
visit following web page.
i would say 0.6, per aci 318-95 section 11.7.4.3.
yeah... i agree with daveatkins, but the friction coefficient is 1.0 for roughend concrete.
based on the advice given in british standard bs 5975, the coefficient of friction are given as lower bound values:
concrete/concrete = 0.4
concrete/plain steel = 0.1
concrete/softwood = 0.4
concrete/hardwood = 0.3
concrete/granular soil = 0.4
andy machon


its very difficult to give even an approximate answer. it will have a bearing on the condition of two concrete blocks. it will be significantly different in both of the following conditions:-
1. between smooth concrete blocks (seperately cast)- 0.3 to 0.4
2. single casting of concrete block cracked into two parts 0.5 to 1.0.
moreover present of moisture and presence of crushed material between the surfaces may bring down the friction factor dramatically. you have to be more specific about the conditions and then you can arrive at a more reasonable approximation.
thanks for the good advice & tips dudes. we are down a tunnel at the moment so yes, moisture is a condition. the bits were cast separately. we'll go for the side of caution: 0.3 will do for now.
watch your six
rufus182
flamby (or anyone else),
any chance you can point to a reference for the use of 0.3 to 0.4 for seperately cast concrete? we're trying to verify that concrete traffic barriers can be used as ancorage points against a lateral load.
thanks,
jack
several years ago the pca advised me, via email, that i should use 0.4 as cof between a precast concrete building and a cast in place foundation.
ginger,
concrete/plain steel = 0.1 is too small. that is the friction of coefficient between teflon to teflon. we use 0.5 betw steel and conc.
steel on wet oily concrete? 0.1 is not conservative
cheers
greg locock

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