Secondary Structure / Cold Form Sections

Secondary framing is an important component of many Pre-Engineered Buildings, also referred to as secondary structural, this type of framing runs in between primary framing elements, creating a structure within a structure. This purpose of secondary framing is to distribute loads from the building’s surface to the main framing and the foundation. Secondary framing can add longitudinal support that helps resist wind and earthquakes and it can provide lateral bracing for compression flanges that are part of the primary framing increasing overall frame capacity.

Secondary structural framing consists purlins, girts, eave struts, wind bracing, flange bracing, base angles, clips and other miscellaneous structural parts

Purlins & Girts

Purlins and Girts are structural members made up of cold formed steel Z & C sections that are supported on columns, rafters or building walls. They can be lapped and nested at the supports, to create a continuous beam configuration. They are placed under the roof, wall and the perimeter of the building and serve as supports to the roof sheeting and wall cladding. Purlins, girts and eave struts are cold formed steel members which have a minimum yield strength of 345 MPa (50,000 psi) and will conform to the physical specifications of ASTM 572 (Grade 50) or ASTM A653 (Grade 50) or equivalent.

Eave Strut

Eave Struts are typically constructed from cold formed ‘C’ sections and are rolled to suit the roof slope. Their primary function is to support the gutters and also to act as a junction of the roof and the wall cladding. This member transmits longitudinal wind force on the end walls from roof brace rods to wall brace rods.

Angle / Rod Bracing

This member is designed to ensure the stability of the building against forces in the longitudinal direction due to wind, cranes and earthquakes. It is made of a cable which is forged into a rod terminal and this arrangement is then fixed on a structure using a hill side washer, nut washer and a nut.