Pre-Engineered Steel Structures and Cold-Formed Steel Elements
The primary frame intervals of pre-engineered steel buildings are strengthened by auxiliary structural framing elements. For any main steel structure, these are known as secondary structurals and they can behave as flange bracing for the main structure system. They supplement the transfer of loading to the main frame and provide a key support role for the structure’s roof and walls. Purlins, or secondary roof members, help to structure the diaphragm of the steel roof. Girts, or secondary wall members, play an essential role in strengthening the walls of the building. Eave girts, eave struts, or eave purlins carry out the functions of both girts and purlins – the wall siding is supported by the webs and the roofing panels by the top flange.
Effective Purlin Bracing in Pre-Engineered Steel Buildings
In the design of pre-engineered steel building systems, effectual purlin bracing requires substantial anchorage of the building eave and ridge ends. A conventional assembly technique of sag angle and/or strapping with basic parallel lines will not categorically prevent buckling and failure.