coefficient of friction: concrete on concrete 1

[shaqattaq]

what is a representative coefficient of sliding friction for concrete on concrete or concrete on mud-mat?

 

[ishvaaag]

Concrete on soil look for table 5.5.5 B in AASHTO standard.

In any case common assumption/specification for cohesionless soil is not to take more than 2/3 of angle of internal friciton of soil at base.

For concrete on concrete it depends on surface status. You can use as guide the values recommended for shear-friction. If plain, coef friction 1 and if rough 1.4, Nilson (old) gives.

Concrete on steel, 0.7, Nilson gave.

I have seen some other values for shear friction in code setup.

 

[bldgdr]

I think the 0.7 number is for concrete placed against steel. I have seen numbers of 0.45 for hardened concrete against steel such as will precast panels supported on steel beams. Has anyone seen other numbers?

 

[bldgdr]

Some further information. PCI uses a coeficient of friction of 0.4 for concrete to steel. That is for hardened concrete placed on steel. See table 6.6.1 in the PCI design handbook.

 

[dbuzz]

The coefficient of friction for concrete on rock is often quoted as 0.30 to 0.4.

See Thread592-11538 for simlar query and responses.

 

[PEStructural]

See ACI 318 Section 11.7.4.3. It clearly calculates the coefficient of friction of concrete to concrete in different scenarios.