Bearing Length on a Wood Plate

Required bearing length and actual compression-perpendicular-to-grain stress for a point load on a wood plate.

Run the calculator

Example

You enter

Reaction load (lb) 4000
Member bearing width (in) 3
Allowable Fc-perp (psi) 625
Bearing-area factor Cb 1

You get

Required bearing length 2.133
Req area (in²) 6.4

Details, formula, and sources

With a pass/fail against the allowable Fc-perp.

A_req = P / (Fc_perp * Cb); required bearing length = A_req / width; actual f_c_perp = P / (width * provided_length).

Per the National Design Specification (NDS) for Wood Construction - compression perpendicular to grain and the bearing-area factor Cb, by name; Fc-perp values user-supplied.

AWC publishes the NDS free read-only at awc.org; the IBC-adopted edition governs.

Estimate. AHJ and licensed professional govern.

Field names used by the API: load_lb, width_in, fc_perp_psi, cb, req_length_in, req_area_in2

Fc-perp allowable compression perpendicular to grain, user-supplied by species/gradeNDS supplement