Secondary members act struts that help in resisting part of the longitudinal loads that are applied on the building such as wind and earthquake loads, and they provide lateral bracing to the compression flanges of the main frame members thereby increasing frame capacity.
Secondary framing consists of the elements which support the roof and wall sheeting and which transfer loads to the primary framing:
- Purlins
- Grits
- Eave Struts
- Bracing Systems
Purline & Grits
In pre-engineering Building, mainly purlin & Grit of Z & C shapes of various sizes. Typically cold form member used for the roof are called purlin and for the walls it called as grit however profile for the both in general is the same.Eave Struts
Eve struts shall be Z or C sections with various Depth & Thickness as per requirement at the End of the rafters. This member transmits longitudinal wind force on the end walls from roof brace rods to wall brace rods. Such Eave Struts are constructed from the cold formed C-Sections. Eave Struts are located along the sidewalls, at the intersection of planes of roof and side walls.