Roof Purlin Design Example

The roof support system is a ridgepole and either rafters which run perpendicular from the top of the walls to the ridge or purlins which run parallel to the ridge.

Roof purlin design example.

Forces in roof systems as presented in chapter 5 of the new aisi. Design guide for cold formed steel purlin roof framing systems. Roof purlin are members used to directly support roof sheeting materials and could be made of timber or steel. Z purlin the zee or z purlin is shaped like a letter z.

The designis based on the maximum yeild strength mn fysx as stated in the aisc manual 13th ed. In timber construction purlins are nailed to the rafter or supporting trusses while in steel roof construction they are welded or bolted to the rafters or trusses by the means of cleats. Design of purlin solved problem by prof l agarwal. In traditional timber truss construction purlins rest on the principal rafters of the truss.

Design of roof purlins. The four steps in the general methodology of the component stiffness method are presented. Roof purlin design roof purlin design. C purlin cee or c purlins are shaped like a squared off letter c.

For example a roof purlin with no transversal element other than sheathing between the extremities on the compressed flange will have an unsupported length equal to its overall length. This spreadsheet is to be used to check the adequacy of roof purlins for a specified combination of loads. A common arrangement is a rafter and purlin system which combines purlins and rafters. First the development of forces requiring anchorage in purlin roof systems is discussed.

Its shape allows the purlin to overlap with others at the joints.