Bearing Design

For both the both supporting member and the supports, SIzer determines the factored allowable stress perpendicular to the grain F_c^', as described in NDS 3.10 - Design for Bearing , and compares it to the compressive stress at the support f_c^ = R / A, where R is the reaction force at the support and A is the bearing area, i.e. the area of contact between the support and the member.

This bearing equation with F_c^' set to be equal to f_c^ is used to establish a minimum required bearing length to determine the design span, and to determine the design bearing length when you set the input bearing length to unknown.

If a bearing length is established, the design ratio f_c^ / F_c^' is shown in the Bearing and Reactions table of the Design Check output for each support.

For I-joists, only the supporting member is checked for bearing design, Sizer does not design for I-joist bearing resistance.