Friction coefficient for bearings

[bgarbasz]

I am analyzing the stability of an existing abutment for a bridge built in the 1930's and need to determine a coefficient of friction value for the existing expansion bearings. From the original design drawings it appears that the expansion bearings are comprised of a steel sole plate that bears directly on the masonry plate (steel on steel). No mention is made of lubrication of the surface or any other material between the steel plates. I do not believe that the typical dry friction value for steel on steel (0.74) is appropriate for this situation. Does anyone have any thoughts/recommendations? Thanks.

 

[shin25]

The value of the coeff. of friction that you have mentioned sounds right for static condition, but, if the system really moves (which it should) then you have to consider the dynamic coeff of friction well. I do not know what exactly you are trying to figure out, but, dynamic coeff of friction is much smaller than static coeff of friction.

 

[bgarbasz]

I am analyzing the sliding stability of the existing abutment for the reconstruction of the roadway pavement box in front of the abutment. The client requires that we verify that the sliding stability of the abutment is not compromised during construction and I was attempting to determine the lateral force that the expansion bearing imposes on the abutment.

 

[LittleWheels]

Static friction should be the limiting factor, any reason to believe otherwise?
The bearing, if it isn't locked up, will move in a series of jerks as stresses build up (temperature changes, etc0) and are released.