Allowable bearing stress

Type of contact

Pin and load-point stiffener contact surfaces, and finished surfaces generally

Sliding or roller bearing

Plate in a bolted joint

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Input

F value

F

Compressive force

P

Contact area

A_p

Bearing stress

\sigma_p

Long-term allowable stress

f_p

Short-term allowable stress

{}_sf_p

Bearing stress check

Notes

Based on the AIJ Standard for Allowable Stress Design of Steel Structures (2019): 5.1(5) "Allowable bearing stress", Eqs. (5.19) to (5.22), and 5.2(2) "Allowable bearing stress of plates in bolted joints", Eq. (5.23).
Where the two materials in contact differ, take the smaller $F$ .
For a pin connection the contact area is taken as $A_p = t\,d$ ( $t$ : thickness of the plate at the pin, $d$ : pin diameter). Otherwise it is the contact area itself.
For sliding and roller bearings, $b$ is the width of the bearing and $r$ its radius of curvature. The contact runs along a line, so the equation takes a different form from the other two.
For plates in a bolted joint, use the projected area: bolt shank diameter times plate thickness. For a countersunk bolt, enter the thickness less half the depth of the countersink as the plate thickness.
No bearing stress check is needed for high-strength bolted friction joints (Standard, 5.2(2)).
The short-term allowable stress is 50 % above the long-term value (Standard, 5.6). The check shown here is against the long-term value.
Where the Standard writes "stress intensity", this page writes simply "stress".