Secondary Framing System
Secondary Structural Members include roof purlins, wall girts, eave struts, C / Z Sections, flange braces, gable angles and base angles. Purlins, Girts, Eave Struts and C‐Sections (used as base channels and as door jambs & headers in framed openings of double sliding doors) are rolled formed from 345 mm wide galvanized coils in thickness of 1.5, 1.75, 2, 2.25 and 2.5 mm.
Generally, in the PEB industry the sidewall girts is connected to the sidewall rigid frame columns and to the end wall columns in a by‐pass manner because it allows cables, pipes, etc. to be laid within the 200mm girt line all around the building. It also allows for a better construction of partial height blockwalls (normally 2.25 to 3.00m high).
Z & C Purlins have replaced the conventional tubes and angles used earlier in roofing. Z‐ Purlins are fast gaining recognition in India due to their accuracy and wide range of applicability in various styles of roofing and side cladding. These are capable of meeting the needs of various establishments requiring large sized roofing such as Railway Platforms, Workshops, Factory Sheds, Warehouses and other Industrial Sheds.
AASHI Buildings offers designing, Fabrication and manufacturing services for C‐Purlins that gives strength to the roof. Whereas, C Purlins are economical and more suitable for manufacturing purposes and are highly in demand. AASHI is instrumental in manufacturing and designing these purlins as per the inputs or drawing specified by our clients.
ADVANTAGES OF “Z” AND “C” PURLINS
The main advantages of “Z” & “C” Purlins are:
When compared to Hot Rolled Angles, they save upto 25 – 30 % cost and a reduction in more than 40 % weight of structural steel
when compared to Tubular Purlins, they save upto 30‐40% in weight and 15% in costs
Erection of Purlins is much easier than others.
They are 4 or 5mm thick hot rolled angles sections that are used to prevent rigid frame members from twisting or buckling laterally under load. These are used on one side or both sides of the rafters/columns depending on the magnitude of the required restraining loads.