CI/SfB (28) Hh2 January Lattice beam technical manual. Joists, trusses and complete frame installation service

Transcription

1 CI/SfB (28) Hh2 January 206 Lattice beam technical manual Joists, trusses and complete frame installation service

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3 Contents MLB : Investing in quality and service 3-4 Installation 5 Product range 6-0 Features and benefits 6-7 Product range 8-9 Heavy duty range 0 Roof beams -8 Metal roof systems -2 Traditional roof systems 3 Green roof systems 4 Complete lightweight systems 5 Over-roof systems 6 Eaves cantilever systems 7-8 Ceiling and service supports 9-20 Ceiling and service support systems 9 Walk on ceiling systems 20 Floor beams 2-22 Traditional floor systems 2 Mezzanine floor systems 22 Fixing details Typical fixing details Chord and bridging details Chord details 27 Bridging details 28 Design examples and load tables Design examples Load tables - Parallel beams Services and design software Services and general notes 36 Software 37 2

4 Quality and service Quality and service Investing in quality and service Metsec plc Metsec plc is the UK s largest specialist cold roll-forming company, providing structural steel components for the UK construction and manufacturing industries. We have been established for over 75 years and are based in Oldbury in the West Midlands. Today, Metsec are part of the Profilform Division of voestalpine - the world s largest manufacturer of cold roll-formed sections, with a global network producing over 800,000 tonnes of cold rolled steel per annum. We focus on adding value through expert design, precision manufacturing and on-time, in-full product delivery. Our aim is to provide excellent service and quality products that offer our customers cost effective solutions. Please Note As of April 202, Metsec Lattice Beams Ltd are no longer part of the Metsec plc group. We are now an independent trading company. Metsec Lattice Beams Lightweight steel lattice beams were first introduced by Metsec in the 950 s and their inherent advantages very quickly established the product as the first choice for structurally sound, cost effective construction. Since this introduction, the Metsec policy of continual research and development has ensured that quality and technical properties have improved over the years and availability of type has increased in parallel with development in building technology and architectural styles. Metsec Lattice Beams Ltd offer a wide range of joist and truss solutions pre-engineered off site. We can achieve spans of up to 40m and all of our designs give optimal levels of structural performance in roof, floor or any other application where light weight and long span performance is important. All sections are designed in accordance with BS :998. Quality MLB operates strict design and quality procedures through a Quality Management System which covers both our design and manufacturing operations. This commitment to quality ensures that we provide the highest levels of performance throughout our operations, ensuring the highest level of customer satisfaction. Design Our market-leading LatticeSPEC design software provides cost effective solutions to maximise the design efficiency of structures. Comprehensive technical support is provided by our design office. The latest version of LatticeSPEC offers the unique advantage of producing complete profiles/sections of joists and trusses in.dxf format, saving the professional team valuable time when specifying our products. For full details on our technical support service and how to obtain a free copy of LatticeSPEC please refer to page 39. Re-use and recycling Steel is one of the World s most recycled materials. According to the British Constructional Steelwork Association (BCSA), recovery rates for steel components from building demolition sites are 84% for recycling and 0% for re-use*. This gives a total potential recovery and re-use factor of steel from buildings of an incredible 94%. * BCSA publication no. 35/03 3

5 Product range Quality and service CE Marking Accreditation Metsec Lattice Beams Limited has attained CE marking accreditation to Execution Class 3 (EXC 3) of BS EN CE Marking Accreditation to Execution Class 3 (EXC 3) of BS EN Since July st 204 CE marking became compulsory for all manufacturers of structural steel components in the UK. Metsec Lattice Beams Limited's Factory Control Production (FPC), management systems and welding procedures have all been certified by BSI to comply with stringent CE marking standards. CE marking is a regulatory mark applied by the manufacturer. It is a declaration that the product conforms with the relevant technical specifications and that the required assessment procedures have been complied with. CE marking accreditation demonstrates our commitment to delivering premium quality products to the market. 4

6 Product range Quality and service Installation Service As well as being one of the UK s largest manufacturers and suppliers of lightweight lattice beams and trusses we also provide a complete design and installation service. Furthermore if our Lattice Beams are part of your specification we can offer the installation of the complete Steelwork Package inclusive of cladding and roofing. Our highly skilled and experienced engineers will work closely with your chosen architect/structural engineer to create a design that meets and exceeds all criteria and ensures your project gets delivered on time and within budget. This attention to quality runs through to the manufacture and installation. With significant experience of working closely with architects, designers and contractors, Metsec Lattice Beams can advise on the best and most efficient way to deliver your project. From developing installation plans, fabrication to the highest standards, logistics, delivery and site management, Metsec Lattice Beams is your preferred partner. We ensure that all lattice beam and associated ancillary steel installations comply with engineer s drawings and that the final installation is checked and certified. We are CE accredited and CHAS approved confirming our commitment to provide a quality service including final installation. All site work conforms to latest health and safety requirements including method statement and personnel training. Proud to be a trusted partner to many of the UK s leading construction companies, Metsec Lattice Beams has a strong track record in the safe delivery and installation of lattice beams across the UK and Europe for public and private sector clients. To take advantage of our experienced design and installation service: your project details to sales@metseclatticebeams.com Complete our online request form Phone our technical advisory service directly on +44 (0) We are members of: 5

7 Product range Product range Features and benefits Metsec lattice beams are designed and manufactured to BS 5950-: 2000 and 5: 998 and are formed from two cold rolled chord sections with a central web joining the two together. Typical profiles are shown on page 8-9. The chord sections are all formed from high yield steel to BS EN 049-2: 996 and have a minimum yield strength of 355N/mm². The web members are usually constructed from solid bar on the smaller joists or hollow section for the deeper joists and trusses. These are joined to the chord sections by CO 2 shielded arc welding in a pre-set jig to ensure dimensional accuracy. This process allows for the design and manufacture of a vast range of profiles, from simple parallel joists through to complex double curve, wave trusses, to suit almost any application. Long span A typical Metsec lattice beam can weigh up to 50% less than its hot rolled counterpart and yet still achieve spans of up to 40m without the need for intermediate support columns - which can allow designers greater flexibility when working to optimise internal space. Internal space can also be optimised by passing services through the web of the lattice rather than having to suspend them underneath causing a significant loss of headroom. Services - excellent head height The open web configuration of Metsec lattice beams allows for the simple passage of services through the web lacings. However, the web lacings will not necessarily align unless this is specifically requested. Where special duct openings are required these should be positioned near the centre of the beam where shear is less critical. Please consult the Metsec Lattice Beam Technical Department for further information

8 Product range Product range Optimised wall/ceiling junctions Due to the slim profile offered by Metsec lattice beams excellent strength to weight ratio, beams can be incorporated at the head of partitioning and drylining systems without any requirement for separate boxing in or encasement. This allows continuous and parallel studwork to full ceiling height, simplifying and accelerating installation, maximising use of space and optimising aesthetics. Pre-engineered offsite - to ease site access Where site access is a consideration, bolted joints can be used. The joists are then assembled on site using H.T. grade 8.8 bolts to join the sections. Flush site joints to the top and/or bottom chords are also available. Factory joints may occasionally be incorporated into joists. They will always consist of an appropriate jointing arrangement with a full profile fillet weld. Finish as flexible as your design All Metsec lattice beams are supplied shot blasted and factory finished with a Zinc Phosphate primer as standard. Other painted finishes, including any standard RAL colour, are available upon request. This feature is particularly important if it is desired to leave the lattice members exposed as part of a feature internal roof structure. A hot-dipped galvanised finish is also available. This is recommended for cold roofs and roofs with limited access or exposed locations. Timber - for rapid, secure fixings Flush fitting standard Vac-Vac WR treated timber can be supplied if required in the top and/or bottom chords of all beams. The timber is rigidly attached to the chords by shot-fired pins at 600mm staggered centres. This offers a simple fixing medium for certain floor/roof finishes, timber firrings and/or plasterboard ceilings

9 Product range Product range Product range Parallel beam Roofs suitable for use with flat roofs or sloping roofs where the lattice beams can be laid to falls. They can also be used as long span purlins and are suitable for use with most external finishes from lightweight metal sheeting through to heavier constructions with tiles on battens or decking. Floors suitable for use as joists in all types of flooring including timber, pre-cast concrete slabs or profiled metal decking with in-situ poured concrete. Pitched truss Pitched trusses are suitable for all types of duo-pitch roof construction and can be used with most external finishes from lightweight metal sheeting through to heavier constructions with tiles on battens or decking. Tapered truss Tapered trusses are suitable for all types of mono-pitch roof construction. They can be used with most external finishes from lightweight metal sheeting through to heavier constructions with tiles on battens or decking. Inverted truss Inverted trusses are generally used on low pitched roofing with timber or metal decking and built up finishes. When used in conjunction with Metsec Z-section purlins the design of deep valley gutters can be simplified. Parallel pitched beam Parallel pitched beams are suitable for all types of duopitch roof construction providing extra headroom over that afforded by the pitched truss. They can be used with most external finishes from lightweight metal sheeting through to heavier constructions with tiles on battens or decking

10 Product range Product range Curved truss Curved trusses can provide an aesthetically enhanced roof profile. When used with a standing seam roof this type of construction is easy to detail and install giving a very low maintenance roof. Curved beam Curved beams provide an aesthetically enhanced roof profile construction providing extra headroom over that afforded by the curved truss. When used with a standing seam roof this type of construction is easy to detail and install giving a very low maintenance roof. Double curved (wave) truss Double curved trusses provide an ideal solution for the designer working with modern multi-curved roof structures. When used in conjunction with Metsec SFS framing system the structure can be built to a constant datum and can be used with all typical external finishes Inverted curved truss Inverted curved trusses offer designers a simple solution when specifying a single curve roof structure. This can be used to enhance the appearance of roof structures and is frequently specified with standing seam roofing to create a smooth appearance. In many of the applications listed above Metsec Z-section purlins provide an excellent design solution to carry the external finish. Similarly the wide range of Metsec mezzanine floor C-sections can provide a range of system solutions for the designer

11 Product range Product range Heavy duty range Metsec lattice beams are the UK s largest specialist manufacturer of steel lattice beams and trusses. All beams are detailed and fabricated to suit the clients requirements. Typical truss profiles are shown on the previous pages, however, we are not restricted to these and the potential shape and scope of the lattice trusses is endless. On many occasions the truss profile is developed to suit Architectural requirements. Our 3000m 2 manufacturing facility has been custom developed and laid out in order to determine the most efficient flow of materials. This ensures not only highly efficient production methods but improved levels of consistency and quality. Trusses are regularly produced with span of up to 40m and depths up to 4.5m. Lattice beams and trusses can be fabricated to customers design and specifications. We regularly model and fabricate lattice beams and trusses using SHS, RHS and UC sections. All fabrications are covered with our CE marking accreditation. This accreditation allows fabrications of up to and including Execution Class 3 (EXC 3) of BS EN Lattice beams are not only used for roof and floors but are also ideal for long span ceiling supports, pipe bridges and service support gantries

12 Roof beams Roof beams Metal roof systems Metsec lattice beams can offer the ideal solution for supporting a wide variety of roofing systems due to their excellent strength to weight ratio. A typical Metsec lattice beam can weigh up to 50% less than its hot rolled counterpart and yet still achieve spans of up to 40m without the need for intermediate support columns which can allow designers greater flexibility when working to optimise internal space. Internal space can also be optimised by passing services through the web of the lattice rather than having to suspend them underneath causing a significant loss of headroom. Similarly their aesthetic properties mean that they can be supplied painted and left exposed as part of a feature internal roof structure. In addition to the direct reduction of the environmental footprint of a construction project by virtue of their lighter weight, lattice beams can also help to reduce the environmental footprint of the project by using off-site fabrication to speed up the construction process of the roof as the lighter sections can generally be transported and handled more efficiently on site. Curved truss with structural deck Metsec curved trusses can be used to support structural decks with a suspended ceiling. The natural open web of the truss allows for the simple passage of services. Leasowes Medical Centre, West Midlands

13 Roof beams Roof beams Parallel beam laid to fall Metsec parallel beams can be used to support Z-section purlins bolted to cleats pre-welded to the top chord of the beam. Liner tray, insulation and metal deck provide the weather-proof layer and are fixed to the Z-section purlins. Vauxhall Sales Centre, West Midlands Pitched truss with flush-fitting Z-section purlins Metsec pitched trusses are supported on a hot rolled steel structural frame. Z-section purlins are fitted flush to the top chord of the pitched trusses to support standing seam roof, or similar. Flush fitting Z-section purlins are often used to minimise the overall construction depth of the roof. Staplehurst Medical Centre, Kent 2 2 2

14 Roof beams Roof beams Traditional roof systems Parallel beam used as purlin Metsec parallel beams can be used as long span purlins supported on load bearing masonry walls. In this application timber firrings are fixed directly to flush fitting timber inserts in the top chord of the beam. Timber roof rafters are then fixed to the timber firrings to support counter battens, underlay, tiling battens and tile or slates. Firrings by others Timber insert for nailability Pitched truss used to support timber purlins Traditional timber purlins can be supported on a Metsec pitched truss. Ply or similar sheathing is then used to support weatherproofing layers of battens, underlay and roof tiles or slates

15 Roof beams Roof beams Green roof systems Parallel beams used to support steel decking with green roof surfacing Metsec parallel beams can be used to support a structural deck, membrane, substrate and Sedum roof. These beams can be up to 50% lighter than hot rolled beams and use far less steel with considerably less environmental impact than other systems. Smithswood School, Solihull 4 4 4

16 Roof beams Roof beams Complete lightweight systems Metsec lightweight trusses, combined with SFS stand-alone walling systems, are becoming ever more popular for constructing complete structures. The Metsec Lattice Beam and Framing Divisions work together closely to provide total construction solutions for the developer. The complete wall and roof solution is frequently installed through the Metsec Framing Division s approved installer network. This adds to the complete, one-source nature of the package in keeping with the demands of the modern construction industry. P a t c h i n g L o d g e, B r i g h t o n Metsec double curve roof system Metsec lightweight trusses and Z-section purlins can also be combined with stand alone, light gauge, cold rolled Steel Framing Systems (SFS) to provide complete one-source building solutions 5 5 5

17 Roof beams Roof beams Over-roof systems Building services Ring beams Where existing flat roofs are starting to fail or require upgrading, one option to consider is the creation of a new pitched, or curved, over-roof which can be constructed quickly and cost effectively using lattice trusses. The lightweight lattice over-roofing system avoids the need to strengthen the existing roof structure and can give an existing building a much needed facelift - typically at a fraction of new build costs. The new trusses can be spaced at much wider centres than other over-roof systems, which results in fewer penetrations and fixings into the existing structure. the building and provide a range of benefits for the building owner, including improved water run-off and enhanced building insulation. The additional space created under the new structure can also be used to house building services making usable space available elsewhere in the structure. The Metsec lattice team have gained considerable expertise in the design of trusses for use in overroofing projects both large and small. The new lattice trusses are installed to span across St. Lukes School, Portsmouth

18 Roof beams Roof beams Eaves cantilever systems Top chord cantilever This detail can be used for small span cantilevers of up to m. Stiffener angles can be welded to the sides of the top chord, if required, to provide an economic cantilever solution. Cantilever bolted to welded stub-post This detail can be used for medium span cantilevers of up to 2m. The cantilever arm is bolted to the end post which is supplied welded into the end of the lattice. Since the cantilever roof element does not require an insulation layer the line of the supporting cantilever eaves structure is correspondingly raised to support the top sheet

19 Roof beams Roof beams Loose, bolt-on cantilever This detail can be used for large span cantilevers of over 2m. The cantilever arm extends into the building to provide an adequate backing span and is bolted on to the top chord of the lattice

20 Ceilings and service supports Ceilings and service support systems Metsec parallel lattice beams are the ideal solution for the support of ceiling structures within existing buildings. Whether the ceiling is a simple suspension from a secondary grid of C-sections or is walk-on and supported from the bottom chord of the lattice beam, Metsec has a range of solutions. Lattice beams are ideal for clean rooms, data halls, telecommunications facilities, retail units and secure locations where long, unobstructed spans are essential and where their light weight can minimise the load on to the existing structure. They can also allow the passage of services through the lattice s web without any loss of head room or need for exposed pipework which can form a potential dust trap. Metsec lattice primary members together with Z or C-section secondary members provide a cost effective solution to ceiling/service support requirements. Metsec parallel beam Used with secondary C-sections to support a suspended ceiling. In the illustration shown, the ability to run split-level ducting through the lattice without any loss of internal headroom is clearly demonstrated. A further benefit is that future changes to the building services can easily be accommodated by running piping or ducting through the lattice. Service support/pipebridge Metsec provide an economic system to form pipebridge and service supports. Lightweight lattice joists are provided in pairs and braced together to form spans of up to 40m. The majority of pipebridges are supplied with a galvanised finish for external applications. However, various paint specifications are also available where required. Millennium Dome, London Millennium Dome, London 9 9 9

21 Walk-on ceiling systems Ceilings and service supports Metsec parallel beam supporting walk-on ceiling Metsec parallel ceiling support beams can be used for walk-on ceiling applications. Metsec lattice beams are frequently used to create a support structure for walk-on ceilings in which an interlocking system of steel faced planks is used to create a load bearing ceiling construction. These systems are particularly popular in the creation of clean rooms where sealing the joints of these planks creates a closed ceiling void in which the high level mechanical and electrical services can be installed without the need for secondary floors or complex support systems. Ceiling and service support structure These systems provide an excellent solution to the location of services and are specifically designed to allow maintenance engineers to walk on top of the ceiling system. This facilitates the easy access to services and components without the need for the access equipment normally associated with more basic ceiling installations. The two photographs to the left show projects where Metsec lattice beams are employed in walk on ceiling constructions. Clean room ceiling support structure

22 Floor beams Floor beams Traditional floor systems Metsec lattice joists offer a simple solution for the construction of both conventional and mezzanine floors due to their excellent strength to weight ratio. This means that a typical lattice joist can weigh up to 50% less than their hot rolled counterparts. Of great importance to the designer is the fact that the internal space can be optimised by passing services through the web of the lattice joists rather than having to suspend them underneath causing a significant loss of headroom. In addition to the direct reduction of the environmental footprint of a construction project by virtue of their lighter weight, lattice beams can also help to reduce the environmental footprint of the project by using off-site fabrication to speed up the construction process of the floor as the lighter sections can generally be transported and handled more efficiently on site. Similarly, the ability to insert flush fitting timber sections into the top and bottom chords offers a simple medium for the fastening of floor decking and/or plasterboard ceilings. Traditional floors Metsec parallel floor joists at 600mm centres with the floor decking nailed to the top chord and two layers of plasterboard to the bottom chord. White Rose Shopping Centre, Leeds. 2

23 Floor beams Floor beams Mezzanine floor systems Mezzanine floors Metsec parallel floor joists with C-sections supporting floor decking. The photograph below shows a project where 7m span lattice joists were designed to carry storage loadings. 22 Zurich Insurance, Wiltshire

24 Fixing details Fixing details Typical fixing details F Shoe fixing to concrete padstone F2 Beam laid to fall on sloping shoes F3 Full depth fixing to concrete padstone F4 Full depth seating with beam extended F5 Beam fixing to internal wall F6 Beam laid to fall with full depth seat 23

25 Fixing details Fixing details F7 Fixing to concrete face with loose angle cleats F8 Shoe fixing to hot rolled steelwork F9 Shoe fixing to hot rolled steelwork (pair) F0 Full depth fixing to the web of hot rolled steelwork F Full depth fixing to hot rolled steelwork F2 Fixing to internal hot rolled steelwork 24

26 Fixing details Fixing details Typical fixing details F3 Beam to column flange fixing F4 Beam to column fixing with plate welded to column F5 Beam to beam trimmer fixing F6 Typical bridging fixing detail F7 Bracing fixing detail Note F and T details illustrate a typical range of connections that are available. Other connections can be fabricated to suit site conditions. 25

27 Fixing details Fixing details T Full depth fixing with bearing plate T2 Purlin to truss fixing T3 Truss to column flange fixing T4 Standard shoe fixing to hot rolled steelwork T5 Beam to truss trimmer fixing T6 Standard shoe fixing to concrete padstone 26

28 Chord and bridging details Chord and bridging details Chord details Nominal dimensions Chord y Area rxx ryy Ixx Iyy Zxx Zyy type mm cm 2 cm cm cm 4 cm 4 cm 3 cm MB y x x MD y 50 x x MG 5 y 75 x x MJ 5 y 00 x x ML 6 y 00 x x

29 Chord and bridging details Chord and bridging details Bridging details Bridging Bridging is recommended during the construction period to enable the beams to support the construction loads, and to hold the beams at the centres and positions indicated on the plans. However, when construction loads are deemed to be light, bridging can be omitted at the discretion of the Metsec Lattice Beam Technical Department. Bridging Maximum spacing of bridging for chord sections (m) Type MB MD MG MJ ML Bridging consists of steel angles connected to the top chord of the lattice. Bridging may also be required to the bottom chords depending on design considerations. The slenderness ratio l/r of the bridging angle must not exceed Sizes of bridging angle for various joists centres Centres of joists (m) Standard bridging angle (mm) x 50 x x 60 x x 80 x x 00 x 8 Wind reversal Where construction loads are light the bottom chords should be checked for compression due to the wind reversal forces. Please contact Metsec Lattice Beam Technical Department for further advice. Knee bracing 28

30 Design examples and load tables Design examples and load tables Design examples Parallel beam - span/depth ratio As a guide, depths of roof beam, conform approximately to the following: Approximate depth = span/20 i.e. 0m span/20 = 500mm deep Design example Joist span Joist spacing Roof loading: 0,000mm 4,500mm Decking and insulation 0.20kN/m 2 Ceiling and services 0.30kN/m 2 Allow S.Wt steelwork 0.0kN/m 2 Dead load 0.60kN/m 2 x.4 = 0.84kN/m 2 Imposed load 0.60kN/m 2 x.6 = 0.96kN/m 2 Total load.20kn/m 2.80kN/m 2 Total load requirement =.80 x 4.5 = 8.0kN/m Imposed load requirements = 0.6 x 4.5 = 2.70kN/m Refer to load tables. Use Metsec lattice beams ref: MD50 Total load capacity 8.83kN/m (>8.0) Imposed load capacity 3.83kN/m (>2.70) Designation The designation of beam configurations and depths is given by a simple letter and number code, as follows: Chord Depth at Configuration Pitch type shallow end or radius MB ML (cm) T (tapered) Gradient ( o ) TR (pitched) Radius (m) PP (parallel pitched) I (inverted) Example MD 50 CT (curved truss) CB (curved beam) Thus MD50 comprises MD type chord sections with an overall beam depth of 500mm without pitch or taper. Example 2 MJ 60 TRW 0 0 Thus MJ60TRW(0 0 ) comprises MJ type chord sections with an overall truss depth at the shallow end of 600mm rising to a central ridge with a Warren type web pattern and a 0 0 slope. Important The lighter the beam, the more cost effective the solution. Stone Road, West Midlands 29

31 Design examples and load tables Design examples and load tables Typical truss options N type truss This is the most economical type of joist or truss when considering gravity loading only and where stress reversals are insignificant - i.e. longer diagonal members are in tension. Warren type truss with vertical posts Additional members are introduced to the basic warren type joist or truss to support loads which do not occur at node positions. Warren type truss May be preferred in having a better appearance than the N type joist or truss. Diagonals are alternatively struts and ties. Typical tapered truss options This results in a frame less susceptible to deflection than the N type. Summerhill Primary School, West Midlands 30

32 Design examples and load tables Design examples and load tables Lattice beam, in steel frame construction Lattice beam The Metsec lattice beam can provide a very attractive, lightweight, economical solution when used as a main support to the roof structure, being able to meet short, medium or long span requirements. Optional bottom tie Knee brace as required The beam can be provided with fully fixed end connections determined by simple frame analysis if required. Alternatively, they can be simply supported to carry vertical applied dead and imposed loads and fixed for horizontal wind as a common design assumption. Purlins The most economic section used for supporting the roof cladding is a cold rolled purlin. Metsec cold rolled Z-section purlins provide adequate lateral restraint to the top (compression) chord of the lattice beams. Bracing The longitudinal tensile forces in the Metsec Z-section purlins resulting from lateral restraint to the lattice beams are transmitted to the diagonal rafter bracing system provided at each end of the building. In addition to providing stability to the lattice beams, bracing also resists wind loading at the gable ends (i.e. gable posts propped at bracing node points) and acts as stability bracing during erection. Metsec eaves beam Vertical brace Vertical brace Gable posts Vertical brace Vertical brace Metsec lattice beam Metsec lattice beam Metsec lattice beam Metsec Z purlins Metsec lattice beam Metsec lattice beam Metsec lattice beam For longer buildings additional bracing may be required to intermediate bays. C L Ridge Cleader rail Vertical bracing as shown on the roof plan ensures that all forces are transmitted to the foundations. 3

33 Design examples and load tables Design examples and load tables Services Load bearing walls Suspended ceiling Lattice truss in load bearing wall construction Lattice truss The Metsec lattice truss provides a lightweight, economic solution when used as the roof lid main support member on load bearing wall construction. The lattice form provides a more flexible service zone within the ceiling void. Large spans of up to 40m are easily accommodated. Metsec truss Metsec Z purlins Metsec truss Purlins Metsec cold rolled Z-section purlins are used as economic support to the roof cladding and provide adequate lateral restraint to the top (compression) chord of the lattice truss. Rafter bracing The longitudinal forces in the Metsec Z-section purlins resulting from lateral restraint to the lattice truss are transmitted to the diagonal rafter bracing system. Bottom tie bracing The wind loading on vertical spanning side walls is resisted by a horizontal bracing system utilising a steel or concrete ring beam at bottom chord (eaves) level. This ring beam may be returned on the gable ends to provide intermediate lateral support to the walls. Horizontal span of ring beam Longitudinal tie Metsec truss Metsec truss Longitudinal tie Eaves bracing The longitudinal ties also serve as lateral restraint members to the bottom chord of lattice truss in compression from wind uplift. Ring beam 32

34 Design examples and load tables Design examples and load tables Load tables - Parallel beams Joist Overall Typical node Ixx Self weight Span (m) type depth (mm) centres (mm) (cm 4 ) (kg/m) MB MB MB MD MB MD MG MB MD MG MB MD MG MJ MB MD MG MJ ML MB MD MG MJ ML MB MD MG MJ ML MB MD MG MJ ML MB MD MG MJ ML MD MG MJ ML MD MG MJ ML MG MJ ML Span (m) Standard camber (mm)

35 Design examples and load tables Design examples and load tables Span ( ) 26 m Notes on load tables. All loads are in kilo Newtons per metre Notes on load tables (kn/m), and are calculated in accordance with. All loads are in kilo Newtons per BS 5950-: 2000 and 5: 998. metre (kn/m),calculated in accordance 2. Figures with BS in black and type 5:998. are Ultimate total loads 2. per Figures metre. in black type are ultimate total 3. BS loads 5950-: per metre and 5: 998 recommends that Unfactored imposed load deflections are 3. BS 5950: 998 recommends that imposed limited to span/360 where applicable. load deflections are limited to span/360 Therefore safe working loads shown in red where applicable. Therefore safe working type are calculated with a deflection limit of loads shown in red type are calculated with span/360. a deflection limit of span/ By calculating Unfactored imposed loads and 4. By calculating Unfactored imposed loads and Ultimate total loads in kilo Newtons per linear ultimate total loads in kilo Newtons per linear metre (kn/m) and referring to the appropriate metre (kn/m) and referring to the appropriate table a suitable selection can be made by table a suitable selection can be made by satisfying both imposed load and total load satisfying both imposed load and total criteria. load criteria. 5. Tables are based on: 5. Tables are based on: 5. The top (compression) chord of the beam is 5. The top (compression) chord of the beam provided with adequate lateral restraints at is provided with adequate lateral restraints at spacings not greater than.8m. spacings not greater than.8m. 5.2 The load is uniformly distributed on the 5.2 The load is uniformly distributed on the full span. full span. 6. Roof beams are fabricated with an upward 6. Roof beams are fabricated with an upward camber. The approximate camber for various camber. The approximate camber for various spans is shown in the tables. spans is shown in the tables. Floor joists are supplied straight unless a Floor joists are supplied straight unless camber is specifically requested. camber is specifically requested. 7. When design requirements are for depths When design requirements are for depths greater than 2.0m, or when curved, pitched or greater than 2.0m, or when curved, pitched or tapered profiles are required, please refer to tapered profiles are required, please refer to LatticeSPEC design software or consult the LatticeSPEC design software or consult the Metsec Lattice Beam Technical Department. Metsec Lattice Beam Technical Department

36 Design examples and load tables Design examples and load tables Load tables - Parallel beams Joist Overall Typical node Ixx Self weight type depth (mm) centres (mm) (cm 4 ) (kg/m) MG MJ ML MG MJ ML MJ ML MJ ML MJ ML MJ ML MJ ML MJ ML MJ ML MJ ML Span (m) Standard camber (mm) Notes on load tables. All loads are in kilo Newtons per metre (kn/m), and are calculated in accordance with BS 5950-: 2000 and 5: Figures in black type are Ultimate total loads per metre. 3. BS 5950-: 2000 and 5: 998 recommends that Unfactored imposed load deflections are limited to span/360 where applicable. Therefore safe working loads shown in red type are calculated with a deflection limit of span/ Roof beams are fabricated with an upward camber. The approximate camber for various spans is shown in the tables. Floor joists are supplied straight unless a camber is specifically requested. 7. When design requirements are for depths greater than 2.0m, or when curved, pitched or tapered profiles are required, please refer to LatticeSPEC design software or consult the Metsec Lattice Beam Technical Department. 4. By calculating Unfactored imposed loads and Ultimate total loads in kilo Newtons per linear metre (kn/m) and referring to the appropriate table a suitable selection can be made by satisfying both imposed load and total load criteria. 5. Tables are based on: 5. The top (compression) chord of the beam is provided with adequate lateral restraints at spacings not greater than.8m. 5.2 The load is uniformly distributed on the full span. 35

37 Services and design software Services and design software Services and general notes Detailing service Working from Architects and Consulting Engineers drawings, Metsec s team of engineers and specialist 3D detailers will produce structural layouts and sections to assist the site team along with full fabrication drawings. Customer service Metsec are committed to providing the highest levels of customer satisfaction and ensure that our staff are trained to the highest possible levels in order to assist our customers at all stages of the design and installation process. Our sales teams in particular have a thorough knowledge of our products and should be able to resolve most of your questions quickly and professionally. Research and development Metsec operate a policy of continuous research and development reserving the rights to change the specification for products in this literature without prior notice. Company Registration Metsec Lattice Beams Ltd Registered Office: Units 0 & Rolls Royce Estate, Spring Road, Ettingshall, Wolverhampton, West Midlands WV4 6JX. Company Number: (England) Tividale High School, West Midlands. 36

38 Services and design software Services and design software Software Design software Metsec are pioneers when it comes to the provision of design software packages. Our first package for lattice design was produced in 989, since when we have been continually updating and improving the packages that we offer. Today, Metsec produce a number of stand-alone design software packages including LatticeSPEC for our complete range of lattice beam solutions. This package enables the quick and easy design of all types of lattice beams. It also includes an option to export the profile of the lattice with its end section in.dxf format, enabling specifiers to import direct to their working drawings and to quickly and efficiently complete their detailing. For a free copy of the latest LatticeSPEC software please contact MLB on or visit our website: xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx xxxxxx Designed and produced by Communication Design Partnership