ROOFING SOLUTIONS PRODUCT CATALOGUE PURLINS & GIRTS PRODUCT CATALOGUE PURLINS & GIRTS JAN 2013 S&T029

Transcription

1 S&T029 JAN 2013 PRODUCT CATALOGUE PURLINS & GIRTS PRODUCT CATALOGUE PURLINS & GIRTS ROOFING SOLUTIONS

2 Contents HST Channel Purlins & Girts General Information...1 Sag Rod and Bracing Channel Layout...2 Speed Channel Layout...2 Standard Cleat Details & Hole Punching General Purpose Bracket Details...3 Section Geometry & Properties...5 Design Capacity Tables Design Information / Design Examples floor joist spans HST tophats & hst purlins - floor joist spans Single Span Double Span Spacing Spacing x x x x x x x x x / / / / / / / / / / / / / / HST Tophats HST Lapped Channel Purlins Introduction / Typical Construction Layout Design Capacity Tables Design Example...23 HST Tophat Purlins General Information...24 Sectional Properties / Typical Spans...25 Design Capacity Tables / Dimensions HST Purlin and Roof Selector Roof Selector Chart HST Purlins HST Purlin Floor Joist Span Tables Floor Joist Span Tables... Inside Back Cover Notes: 1. Loads 2. Durability 3. Bracing Spans are in metres and are based on controlling floor vibrations. The above spans are suitable for applied live loads of 5 kpa. HST purlins and tophats have a zinc weight of 275 gm/m2 and are suitable for use in an internal environment. Durability requirements should be checked for use elsewhere including subfloors. For increased performance where ceilings are not installed, we recommend providing a transverse brace (eg. ceiling batten - CB20 or similar, to the underside of the floor joists at 3 metre centres typical. ACKNOWLEDGEMENTS SPEED CHANNEL SYSTEM: The Speed Channel bracing technology is based on intellectual property of Dimond, a division of Fletcher Steel Limited, and is used for the HST purlin and girt system under license from Dimond, a division of Fletcher Steel limited. Sinclair Knight Merz have assisted in the development of the HST Channel Purlin System and production of the design manual. HST Tophat Purlin Tables and charts have been prepared by Harris Consulting Ltd DISCLAIMER This publication is intended to provide accurate information to the best of our knowledge in regard to HST Purlins and Girts. It does not constitute a complete description of the goods or an express statement about their suitability for any particular purpose. It is only intended as a general guide and not as a substitute for professional technical advice.

3 hst purlins & girts Introduction HST Steel Purlins & Girts are high strength lipped profile sections, manufactured by Steel & Tube to provide an economic solution for your building project and to assist with design. Sections are supplied punched and cut to length as required. Accessories including speed channel, bracing, sag rods and fastenings are offered to provide a practical structural system. HST Tophat Sections Steel & Tube HST Tophat Sections are an economical and lightweight product for roof purlins, wall girts and floor joists. Description Steel & Tube s galvanised cold formed steel HST Purlins & Girts, with accessories, make up part of a total system suitable to support a wide range of cladding materials, including profiled metal sheeting, sandwich panels and fibre cement sheeting. HST Purlin sections can also be readily adapted to a wide range of other application such as floor joists, ceiling support members and load bearing wall studs. Materials / Finish HST Purlins & Girts are rolled from galvanised high strength steel strip. Steel Thickness Grade Zinc Weight mm 500 (MPa) 275 gm/m mm 450 (MPa) 275 gm/m 2 Purlin braces and accessories are formed from galvanised Grade 250 steel. Performance HST Purlin and Girt loads are presented in limit state format consistent with AS/NZS 1170:2002 Structural Design Actions. Load capacities have been determined in accordance with AISI LRFD Cold-Formed Steel Design Manual, 1991 and confirmed by a full scale testing programme. AS/NZS4600:1996 has not been adopted, as the testing programme has demonstrated better correlation with the AISI reference above. The enclosed tables are generally conservative in relation to AS/NZS 4600:1996. Durability Provided HST Purlins, Girts and accessories are not exposed to moisture, service life will exceed 50 years, complying with the durability requirements of NZBC Approved Document B2. For applications within 1km of salt laden marine locations or severe industrial corrosive atmospheres, specialist advice should be sought. Length For ease of transportation and handling on site, the bundled length should be limited to 18 metres. Lengths exceeding 18 metres are subject to transport and handling facilities by special arrangement. Size Tolerances Web Depth ± 2 mm Flange Width ± 2 mm Lip ± 1 mm Hole Centres ± 1.5 mm Web / Flange Angle 88-93º Handling and Storage All sections and accessories must be kept dry during transport, stored on non-corrosive spacers above ground and covered to prevent moisture from entering between stacked sections. Should bundles become wet, they shall be broken open, dried with a cloth and restacked with separators to enable air to circulate. Bracing The HST Purlin & Girt system utilises standard brace / sag rod components or speed channel where required by the load tables. These shall be located in alternate bays, as shown on page 2, generally with a brace channel located immediately adjacent to both the eaves and ridge purlin. The galvanised HST brace channels are manufactured with end brackets custom fitted to suit the spacing. Standard sag rods are electro galvanised 12 mm diameter rod with double nuts and washers at each end. 16 mm diameter sag rods can be supplied to special order. All bracing components are fabricated from grade 250 (MPa) steel. Bracing should be located at the correct positions, as shown on page 2 to match pre-punched hole locations, otherwise lower load values may result. Load values with zero bracing have been included for the 100, 150 and 200 profiles, but generally it is recommended that at least one set of braces be provided, particularly when the HST Purlins will be used for access and temporary loading during construction.

4 Spacing hst purlins & girts Single bracing Sag Rod Purlin Bracing 6 gap Sag Rod 0.5L 0.5L Purlin Bracing Channel Purlin bracing layout Roofing HST Purlin HST Purlin Sag Rod Brace Channel located adjacent eaves purlin Brace Channel to alternative bays Sag Rod speed channel NB. Brace length equal to purlin spacing less 3 mm bracing assembly adjustable cleat 2mm End Cleat 100 x 32 x 1.2 m Purlin Purlin Bracing Standard Speed Channel Speed Channel HST Purlin Adjustable Channel bracing Brace Channel

5 standard cleat details purlin cleats HST f h 140 f h D dimensions purlin f g h HST HST HST HST HST HST HST g 82 g g HST 150, HST 200, HST 250, HST 300, HST 350, HST g h g h fastening to cleats f f 82 Cleats at internal supports Cleats at end supports 6-10 general purpose brackets Purlins HST 150, HST 200, HST 250, HST 300, HST 350, HST 400 Girts 6-10 c b 2 mm 18 φ mm holes 5 mm Rod 37 d a ultimate Joint shear Capacity dimensions purlin M12 bolts M16 bolts a b c d HST HST HST HST HST HST kn kn mm mm mm mm

6 standard hole location Single SPans HST L 0.5 L = 0.35 L One Sag Rod 0.35 L = HST Two Sag Rods HST 150, HST 200, HST 250, HST 300, HST 350, HST L 0.5 L g One Brace HST L 0.35 L 38 Two Braces 0.3 L 0.2 L 0.2 L 0.3 L g Three Braces HST 200, HST 250, HST 300, HST 350, HST 400 purlin dimensions g HST HST HST HST HST HST HST Hole Sizes Bolt Round Elongated M12 14 mm 14 x 18 mm M16 18 mm 18 x 22 mm Note All holes round unless specified otherwise. Purlins and Girts can be supplied with additional holes at other locations if required.

7 Section Geometry & Properties b b x S x L b x S x L p d 1 x S x L p b 1 p d 1 q b 1 d d 3 d d 2 d 4 d d 3 Profile I Section Geometry Profile II Profile III Profile Section MK d b t p q b 1 d 1 d 2 d 3 d 4 x L x S Area A S Mass mm mm mm mm mm mm mm mm mm mm mm mm mm 2 kg/m I 100/ / / II 150/ / / III 200/ / / / / / / / / / Notes 1. A S = Gross Section Area 2. All dimensions are normal within rolling tolerances Section Properties Section Area Weight Second Moment Section radius of Form Torsion Warping MK A S w t of Area Modulus gyration Factor Constant Factor mm 2 kn/m I x I y Z x Z y r x r y Q J I w 0 6 mm mm mm mm 3 mm mm mm mm 6 100/ / / / / / / / / / / / / / / / Notes 1. All section properties are for the gross section 2. Form factor based on F=300 MPa

8 design capacity tables ultimate Uniformly Distributed Load - single span HST 100/12 HST 100/15 HST 100/19 HST 150/12 HST 150/15 HST 150/18 (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) Span 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF Note: Tables assume one flange continuously restrained by roof or wall cladding. 6

9 ultimate Uniformly Distributed Load - single span HST 200/12 HST 200/15 HST 200/18 HST 250/13 HST 250/15 (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) Span 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF Note: Tables assume one flange continuously restrained by roof or wall cladding.

10 design capacity tables ultimate Uniformly Distributed Load - single span HST 250/18 HST 300/15 HST 300/18 HST 350/18 HST 400/20 (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) Span 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF Note: Tables assume one flange continuously restrained by roof or wall cladding. 8

11 ultimate axial Load - concentric HST 150/12 HST 150/15 HST 150/18 HST 200/12 HST 200/15 φnc φn EX φnc φn EX φnc φn EX φnc φn EX φnc φn EX (kn) (kn) (kn) (kn) (kn) Span 0B 1B 2B Fr 0B 1B 2B Fr 0B 1B 2B Fr 0B 1B 2B Fr 0B 1B 2B FR Note: Tables assume one flange continuously restrained by roof or wall cladding. 9

12 design capacity tables ultimate axial Load - concentric HST 200/18 HST 250/13 HST 250/15 HST 250/18 φnc φn EX φnc φn EX φnc φn EX φnc φn EX (kn) (kn) (kn) (kn) Span 0B 1B 2B Fr b b b Fr b b b Fr b b b FR Note: Tables assume one flange continuously restrained by roof or wall cladding. 10

13 ultimate axial Load - concentric HST 300/15 HST 300/18 HST 350/18 HST 400/20 φnc φn EX φnc φn EX φnc φn EX φnc φn EX (kn) (kn) (kn) (kn) Span 1B 2B 3B Fr b b b Fr b b b Fr b b b FR Note: Tables assume one flange continuously restrained by roof or wall cladding. 11

14 design information Design Capacity Tables The loads given in these tables are the design load capacity for ultimate limit state ( ) in kilonewtons per metre of span (kn/m) for loads uniformly distributed along the span. For other load situations, specific design is required. Loads for intermediate spans may be determined by linear interpolation. Strength reduction factors are included in the design load capacity and have been determined from AISI LRFD Cold- Formed Steel Design Manual 1991 as follows: Bending φ = 0.9 Axial Load φ = 0.85 The self weight of HST purlin is not included in the load tables and should be calculated along with other dead loads. The tables are applicable to both inward and outward loads, ie. loads acting towards the centre of the section and away from the centre of the section respectively. In both cases the tables assume full lateral restraint is provided to one flange by roof or wall cladding, with normal screw fixings. For inward loads fully restrained values may be used, while for outward loads braced values are appropriate. Where HST purlins or girts are to be used in situations where at least one flange is not continuously laterally restrained by roof or wall cladding, then the design loads must be reduced. Specific guidance should be sought from Steel & Tube. The serviceability load ( ) is the uniformly distributed load (kn/m) at which the midspan deflection equals span/150. This corresponds to the serviceability limit recommended for roofs with brittle cladding under wind load only. Deflections at other loadings can be determined by direct proportion and corresponding serviceability limit states checked accordingly. load combinations The Limit State method of design is recommended with combinations of factored loads for each limit state in accordance with AS/NZS1170:2002. This should include dead, live, wind, snow and earthquake loads. For walls, provided the maximum spacing between brace struts / sag rods is limited to 3000 mm and the wall cladding is screw fixed to the girts, the dead load of the girts and cladding may be assumed to be carried directly by the bracing system. Accordingly, the girts may be designed for face loads only. The design engineer should ensure that the loads in the bracing system can be supported either by an eaves member or directly by the foundations. Axial Loads Where HST purlins are required to support axial loads, as well as bending loads, such as when they act as bracing struts or are required to transmit end wall loads to the roof bracing system, then the interaction equation set out below, as adopted from the AISI LRFD Cold-Formed Steel Design Manual 1991, is recommended. N* + C mx W L * 1.0 φ N C α nx N* = Applied ultimate limit state axial load (kn) φ N C = Design load capacity for members subject to axial compression (kn) W L * = Applied ultimate limit state uniformly distributed load about the X axis (kn/m) = Design load capacity for uniformly distributed load (kn/m) C mx = Load coefficient = 1.0 for a member subject to uniformly distributed load α nx = (1 - N* /φ N EX ) φ N EX = Euler buckling capacity about the X axis, as given by the design capacity axial load table (kn) Note the HST purlin is assumed to have zero distribution load about the Y axis of bending. Where biaxial bending occurs, then specific guidance should be sought from Steel & Tube. Loads are assumed to act about the major axis of symmetry. For roof pitches over 10º, the design engineer shall allow for the resultant force in the plane of the roof due to dead, live and snow loads. 12

15 Design examples The following design examples are based on loads calculated in limit state format, in accordance with AS/ NZS 1170:2002 Example 1 - Roof The example below considers a purlin in a typical portal frame building, with lightweight metal cladding. Limit State Loads from AS/NZS 1170:2002 Dead Load G = 0.15 kpa Live Load Q = 0.25 kpa Ultimate Wind Load (W U ) p z = 0.69 kpa Ultimate Wind Load (W U ) p z = 0.44 kpa Serviceability Wind ( ) p z = 0.46 kpa Serviceability Wind ( ) p z = 0.29 kpa Geometry Span L = 9.0 m Purlin Spacing S = 1.9 m a) Check Serviceability Limit State (deflection) using values in Design Capacity Tables. Serviceability Load Combinations G + ψ l Q = x 0.25 = 0.15 kpa = kpa = 0.29 kpa calculate the maximum distributed loads * (wind) = 1.9 x 0.46 = 0.87 kn/m * (dead) = 1.9 x 0.15 = 0.29 kn/m Check wind load at deflection limit of L/150 From charts for HST 250/15. = 0.95 kn/m > W L * HST 250/15 OK Check dead load at deflection limit of L/300 = 0.5 x 0.95 = 0.48 kn/m > W L * HST 250/15 OK b) Check Ultimate Limit State using values in Design Capacity Tables. Ultimate Load Combinations 1.35G = 1.35 x 0.15 = 0.20 kpa 1.2G + 1.5Q = 1.2 x x 0.25 = 0.56 kpa 1.2G + W U = 1.2 x = 0.62 kpa 0.9G + W U = 0.9 x = 0.56 kpa Calculate the maximum distributed loads W L * = 1.9 x 0.62 = 1.18 kn/m W L * = 1.9 x = kn/m Top flange of the purlin is restrained by the sheeting material, therefore consider the purlin fully restrained for downward loading. (FR) = 1.84 kn/m > W L * HST 250/15 OK For upward loading, use braced case with one brace (1B) = 1.13 kn/m > W L * HST 250/15 OK Use HST 250/15 at 1.9 m spacing, with 1 brace at midspan. Example 2 - Wall The example below considers a girt in a typical portal frame building, with lightweight metal cladding. Limit State Loads from AS/NZS1170:2002 Ultimate Wind Load (W U ) p z (in) = 0.86 kpa Ultimate Wind Load (W U ) p z (out) = 0.43 kpa Serviceability Wind ( ) p z (in) = 0.57 kpa Serviceability Wind ( ) p z (out) = 0.28 kpa Geometry Span L = 10.0 m Girt Spacing S = 1.8 m a) Check Serviceability Limit State (deflection) using values in Design Capacity Tables. Serviceability Load Combinations (in) = 0.57 kpa (in) (out) = 0.28 kpa (out) calculate the maximum distributed loads * (wind) = 1.8 x 0.57 = 1.03 kn/m (in) check wind load at deflection limit of L/150 From charts for HST 300/15 = 1.18 kn/m > W L *(in) HST 300/15 OK b) Check Ultimate Limit State using values in Design Capacity Tables. Calculate the maximum ultimate limit state distributed loads W L *(in) = 1.8 x 0.86 = 1.55 kn/m (in) W L *(out) = 1.8 x 0.43 = 0.77 kn/m (out) Outer flange of the girt is restrained by the sheeting material, therefore the girt is considered fully restrained for inward loading. (FR) = 2.02 kn/m > W L *(in) HST 300/15 OK For outward loading, use braced case with one brace. (1B) = 1.32 kn/m > W L *(in) HST 300/15 OK Use HST 300/15 at 1.8 m spacing, with 1 brace at midspan. 13

16 Design examples Example 3 - axial Consider the purlin of example 1 as a roof bracing strut, with an ultimate axial load N* due to longitudinal wind. Design Axial Load N* = 34.0 kn From example 1 W L * = 1.18 kn/m From example 1 W L * = kn/m Check Ultimate Limit State using values in Design Capacity Tables. a) Try HST 250/15 with 3 braces From Design Capacity Tables Design axial load capacity φn C = 65.5 kn Euler buckling capacity φn EX = kn Design load capacity (FR) = 1.84 kn/m Design load capacity (3B) = 1.69 kn/m C mx = 1.0 α nx = 1 - N*/φ N EX = / = N* φ N C + C mx W L * (FR) α nx b) Try two HST 250/15 (with 1 brace), purlins back to back. Ultimate loads to purlins N* = 17.0 kn (per purlin) W L * = 0.59 kn/m (per purlin) W L * = kn/m (per purlin) From Design Capacity Tables Design axial load capacity φn C = 38.4 kn Euler buckling capacity φn EX = kn Design load capacity (FR) = 1.84 kn/m Design load capacity (1B) = 1.13 kn/m C mx = 1.0 α nx = 1 - N*/φ N EX = / = N* φ N C + C mx W L * (FR) α nx = x x = 0.81 < 1.0 2HST 250/15 OK N* φ N C = x x = 1.37 > 1.0 No Good + C mx W L * (3B) α nx = x x = 1.35 > 1.0 No Good N* φ N C + C mx W L * (1B) α nx = x x = 0.98 < 1.0 2HST 250/15 OK Use two HST 250/15 back to back (with 1 brace), for the purlins acting as roof bracing struts. 14

17 lapped Purlins introduction HST Lapped Purlins Lapped HST purlins provide the advantage of increased load carrying capacity and reduced deflections when compared to single span HST purlins. The following tables replace the Uniformly Distributed Load Single Span tables on pages 6, 7 and 8 of the design guide, when lapped HST purlins are used. For all other properties refer to the design guide. The tables are based on a lap length of 5% of span length (and a minimum length of 300 mm) each side of the support. Design capacity tables Load capacities have been determined in accordance with AISI LRFD Cold-Formed Steel Design manual, 1991 and confirmed by a full scale testing programme. The loads given in these tables are the design load capacity for ultimate limit state ( ) in kilonewtons per metre of span (kn/m) for loads uniformly distributed along the span. For other load situations, specific design is required. Loads for intermediate spans may be determined by linear interpolation. The self weight of the HST purlin is not included in the load tables and should be calculated along with other dead loads. Tables are included for end spans and internal spans. A greater load capacity is available for internal spans because of the continuity at both ends. Because the maximum moment for the end span occurs over the first support, the internal HST purlin is required to carry the same moment and the load tables are not applicable. Consequently the purlin size and number of braces for the first internal purlin or girt must be at least equal to the end purlin requirements. Refer to the diagram below. The tables are applicable to both inward and outward loads. In both cases the tables assume full lateral restraint is provided to one flange by roof or wall cladding, with normal screw fixings. Contrary to single span HST purlins, braced values must be used for both inward and outward loads. Fully restrained values are not applicable for lapped HST purlins unless the compression flange is continuously fully restrained (note the compression flange changes from one flange to the other within the span). Where HST purlins or girts are to be used in situations where at least one flange is not continuously laterally restrained by roof or wall cladding, then the design loads must be reduced. Specific guidance should be sought from Steel & Tube. The serviceability load ( ) is the uniformly distributed load (kn/m) at which the midspan deflection equals span/ 150. Limitations The Tables are not applicable when the length of adjacent spans differ by more than 10%, nor when the loading varies by more than 50% between adjacent spans. The tabulated values are for end and internal spans where there is a lap over each internal support. They are not applicable when a HST purlin is continuous over a support without a lap. Purlin spacing is limited to 2.4 metres when the standard bracing channel is used. Specific guidance should be sought from Steel & Tube when these requirements are not satisfied. Use end span tables Use internal span tables Use end span tables Purlin/Girt lap over each internal support Purlin/Girt size and bracing as end span Purlin/Girt size and bracing as end span 15

18 HST Lapped purlins with Single bracing Sag Rod typical construction layout Purlin Bracing Sag Rod 0.5L Gable End Rafter Spacing 0.5L Purlin Bracing Channel Purlin L 0.05 L < L < 300 Lapped Purlins - End Span L 0.05 L < L < L < L < 300 Lapped Purlins - Internal Span Hole positions for intermediate braces as for the single span purlins Cleat welded to rafter Spacers same thickness as cleat Note: Minimum bolt size M16 for lapped purlins 16

19 design capacity tables ultimate Uniformly distributed load - lapped end span HST 150/12 HST 150/15 HST 150/18 HST 200/12 HST 200/15 (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) Span 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF Note: 1. Use this table only for external spans with a lap at one end. 2. Lap length to be the greater of 5% of the longer adjacent span or 300 mm each side of the support. 3. Tables assume one flange continuously restrained by roof or wall cladding 17

20 design capacity tables ultimate Uniformly distributed load - lapped end span hst 200/18 HST 250/13 HST 250/15 HST 250/18 (kn/m) (kn/m) (kn/m) (kn/m) Span 0B 1B 2B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF Note: 1. Use this table only for external spans with a lap at one end. 2. Lap length to be the greater of 5% of the longer adjacent span or 300 mm each side of the support. 3. Tables assume one flange continuously restrained by roof or wall cladding 18

21 ultimate Uniformly distributed load - lapped end span hst 300/15 HST 300/18 HST 350/18 HST 400/20 (kn/m) (kn/m) (kn/m) (kn/m) Span 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF 1B 2B 3B FR DEF Note: 1. Use this table only for external spans with a lap at one end. 2. Lap length to be the greater of 5% of the longer adjacent span or 300 mm each side of the support. 3. Tables assume one flange continuously restrained by roof or wall cladding 19

22 design capacity tables ultimate uniformly distributed load - INTERNAL SPAN HST 150/12 HST 150/15 HST 150/18 HST 200/12 HST 200/15 (kn/m) (kn/m) (kn/m) (kn/m) (kn/m) Span 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF 0B 1B 2B FR DEF Note: 1. Use this table only for internal spans (excluding the first internal span) with laps at both ends. 2. Do not use this table for first internal span. Use purlin size and number of braces as end span. 3. Lap length to be the greater of 5% of the longer adjacent span or 300 mm each side of the support. 4. Tables assume one flange continuously restrained by roof or wall cladding 20