Long Span C Purlin Roof Design

For 2x4s purlins the posts are spaced in 4 feet distance.

Long span c purlin roof design.

The standard of purlin length will vary anywhere between 100 to 300 mm while the thickness will vary anywhere between 1 to 3 mm. High pressure zones kl 1 5 and 2 0 included. Here is the formula for calculation of a roof purlin. Flat roof span tables allow for a maximum roof pitch of 5º.

Flexospan provides standard even profile c purlins and c girts as well as custom profiles and punching patterns. Cpe 0 9 and cpi 0 2. Use recommended minimum roof pitches as specified by roof sheet supplier. C purlins and c girts.

Cos of live load dead load x cos of the purlin spacing x purlin span squared 8 x sm section modulus of the member x duration of load 1 15 in areas with snowfall x cr repetitive member factor of 1 15 where members are 24 on center or less fb fiberstress required. Safe roof purlins spans. We manufacture any component from 1 2 steel subgirts to 12 section up to 10 gauge. The number of supports beams or purlins affects the allowable span length.

Three equi spaced supports equal spans. Maximum roof slope is 5 for monoslope and 22 5 for pitched roof. Monoslope pitched single. Posts these span tables are designed for a minimum post size of 50 x 50 x 2 5mm up to a maximum height of 3 0m.

The c sections can also form part of the columns and rafters in these smaller applications. Spantec has prepared these tables for use by people skilled in the design and specification of the. If a steel purlin must span 24 feet between girders it should be at least 12 deep for girders calculate 3 4 inch of depth for every foot of span. Tables are given for 5 or more spans.

Arrangement of purlins by default purlin sections assume the slope of the roof they are supporting. If you want to know how to support roof purlins they are usually supported by 2 4 or 2 6 struts or posts. These tables are for spans in which purlins are lapped over each support where the lap length is 15 of the span. The safe spans below are suitable for sheds and class 1 structures with the following assumptions.

The spacing of purlins usually call for careful arrangement in the sense that it should follow the nodal pattern of the supporting trusses. Purlins rails eaves beams z e d p u r l i n s y s t e m s e a v e s be a m s z e d c e e s h e e t i n g r a i l s fl o o r c e e s design guide september 2014. Data is given in each table for. For purlins calculate 1 2 inch of depth for every foot of span.

Four or more equi spaced supports. Two supports one at each end double span. If a steel girder must span 24 feet between columns it should be at least 18 deep. Max roof span allowed 12m.

For outwards loads on equal continuous spans the bridging shown is required in the end spans.