LYSAGHT W-DEK. Design and Construction Manual. Structural steel decking system

Transcription

1 LYSAGHT W-DEK Structural steel decking system Design and Construction Manual ptimised to bring greater efficiency, speed of construction and economy. Exceptional spanning characteristics (up to 4.1m) reduces propping required. ne of the best coverage-per-weight of steel which makes it economical. has excellent concrete displacement characteristics which saves material costs.

2 Warranty BlueScope Lysaght has a number of comprehensive product warranties that cover not only the corrosion performance of the material but also the structural and serviceability performance of a wide range of products. BlueScope Lysaght can back their products with over 150 years experience and credibility. The LYSAGHT brand is widely recognised as setting the benchmark on quality products, and is trusted and respected by our customers and competitors nationwide. Disclaimer, warranties and limitation of liability This publication is intended to be an aid for professional engineers and is not a substitute for professional judgement. Terms and conditions of sale are available at local BlueScope Lysaght sales offices. Except to the extent to which liability may not lawfully be excluded or limited, BlueScope Steel Limited will not be under or incur any liability to you for any direct or indirect loss or damage (including, without limitation, consequential loss or damage such as loss of profit or anticipated profit, loss of use, damage to goodwill and loss due to delay) however caused (including, without limitation, breach of contract, negligence and/or breach of statute), which you may suffer or incur in connection with this publication. LYSAGHT, LYSAGHT W-DEK, and GALVASPAN are trademarks of BlueScope Steel Limited A.B.N The LYSAGHT range of products is exclusively made by BlueScope Steel Limited trading as BlueScope Lysaght. Copyright BlueScope Steel Limited March 10, 2009 Produced at BlueScope Lysaght Reseach and Development. 2

3 Contents Background Features and applications Spanning capacities Composite action Design efficiency Economical design for fire Quicker trouble free installation Technical support Specification and Design composite slabs section properties Sheeting Concrete Reinforcement Shear connectors Design methods Formwork design Deflection limit Formwork design load Design for strength Design for serviceability Formwork Tables Composite slab design General Application Crack control options Durability Design load Strength load combination Serviceability load combination Superimposed dead load Design for Strength in negative regions Negative bending Strength Shear strength Design for strength in positive regions Positive bending Strength Shear strength Design for fire General Design for insulation and integrity Design for structural adequacy Design loads Reinforcement for fire design Location of longitudinal reinforcement for fire design Design Tables Use of design tables Single span design tables Interior span design tables End spans design tables Construction Safety Installation Propping Laying Interlocking the sheets Securing the platform Installing on steel frames Fastening side lap joints Fitting accessories for edge form Sealing Items embedded in slabs Holes Inspection Cutting Reinforcement Transverse reinforcement Longitudinal reinforcement Trimmers Concrete Specification Concrete additives Preparation Construction joints Placing Curing When to remove props Finishing Soffit and edge form finishes Plastering Change in floor loadings Suspended ceilings & services Plasterboard Suspended ceiling Suspended services Composite beams Shear stud capacities References

4 Background LYSAGHT W-DEK is a new innovative profiled steel decking which brings greater economy and design freedom to building with composite concrete slabs. Our design engineers scoured the globe to find the best W - profiles in the world. After careful examination, our engineers incorporated the best aspects of each profile into new. The profile has been specifically developed for Australian high tensile steels - which makes one of the best performing W profiles in the world. is a profiled zinc-coated high tensile steel decking for use in the construction of composite floor slabs. It has exceptional composite performance no additional reinforcement is required in most applications. It can be used as formwork during construction and as a reinforcement system in composite slabs. Our increased understanding of composite slabs, together with testing in our NATA-accredited laboratory and leading Australian universities, has paid off with an optimised product, which provides significant cost savings for projects. has exceptional spanning characteristics and spans up to 4.1 metres, reducing the need for supporting structures. The built-in properties of high tensile steel are maximised in the design and fabrication of the deck profiles which result in products with high strength-to-weight ratio. is currently the most economical structural steel decking in Australia for typical applications because it provides widest cover per weight of steel. The profiled ribs are 78mm in height, resulting in having excellent concrete displacement characteristics and minimal propping requirements. This speeds up installation and makes the costs of delivery, erection and structural framing significantly lower than for other systems. Scope This manual provides information on the design of formwork, propping, composite slabs and design for fire and some information for composite beams. This manual is developed to the latest versions of the relevant Australian Standards and Eurocodes. Conditions of use This publication contains technical information on the following grades of : 0.75 mm thickness 1.00 mm thickness Additionally, software allows you to get quicker and more economical solutions with a range of options. Call Steel Direct on to obtain additional copies of the Design Manual and Software. Where we recommend use of third party materials, ensure you check the manufacturer's requirements. Diagrams are used to explain the requirements of a particular product. Adjacent construction elements of the building that would normally be required in that particular situation are not always shown. Accordingly aspects of a diagram not shown should not be interpreted as meaning these construction or design details are not required. You should check the relevant Codes associated with the construction or design. Warranties Our products are engineered to perform according to our specifications only if they are installed according to the recommendations in this manual and our publications. Naturally, if a published warranty is offered for the product, the warranty requires specifiers and installers to exercise due care in how the products are applied and installed and are subject to final use and proper installation. Owners need to maintain the finished work. 4

5 1. Features and Applications Contact Steel Direct for advice on the design of concrete frame buildings. Use on masonry buildings is acceptable if the requirements of Section 7 are satisfied. 1.1 Spanning Capacities has superior spanning capacities. 1.0 mm BMT can span up to 4.1 metres when used on steel framed construction. After careful examination, our engineers incorporated the best aspects of each profile into new developed specifically for high tensile steel. This resulted in a new innovative and optimised shape for, having flange stiffeners and deep embossments, which act as web stiffeners, to increase the load carrying capacity. Due to the large depth of the profile, an increase of the flexural rigidity reduces deflections. 1.2 Composite Action Generally speaking, a profiled steel sheet forms permanent and integral formwork for the concrete slab. Commonly, the ribs of the profiled sheeting are perpendicular to the centreline of the steel I-section which supports it. The stud shear connectors are welded through the thin steel sheeting into the top flange of the steel beam. This creates a shear connection in the longitudinal beam by way of the mechanical shear connectors, as well as in the direction transverse to the beam by the embossments in the profiled sheeting. It is this connection that allows a transfer for forces and gives composite members their unique behaviour. has exceptional composite performance and leads to no additional reinforcement requirement in most applications. 1.3 Design Efficiency The range of gauges available (0.75 mm and 1.0 mm) allows much closer matching of design requirements and deck performance. 1.2 mm BMT is not available in the design tables and software. However, a solution with 1.2 mm BMT is available subject to enquiry. 1.4 Design for Fire composite slabs can be designed for up to 4 hours of fire rating. Guide tables in our manual are developed for fire periods of 60 and 90 minutes. Where necessary, additional bottom fire reinforcement is given in these tables. Our software can be used if other fire periods are required. Negative fire reinforcement is an additional design option in our design software. 1.5 Quicker Trouble-Free Installation The installation of follows traditional methods for quick and easy installation. It is available in long lengths so large areas can be quickly and easily covered to form a safe working platform during construction. provides a cover width of 700 mm, which is the widest cover per weight of steel currently available in Australia. 1.6 Technical Support Contact Steel Direct on for access to our technical support services. BlueScope Lysaght Technology at Chester Hill, NSW, together with your local BlueScope Lysaght Technical Sales Representatives, can be called upon also to provide comprehensive information regarding the correct use of for engineers, architects and builders. 5

6 2. Specification and Design 2.1 LYSAGHT W-DEK composite slabs Concrete Bar reinforcement b Embossments Mesh reinforcement D y b LYSAGHT W-DEK d cb SHEETING ELASTIC CENTROID t bm (BMT) Cover width 700 Figure 2.1 LYSAGHT W-DEK profile dimension and reinforcement 78mm 700mm 713.6mm Figure 2.2 profile and dimensions 2.2 LYSAGHT W-DEK Section Properties LYSAGHT W-DEK 1.00 BMT 0.75 BMT Table 2.1 Thickness BMT mm Self Weight (kg/m 2 ) Full Cross-sectional area of W-DECK mm 2 / m A sh Effective second moment of area l 1 4 mm 4 / m x Notes: 1. Self weight is given for Z350 coating. 2. Effective second moment of area varies depending on span values in a table. Values are given for longest spans only. 6

7 2.3 Sheeting is rolled-formed from hot dipped, zinc-coated, high tensile steels in base metal thickness (BMT) of 1.0 and 0.75 mm. 1.2 mm BMT is not available in the design tables and software. However, the solution using 1.2 mm BMT is available subject to enquiry. The steel conforms to: The coating is Z350 (350 g/m 2 minimum coating mass) or Z450 (450 g/m 2 minimum coating mass) is available subject to enquiry. Embossments on the top of flanges and web embossing provide the mechanical connection between the steel and concrete. 2.4 Concrete All tables have been developed for the 32 MPa grade of concrete with normal density of 2400 kg/m 3 (wet density). Other concrete grades are available in the software. 2.5 Reinforcement effects, as flexural negative reinforcement over supports and in some instances for fire engineering purposes and as bottom tensile reinforcement. It shall comply with the requirements of AS/NZS 4671:2001. the software. D500N is used only in the tables. bars for negative and fire reinforcement in addition to 500L shrinkage mesh. 2.6 Shear Connectors Extensive testing has been conducted in our NATA-registered lab and the University of Western Sydney. Shear stud capacities are available for secondary and primary composite beams. Those capacities can be achieved using conventional reinforcement in secondary beams and specific reinforcement developed by One Steel/University of Western Sydney in primary beams. For more information refer to Section 8 of this Manual: Composite Beams. 2.7 Design Methods There are a number of ways you can design concrete slabs using : Eurocodes and data from this manual. design software. This is also likely to produce a more economical design. However, if in doubt you should get advice from a specialist where required. 7

8 3. Formwork Design The formwork shall be designed in accordance to AS and AS capacities and stiffness have been derived from tests conducted at our NATA-accredited laboratory at BlueScope Lysaght Technology, Chester Hill, NSW. Our design tables can be used to detail acting as a structural formwork, provided the following conditions are satisfied: minimum bearing of 50 mm at the ends of the sheets, 100 mm minimum bearing length for interior supports. or intermediate splicing or jointing longitudinally. shall be restrained. sheeting ends shall be securely fixed at all permanent and temporary supports to the supporting structure l /L s ) of any two adjacent spans does not exceed 1.2 (i.e. L l /L s 1.2). during the construction phase can be ignored in design. Outline of concrete 50mm minimum Bearing on LYSAGHT W-DEK (Not less than100 mm where sheeting is continuous.) Equal sheeting spans L' 50mm minimum End support Temporary props LYSAGHT W-DEK Interior support Temporary props Interior support Slab span L Slab span L Interior support Figure 3.1 formwork 8

9 3.1 Deflection Limits AS Formwork for concrete, defines five classes of surface finish (numbered 1 to 5) covering a broad range of applications and AS We recommend a deflection limit of span/240 for the design of composite slabs in which good general alignment is required, so that the soffit appears straight when viewed as a whole. We consider span/240 to be suitable for a Class-3 and 4 surface finish and, in many situations, Class 2. Where alignment affects the thickness of applied finishes (for example vermiculite), you may consider a smaller limit of span/270 to be more suitable. We consider span/130 to be a reasonable maximum deflection limit appropriate for profile steel sheeting in situations where visual quality is not significant (Class 5). 3.2 Formwork Design Loads must be designed as formwork for two stages of construction according to AS and AS Stage I Prior to the placement of the concrete: concrete, When a live load due to stacked materials can be adequately controlled on the site at less than 4 kpa, the reduced design live load must be clearly indicated on the formwork documentation. (1kPa in tables from Section 3.3) Stage II During placement of the concrete up until the concrete has set (until fcm reaches 15-MPa and concrete is able to act flexurally to support additional loads such as stacked materials). NOTE: No loads from stacked materials are allowed until the concrete has set. formwork span only is loaded - with live loads, loads due to stacked materials and wet concrete. The has sufficient capacity for a concentrated point load of 2.0 kn for all spans and BMT. It is not necessary to perform formwork capacity checks for concentrated loads. 9

10 3.2.1 Design For Strength Design bending capacities The positive bending moment should be calculated using partial plastic theory. Negative moments over supports should not exceed the values given in Table 3.1. If the negative bending moment over the support obtained from linear elastic analysis exceeds the design negative bending capacity - negative moments shall be redistributed into positive area such as negative moment does not exceed value given in the tables. Bending moment in positive areas shall not exceed design moment capacity given in Table 3.1. Table 3.1 W-DEK moment capacities Design positive Design negative Capacity Capacity t bm u.sh (kn/m u.sh (kn/m Minimum value of: 3.2 (i) 6.61 (ii) L l where L l is in metres (distance between centres of permanent or temporary supports) Shear (web crippling) capacity of end support Interior supports shall not be checked for shear. The design shear capacity ( Vu,sh) for end bearing length of 50 mm or more, is : ( Vu,sh) = 25 kn/m (0.75 BMT) ( Vu,sh) = 38 kn/m (1.0 BMT) Design For Serviceability The maximum vertical deflection ( ), at completion of the concrete placement in all spans, is calculated using: d ef is calculated as follows: For 0.75 BMT I ef = Minimum of mm 4 or Maximum (L l 4 For 1.00 BMT I ef = Minimum ( L l 4 where L l is in mm. Table 3.2 Values of coefficient kd for calculation of (The maximum vertical deflection always occurs in the end span for these conditions.) 10

11 3.3 Formwork tables Formwork table 1.00 BMT No props Slab thickness, mm Single span Two spans Three or more spans prop Slab thickness, mm Single span Two spans Three or more spans Formwork table 0.75 BMT No props Slab thickness, mm Single span Two spans Three or more spans prop Slab thickness, mm Single span Two spans Three or more spans NOTES: 1. Continuous maximum spans are limited as given in composite slab tables for interior spans and total 6000mm limit. 2. Maximum formwork spans are based on L l /240 deflection limit and ratio of two adjacent spans equal 1:1. 3. Use software to get longer spans with L l /130 deflection limit and wider supports. 4. 1kPa Live Load due to stacked materials is used. 11

12 4. Composite Slab Design 4.1 General This chapter discusses the parameters upon which our design tables and software are based. Solutions to your design problems may be obtained by direct reference to either our design software, or our design tables in this Manual. Design data about composite performance of slabs with have been obtained from full scale slab tests conducted at the University of Newcastle. 4.2 Application Our design tables and software can be used to design composite slabs with provided the following conditions are satisfied: is in the range 25 MPa to 40 ƒ c MPa (as specified in AS ). The concrete density c may be for normal weight concrete, taken as c 2400kg/m 3. AS , Section 19. have a minimum bearing of 50 mm at the ends of the sheets, and 100 mm at intermediate supports over which sheeting is continuous. L 1 ) to the shorter slab span ( L s ) of any two adjacent spans does not exceed 1.2, that is L 1 /L s 1.2. uniformly-distributed and static in nature. vertical loads applied to the slab. profiles can be used in conjunction with this manual. High values of u,rd responsible for composite performance can only be achieved due to advanced features of. Refer to Table 4.1 for longitudinal shear resistance values. steel must be in accordance with AS , Clause 19.2, and the design yield stress, ( ƒ sy ), must be taken from AS , Table 6.2.1, for the appropriate type and grade of reinforcement, and manufacturers data. accordance with AS , Clause must not be spliced, lapped or joined longitudinally in any way. of the slab. AS , Clause 4.2.3, composite action must be assumed to exist between the steel sheeting and the concrete once the concrete in the slab has attained a compressive strength of 15 MPa, that is 15 MPa. Prior to the development of ƒ cj composite action during construction, potential damage to the shear allowed. regions shall be arranged in accordance with the Figures 4.1 and 4.2. Refer to AS , clause for more information on detailing of tensile reinforcement in one way slab. 12

13 4.3 Crack Control options Tables and software are developed to the latest recommendations of AS , Clause regarding flexural crack control. Our design tables for continuous spans assume full crack control. The software allows full and relaxed crack control. f s in the reinforcement and the design crack width a smaller bar diameter may result in less reinforcement being necessary. AS , Clause 9.4. Wall Wall Negative reinforcement 0.3Ln minimum 100mm 0.3Ln Cover Concrete slab 0.3L n Minimum 50mm LYSAGHT W-DEK Minimum 70mm Wall Wall Ln Ln Restraint at end support by mass of wall L (span) Continuous over interior support L (span) Little or no restraint at end support Figure 4.1 Pattern 1 for conventional reinforcement Wall Wall 0.3L n 0.3L n Cover Concrete slab 0.3L n LYSAGHT W-DEK 1/3 of negative reinforcement Wall Wall L n L n Restraint at end support by mass of wall L (span) Continuous over interior support L (span) Little or no restraint at end support Figure 4.2 Pattern 2 for conventional reinforcement when imposed load exceeds twice the dead load 13

14 4.4 Durability The exposure classification relevant to the design of slabs are A1, A2, B1 and B2 as defined in AS , Clause 4.3. The minimum concrete cover (c) to reinforcing steel, measured from the slab top face, must comply with AS , Table Design Loads Strength load Combinations For strength calculations, design loads for both propped and unpropped construction must be based on the following load combinations. Pattern loading shall be considered according to AS Clause As per AS G G G 15. Q c sh sup and for bending (composite) and shear capacity in positive (with top outer fibre of concrete in compression) areas. (as per pren ) 1.35 Gc Gsh Gsup 15. Q where G c G sh = G sup = superimposed dead load (partitions, floor tiles, etc.) Q = live load Serviceability Load Combinations Deflections due to loading applied to the composite slab should be calculated using linear elastic analysis in accordance with AS , Clause 3.4. and Note that the live load (Q) is applied after the removal of any temporary props and after the addition of any deflectionsensitive finishes. The loading pattern of vertical load should be considered in the analysis as per AS , Clause for short term loads. Loads for crack control shall be in accordance AS Clause Superimposed Dead Load The maximum superimposed dead load assumed in our design tables is 1.0 kpa. Use design software for other loads. 14

15 Table 4.1 LYSAGHT W-DEK Longitudinal shear resistance BMT u,rd (kpa) Design for Strength in Negative Regions Negative Bending Strength For the bending strength design in negative moment regions, the presence of the sheeting in the slab is ignored and the slab shall be designed allowing for 50% void area between ribs. For this purpose, use the provisions of AS , Section 9. The minimum bending strength requirement of AS , Clause 9.1 must be satisfied Shear Strength Negative moment regions must be designed for shear strength, to satisfy AS , Section 9. The negative moment region of composite slab shall be calculated allowing for voids between ribs which are 50% of cross sectional area within decking profile. 4.7 Design for Strength in Positive Regions Positive Bending Strength Positive-moment regions are designed for bending strength such that at every cross-section the design positive moment capacity is not less than the design positive bending moment capacity. Positive bending capacity shall be calculated as per pren Clause Partial shear connection theory shall be employed using values of u,rd in Table Shear Strength The positive shear capacity can be calculated as per Eurocode 2 Clause

16 5. Design for Fire 5.1 General The composite slabs shall be designed for fire conditions in accordance to AS The entire soffit of slab is assumed to be exposed to fire over both positive and negative moments regions. Temperature distribution through a cross section of a composite slab subject to fire is affected by the geometry of sheeting profile. Reduction factors are applied to allow for the adverse effect of elevated temperatures on the mechanical properties of concrete and steel. Values of these reduction factors shall be derived from the relationships given in AS , Clause 5.9. Our tables may be used to detail composite slabs when the soffit is exposed to fire provided the following conditions are satisfied: of the sheeting ribs for both room temperature and fire conditions. temperature conditions in accordance to this manual. nature. penetrating, embedded or encased services) to provide the appropriate fire resistance period. Alternatively the local provision of suitable protection (such as fire spray material) will be necessary. b= 140mm as per Figure 5.1 and 5.2 designates zone where fire and negative reinforcement shall be placed. 5.2 Design for Insulation and Integrity Minimum required overall depth (D) of slabs for insulation and integrity for various fire resistance periods is given in Table 5.1. These values are derived from test results. Table 5.1 Minimum overall depth (D) of LYSAGHT W-DEK slabs for insulation and integrity Fire Resistance Period (Minutes) Depth (D) mm Design for Structural Adequacy Design Loads Use AS Clause 2.5 together with Design load for fire Wf = 1.1G + l Q 16

17 5.4 Reinforcement for Fire Design The arrangement of reinforcement for fire design is shown in Figure 5.1. Fire reinforcement may be necessary, in addition to mesh and negative reinforcement required by our tables for composite slab design. the plastic hinges. - st,f for Fire detail 1 is in a single top layer at a depth of d ct below the slab top face (refer to figure 5.1). This detail is applicable to continuous slabs only + st,f for Fire detail 2 is in a single bottom layer at a distance of y b above the slab soffit (refer to Figure 5.1). This detail is applicable to both continuous and simple spans. + is designated A st,f in our tables (D500 N with bar diameter = 12 mm or less). st- ) and the additional fire reinforcement + - (A st,f or A st,f as applicable), must be located as shown in Figure 5.1 & 5.2. both options. A st, transverse A st.f A st Concrete x b x b d ct D LYSAGHT W-DEK Mesh (longitudinal - wires not shown) Concrete A st A st.f LYSAGHT W-DEK 0.3 L n L n L Fire detail 1 A st, transverse A st A st.f + A st + Concrete x b x b LYSAGHT W-DEK yb Mesh (longitudinal - wires not shown) D Concrete A st - A st.f + LYSAGHT W-DEK 0.3 L n Figure 5.1 Details of reinforcement for fire design Fire detail 2 L n L 17

18 5.5 Location of Longitudinal Reinforcement for Fire Design The longitudinal bars which make up A st.f +, A - st.f or A - should be located st within the zone shown in Figure 5.2. x b = 140mm y b = varies depending on the diameter of the supporting bar Transverse supporting bars (shrinkage mesh) Concrete A st. - (A st.f - ) x b x b LYSAGHT W-DEK y b A st.f + Permissible zone for longitudinal fire reinforcement A st.f +, A st.f - and A - st Fig. 5.2 Permissible zone for location of longitudinal fire reinforcement for Fire Detail 1 & 2. Negative reinforcement A - may be placed anywhere outside permissible st zone (See fig. 5.2) if design for fire is not required. 18

19 KEY - Single Spans Bottom reinforcement required for fire resistance of 60 minutes (mm 2 /m) KEY - Continuous Spans Top tensile (negative) reinforcements over supports (mm 2 /m) Fire reinforcement required for fire resistance of 90 minutes (mm 2 /m) Fire reinforcement required for fire resistance of 90 minutes (mm 2 /m) Fire reinforcement required for fire resistance of 60 minutes (mm 2 /m) Notes: 1. Areas without cells mean that a design solution is not possible. 2. Single spans do not require top tensile reinforcement, relevant cells are not shown. 3. All spans are centre to centre. 4. A dash (-) means no fire reinforcement is necessary. 5. N/A means a design solution with this particular fire rating is not possible. 6. Top tensile/negative reinforcement is additional to shrinkage mesh area Table 6.1 Shrinkage mesh used with tables. Depth Mesh 130 SL SL SL SL SL SL SL SL82 6. Design Tables 6.1 Use of Design Tables The design parameters specific for each table are given on the top of tables: The rest of parameters are common for all tables and listed below: 1 c = 32MPa. 3. W used as a structural deck with thickness 0.75 or 1.0mm BMT incremental deflection. mesh specified in Table 6.1. If negative fire reinforcement is required, at least one bar per rib should be placed. Smaller bar diameter may result in less negative and fire reinforcement. 19

20 6.2 Single Spans Single Spans 130 mm slab Span Characteristic Imposed Load Qk (kpa) N/A 70 N/A 70 N/A 80 N/A 90 N/A 100 N/A 130 N/A 150 N/A N/A 90 N/A 100 N/A 110 N/A 120 N/A 140 N/A 170 N/A 210 N/A N/A 130 N/A 130 N/A 140 N/A 160 N/A 180 N/A 220 N/A 260 N/A N/A 160 N/A 170 N/A 180 N/A 200 N/A 220 N/A 280 N/A 330 N/A N/A 200 N/A 210 N/A 230 N/A 250 N/A 280 N/A 340 N/A N/A 250 N/A 260 N/A 270 N/A 300 N/A 330 N/A N/A 290 N/A 310 N/A 330 N/A 360 N/A N/A 350 N/A 370 N/A 390 N/A N/A 410 N/A Single Spans 135mm slab Characteristic Imposed Load Qk (kpa) Span (mm) N/A 80 N/A 90 N/A 90 N/A 100 N/A 120 N/A 150 N/A 180 N/A N/A 110 N/A 120 N/A 120 N/A 140 N/A 150 N/A 190 N/A 230 N/A N/A 140 N/A 150 N/A 160 N/A 180 N/A 200 N/A 240 N/A 290 N/A N/A 180 N/A 190 N/A 200 N/A 220 N/A 240 N/A 300 N/A N/A 220 N/A 230 N/A 240 N/A 270 N/A 290 N/A N/A 260 N/A 270 N/A 290 N/A 320 N/A 350 N/A N/A 310 N/A 320 N/A 340 N/A N/A 360 N/A 380 N/A N/A Single Spans 140mm slab Span Characteristic Imposed Load Qk (kpa) N/A 100 N/A 100 N/A 110 N/A 120 N/A 140 N/A 170 N/A 200 N/A N/A 130 N/A 130 N/A 140 N/A 160 N/A 170 N/A 210 N/A 250 N/A N/A 160 N/A 170 N/A 180 N/A 200 N/A 210 N/A 260 N/A 310 N/A N/A 190 N/A 200 N/A 220 N/A 240 N/A 260 N/A 320 N/A N/A 230 N/A 240 N/A 260 N/A 280 N/A 310 N/A N/A 270 N/A 290 N/A 300 N/A 330 N/A N/A 320 N/A 340 N/A 350 N/A N/A 370 N/A Single Spans 145 mm slab Span Characteristic Imposed Load Qk (kpa)

21 Single Spans 150 mm slab Characteristic Imposed Load Qk (kpa) Span Single Spans 160 mm slab Span Characteristic Imposed Load Qk (kpa) Single Spans 175 mm slab Span Characteristic Imposed Load Qk (kpa) Single Spans 200 mm slab Span Characteristic Imposed Load Qk (kpa)

22 6.3 Interior Spans Interior Spans 130 mm slab Span Characteristic Imposed Load Qk (kpa) N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A 10 N/A - N/A - N/A - N/A - N/A N/A 30 N/A 40 N/A - N/A - N/A - N/A - N/A 10 N/A N/A 70 N/A 50 N/A - N/A - N/A - N/A 10 N/A N/A 50 N/A 20 N/A - N/A 10 N/A 10 N/A 20 N/A N/A 20 N/A 10 N/A 10 N/A 10 N/A 20 N/A N/A 10 N/A 10 N/A 20 N/A 20 N/A 30 N/A N/A 20 N/A 20 N/A 20 N/A 30 N/A 40 N/A N/A 30 N/A 30 N/A 30 N/A 40 N/A N/A 30 N/A 40 N/A 40 N/A N/A 40 N/A 50 N/A 50 N/A N/A 50 N/A 60 N/A N/A 60 N/A N/A 70 N/A N/A 5400 Interior Spans 135 mm slab Span Characteristic Imposed Load Qk (kpa) N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A 10 N/A - N/A - N/A - N/A - N/A 10 N/A N/A 30 N/A 10 N/A - N/A - N/A - N/A 10 N/A 20 N/A N/A 10 N/A 10 N/A - N/A - N/A - N/A 20 N/A N/A 10 N/A - N/A - N/A 10 N/A 10 N/A 20 N/A N/A - N/A 10 N/A 10 N/A 20 N/A 20 N/A N/A 10 N/A 10 N/A 20 N/A 20 N/A 30 N/A N/A 20 N/A 20 N/A 30 N/A 30 N/A N/A 30 N/A 30 N/A 30 N/A 40 N/A N/A 40 N/A 40 N/A 40 N/A N/A 40 N/A 50 N/A 50 N/A N/A 50 N/A 60 N/A N/A 60 N/A 70 N/A N/A

23 Interior Spans 140 mm slab Span Characteristic Imposed Load Qk (kpa) N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A - N/A N/A - N/A - N/A - N/A - N/A - N/A - N/A 10 N/A N/A 10 N/A - N/A - N/A - N/A - N/A 10 N/A N/A - N/A - N/A - N/A - N/A 10 N/A 20 N/A N/A - N/A - N/A 10 N/A 10 N/A 20 N/A N/A 10 N/A 10 N/A 10 N/A 20 N/A 20 N/A N/A 10 N/A 20 N/A 20 N/A 30 N/A 30 N/A N/A 20 N/A 20 N/A 30 N/A 30 N/A N/A 30 N/A 30 N/A 40 N/A 40 N/A N/A 40 N/A 40 N/A 40 N/A N/A 50 N/A 50 N/A 50 N/A N/A 50 N/A 60 N/A N/A 60 N/A N/A 5600 Interior Spans 145 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A N/A N/A N/A

24 Interior Spans 150 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A N/A N/A N/A Interior Spans 160 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A N/A N/A N/A

25 Interior Spans 175 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A N/A N/A Interior Spans 200 mm slab Span Characteristic Imposed Load Qk (kpa) N/A

26 6.4 End Spans End Spans 130 mm slab Span Characteristic Imposed Load Qk (kpa) N/A - N/A - N/A - N/A - N/A 10 N/A 30 N/A 30 N/A N/A 10 N/A 10 N/A 10 N/A 20 N/A 30 N/A 40 N/A 50 N/A N/A 30 N/A 30 N/A 40 N/A 50 N/A 60 N/A 60 N/A 80 N/A N/A 60 N/A 60 N/A 70 N/A 70 N/A 60 N/A 80 N/A 110 N/A N/A 90 N/A 100 N/A 100 N/A 80 N/A 80 N/A 110 N/A 140 N/A N/A 110 N/A 110 N/A 100 N/A 90 N/A 110 N/A 140 N/A 170 N/A N/A 130 N/A 120 N/A 100 N/A 120 N/A 130 N/A 170 N/A N/A 140 N/A 120 N/A 130 N/A 140 N/A 160 N/A 210 N/A N/A 150 N/A 150 N/A 150 N/A 170 N/A 190 N/A N/A 180 N/A 170 N/A 180 N/A 210 N/A 230 N/A N/A 200 N/A 200 N/A 210 N/A 240 N/A N/A 220 N/A 230 N/A 250 N/A N/A 250 N/A N/A End Spans 135 mm slab Span Characteristic Imposed Load Qk (kpa) N/A - N/A - N/A 10 N/A 10 N/A 20 N/A 30 N/A 40 N/A N/A 10 N/A 20 N/A 20 N/A 30 N/A 50 N/A 50 N/A 60 N/A N/A 40 N/A 40 N/A 50 N/A 60 N/A 50 N/A 70 N/A 90 N/A N/A 60 N/A 70 N/A 80 N/A 60 N/A 70 N/A 90 N/A 120 N/A N/A 90 N/A 90 N/A 80 N/A 80 N/A 90 N/A 120 N/A 150 N/A N/A 100 N/A 100 N/A 90 N/A 100 N/A 110 N/A 140 N/A N/A 110 N/A 100 N/A 110 N/A 120 N/A 140 N/A 180 N/A N/A 120 N/A 120 N/A 130 N/A 150 N/A 170 N/A N/A 150 N/A 150 N/A 160 N/A 180 N/A 200 N/A N/A 170 N/A 170 N/A 180 N/A 210 N/A N/A 190 N/A 200 N/A 210 N/A N/A 220 N/A 230 N/A N/A 250 N/A 26

27 End Spans 140 mm slab Span Characteristic Imposed Load Qk (kpa) N/A 10 N/A 10 N/A 10 N/A 20 N/A 30 N/A 40 N/A 50 N/A N/A 20 N/A 30 N/A 30 N/A 50 N/A 40 N/A 60 N/A 80 N/A N/A 50 N/A 50 N/A 60 N/A 50 N/A 60 N/A 80 N/A 100 N/A N/A 70 N/A 70 N/A 70 N/A 70 N/A 80 N/A 100 N/A 130 N/A N/A 80 N/A 80 N/A 80 N/A 90 N/A 100 N/A 130 N/A 150 N/A N/A 100 N/A 90 N/A 100 N/A 110 N/A 120 N/A 150 N/A N/A 100 N/A 110 N/A 120 N/A 130 N/A 150 N/A 180 N/A N/A 120 N/A 130 N/A 140 N/A 150 N/A 170 N/A N/A 140 N/A 150 N/A 160 N/A 180 N/A 200 N/A N/A 170 N/A 180 N/A 190 N/A 210 N/A N/A 190 N/A 200 N/A 220 N/A N/A 220 N/A 230 N/A N/A End Spans 145 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A

28 End Spans 150 mm slab Span Characteristic Imposed Load Qk (kpa) N/A N/A End Spans 160 mm slab Span Characteristic Imposed Load Qk (kpa)

29 End Spans 175 mm slab Span Characteristic Imposed Load Qk (kpa) N/A End Spans 200 mm slab Span Characteristic Imposed Load Qk (kpa)

30 7. Construction 7.1 Safety is available in long lengths, so large areas can be quickly and easily covered to form a safe working platform during construction. One level of formwork gives immediate protection from the weather, and safety to people working on the floor below. The minimal propping requirements provide a relatively open area to the floor below. It is common sense to work safely, protecting yourself and work mates as personal protection of eyes and skin from sunburn, and hearing from noise. For personal safety, and to protect the surface finish of, wear clean dry gloves. Don t slide sheets over rough surfaces or over each other. Always carry tools, don t drag them. Occupational health and safety laws enforce safe working conditions in most locations. Local laws may require you to have fall protection which includes safety mesh, personal harnesses and perimeter guard rails where they are appropriate. We recommend that you adhere strictly to all laws that apply to your State. is capable of withstanding temporary construction loads including the mass of workmen, equipment and materials as specified in Section 3.0 of this manual. However, it is good construction practice to ensure protection from concentrated loads, such as barrows, by use of some means such as planks and/or boards. 7.2 Installation is delivered in strapped bundles. If not required for immediate use stack sheets or bundles neatly and clear of the ground, on a slight slope to allow drainage of water. If left in the open, protect with waterproof covers. Cover Concrete slab Cover p Figure 7.1 Typical layout LYSAGHT W-DEK Bearing of LYSAGHT W-DEK (Not less than 50 mm at end of sheets) Props where required Bearing of LYSAGHT W-DEK (Not less than 100 mm where sheeting is continuous) Slab span (Interior span) Props where required Slab span End span) 30

31 7.2.1 Propping It is a common practice to specify unpropped formwork, however, depending on the span of a slab, temporary propping may be needed between the slab supports to prevent excessive deflections or collapse of the formwork. formwork is normally placed directly on prepared propping. Props must stay in place during the laying of formwork, the placement of the concrete, and until the concrete has reached the strength of 15 MPa. Propping generally consists of substantial timber or steel bearers supported by vertical props. The bearers must be continuous across the full width of LYSAGHT W-DEK formwork. Propping must be adequate to support construction loads and the mass of wet concrete. Maximum propped and unpropped spans are given in Section Laying must be laid with the sheeting ribs aligned in the direction of the designed spans. Other details include the following: sheets continuously over each slab span without any intermediate splicing or jointing. sheets end to end. Centralise the joint at the slab supports. Where jointing material is required the sheets may be butted against the jointing material. sheets across their full width at the slab support lines and at the propping support lines. the minimum bearing is 50 mm for ends of sheets, and 100 mm for intermediate supports over which the sheeting is continuous Interlocking the Sheets Overlapping ribs of sheeting are interlocked. Place the female lap rib overlapping the male lap rib of the first sheet at an approximately 45º angle to the one previously laid, and then simply lower it down, through an arc (see Figure 7.2) until the laps engage. If sheets don t interlock neatly (perhaps due to some damage or distortion from site handling or construction practices) use screws to pull the laps together tightly (see Section 7.2.6, Fastening side-lap joints). Position LYSAGHT W-DEK sheet at a 45º angle. Interlock sheets by lowering female lap of sheet over male lap through an arc. Figure 7.2 Method of interlocking adjacent sheets 31

32 7.2.4 Securing the Platform Once laid, provides a stable working platform. shall be fixed to supporting structure at all permanent and temporary supports with screws or nails or equivalent. Where additional security is needed you can use: Take care if you use penetrating fasteners (such as screws and nails) because they can make removal of the props difficult, and perhaps result in damage to the Installing LYSAGHT W-DEK on Steel Frames may be installed directly on erected structural steel works. General fastening of LYSAGHT W-DEK The sheeting shall be fixed to the structural steel using spot welds, or fasteners such as self-drilling screws or equivalent. Place the fixings (fasteners and spot welds) in the flat areas of the pans adjacent to the ribs or between the flutes. The frequency of fixings depends on wind or seismic conditions and good building practice. However at least one fastener per pan shall be provided at all supports. Use one of the fixing systems as appropriate. with self-drilling screws or spot welds or equivalent. hexagon head screws or equivalent. hexagon head screws or equivalent. welded must be free of loose material and foreign matter. Where the LYSAGHT W-DEK soffit or the structural steel works has a prepainted surface, securing methods other than welding may be more appropriate. Take suitable safety precautions against fumes during welding zinc coated products. Fastening composite beams Stud welding through the sheet has been considered a suitable securing fixing by one of the methods mentioned above is necessary to secure the sheeting prior to the stud welding. Some relevant welding requirements are: scale, rust, moisture, paint, over spray, primer, sand, mud or other contamination that would prevent direct contact between the parent material and the sheets, special welding procedures 10-24x16mm hex. head self-drilling screw, midway between embossments. Figure 7.4 Fixing at a side lap Figure 7.3 Positions for fixing to steel framing Fixing at sheeting supports 32

33 7.2.6 Fastening Side lap joints If sheeting has been distorted in transport, storage or erection, side-lap joints may need fastening to maintain a stable platform during construction, to minimise concrete seepage during pouring, and to gain a good visual quality for exposed soffits (Figure 7.4) Fitting accessories for EDGE FORM EDGE FORM is a simple C-shaped section that simplifies the installation of most slabs. It is easily fastened to the sheeting, neatly retaining the concrete and providing a smooth top edge for quick and accurate screeding. We make it to suit any slab thickness. EDGE FORM is easily spliced and bent to form internal and external corners of any angle and must be fitted and fully fastened as the sheets are installed. There are various methods of forming corners and splices. Some of these methods are shown in Figures 7.5 and 7.6. Fasten EDGE FORM to the underside of unsupported panels every 350mm. The top flange of EDGE FORM must be tied to the ribs every 700mm with hoop iron 25mm x 1.0mm (Figures-7.7). Use x 16mm self-drilling screws. Fastening bottom flange of EDGE FORM LYSAGHT W-DEK EDGE FORM Fastening positions Fasten EDGE FORM to the underside of unsupported LYSAGHT W-DEK at 350 mm maximum centres. Fastening top flange of EDGE FORM Hoop iron EDGE FORM LYSAGHT W-DEK Hoop iron EDGE FORM Tie top flange of EDGE FORM, to LYSAGHT W-DEK ribs, with hoop iron, every 700 mm maximum. Figure 7.5 Typical fastening of EDGE FORM to 33

34 External corner 1. Notch top flange for the required angle 2. Cut 'V' in bottom flange 3. Bend corner of EDGE FORM to the required angle, overlapping bottom flanges. Internal corner 1. Cut top and bottom flanges square. 2. Bend EDGE FORM to required angle. 3. Fasten top flange, each side of corner, to LYSAGHT W-DEK rib, 100mm maximum from corner. Splicing two pieces 1. Cut-back top and bottom flanges of one EDGE FORM section approximately 200mm. 2. Cut slight taper on web. 3. Slide inside adjoining EDGE FORM, and fasten webs with at least 2 screws Figure 7.6 Fabrication of formwork is easy with EDGE FORM A galvanised section that creates a permanent formwork at the slab edges cut, mitred and screwed on site. Stock length: 6100 mm Brackets from hoop iron Figure 7.7 Fabrication accessories for Sealing Seepage of water or fine concrete slurry can be minimised by following common construction practices. Generally gaps are sealed with waterproof tape or by sandwiching contraction joint material between the abutting ends of sheet. If there is a sizeable gap you may have to support the waterproof tape. (Figure 7.8). 34 Figure 7.8 Use waterproof tape to seal joints in sheets and end capping to seal ends

35 7.2.9 Items Embedded in Slabs Included are pipes and conduits, sleeves, inserts, holding-down bolts, chairs and other supports, plastic strips for plasterboard attachment, contraction joint material and many more. Location of items within the slab (Figure 7.9) Minimise the quantity and size of holes through sheeting, by hanging services from the underside of. Top-face reinforcement Bottom-face reinforcement Zone for pipes laid across the ribs (between top and bottom reinforcement) Concrete Figure 7.9 Zones for location of items embedded in slabs Zones for pipes and other items laid parallel with the ribs LYSAGHT W-DEK Holes acts as longitudinal tensile reinforcement similarly to conventional bar or fabric reinforcement does in concrete slabs. Consequently, holes in sheets, to accommodate pipes and ducts, reduce the effective area of the steel sheeting and can adversely effect the performance of a slab. Some guidelines for holes are (Figure 7.10): distance of 15 mm from the rib gap. support of the slab less than one tenth of a clear span. Zone for holes through sheet in central pan Max. diameter 110 mm Minimum 0.1 Ln Zone for holes in continuous slabs Minimum 0.1 Ln 15 mm minimum Location of holes in sheet Figure 7.10 Zones for location of holes through. Location of holes relative to supports in continuous slabs Interior supports Ln 35

36 Inspection We recommend regular qualified inspection during the installation, to be sure that the sheeting is installed in accordance with this publication and good building practice Cutting It is easy to cut sheets to fit. Use a power saw fitted with an abrasive disc or metal cutting blade. Initially lay the sheet with its ribs down, cut through the pans and part-through the ribs, then turn over and finish by cutting the tops of the ribs. 7.3 Reinforcement sheeting acts as longitudinal tensile reinforcement. The condition of sheeting should be inspected before concrete is poured. Reinforcement in slabs carries and distributes the design loads and controls cracking. Reinforcement is generally described as transverse and longitudinal in relation to span, but other reinforcement required for trimming may be positioned in other orientations. Figure 7.11 shows a typical cross-section of a composite slab and associated terms. Reinforcement must be properly positioned, lapped where necessary to ensure continuity, and tied to prevent displacement during construction. Fixing of reinforcement shall be in accordance with AS Clause To ensure the specified minimum concrete cover, the uppermost layer of reinforcement must be positioned and tied to prevent displacement during construction. Where fabric is used in thin slabs, or where fabric is used to act as both longitudinal and transverse reinforcement, pay particular attention to the required minimum concrete cover and the required design reinforcement depth at the splices splice bars are a prudent addition. Always place chairs and spacers on pan areas. Depending upon the type of chair and its loading, it may be necessary to use plates under chairs to protect the, particularly where the soffit will be exposed. Transverse reinforcement may be used for spacing or supporting longitudinal reinforcement. Concrete cover Bar reinforcement Transverse wires of mesh Depth of composite slab LYSAGHT W-DEK sheeting Figure 7.11 Typical cross-section of a slab showing common terms For fire reinforcement requirements, see Figure 5.2. Mesh reinforcement (fabric) Transverse Reinforcement Transverse reinforcement is placed at right-angles to the ribs of. Deformed bar or fabric reinforcement may be used. In most applications the transverse reinforcement is for the control of cracks caused by shrinkage and temperature effects, and for locating longitudinal reinforcement To control flexural cracking in the top face of the slab, transverse reinforcement in the top-face may be required over walls or beams which run in the same direction as the sheets. For ease of construction, reinforcement for control of cracking due to shrinkage and temperature is usually fabric reinforcement. 36

37 7.3.2 Longitudinal Reinforcement Longitudinal reinforcement is positioned to carry design loads in the same direction as the ribs of. Deformed bar or fabric reinforcement may be used. Top-face longitudinal reinforcement is usually located over interior supports of the slab and extends into approximately a third of the adjoining spans. Bottom-face longitudinal reinforcement is located between supports of the slab but, depending upon the detailing over the interior supports, it may be continuous, lapped, or discontinuous. Bottom-face longitudinal reinforcement may be placed on top of or below transverse reinforcement. Location of top and bottom-face longitudinal reinforcement in elevated temperatures requires special design. (Figure-5.2) Trimmers Trimmers are used to distribute the design loads to the structural portion of the slab and/or to control cracking of the concrete at penetrations, fittings and re-entrant corners. Deformed bar or fabric reinforcement may be used. Trimmers are sometimes laid at angles other than along or across the span, and generally located between the top and bottom layers of transverse and longitudinal reinforcement. Trimmers are generally fixed with ties from the top and bottom layers of reinforcement. 7.4 Concrete Specification The concrete is to have the compressive strength as specified in the project documentation and the materials for the concrete and the concrete manufacture should conform to AS Concrete Additives Admixtures or concrete materials containing calcium chloride or other chloride salts must not be used. Chemical admixtures including plasticisers may be used if they comply with AS Clause Preparation Before concrete is placed, remove any accumulated debris, grease or any other substance to ensure a clean bond with the sheeting. Remove ponded rainwater Construction Joints It is accepted building practice to provide construction joints where a concrete pour is to be stopped. Such discontinuity may occur as a result of a planned or unplanned termination of a pour. A pour may be terminated at the end of a day s work, because of bad weather or equipment failure. Where unplanned construction joints are made, the design engineer must approve the position. In certain applications, the addition of water stops may be required, such as in roof and balcony slabs where protection from corrosion of reinforcement and sheeting is necessary. Construction joints transverse to the span of the sheeting are normally located at the mid-third of a slab span) and ideally over a line of propping. Locate longitudinal construction joints in the pan (Figure 7.12). It may be necessary to locate joints at permanent supports where sheeting terminates. This is necessary to control formwork deflections since formwork span tables are worked out for UDL loads. Form construction joints with a vertical face the easiest technique is to sandwich a continuous reinforcement between two boards. 37

38 Prior to recommencement of concreting, the construction joint must be prepared to receive the new concrete, and the preparation method will depend upon the age and condition of the old concrete. Generally, thorough cleaning is required to remove loose material, to roughen the surface and to expose the course aggregate. Form boards sandwiching continuous reinforcement. Lower board shaped to match LYSAGHT W-DEK profile Concrete It may be necessary to locate joints at LYSAGHT W-DEK permanent supports Prop where sheeting terminates to control formwork deflections. Transverse construction joint Form boards sandwiching continuous reinforcement. Concrete Figure 7.12 Typical construction joint Longitudinal construction joint Placing The requirements for the handling and placing of the concrete are covered in AS Clause The concrete is placed between construction joints in a continuous operation so that new concrete is placed against plastic concrete to produce a monolithic mass. If the pouring has to be discontinued for more than one hour, depending on the temperature, a construction joint may be required. Start pouring close to one end and spread concrete uniformly, preferably over two or more spans. It is good practice to avoid excessive heaping of concrete and heavy load concentrations. When concrete is transported by wheel barrows, the use of planks or boards is recommended. During pouring, the concrete should be thoroughly compacted, worked around ribs and reinforcement, and into corners of the by using a vibrating compacter. Ensure that the reinforcement remains correctly positioned so that the specified minimum concrete cover is achieved. Unformed concrete surfaces are screeded and finished to achieve the specified surface texture, cover to reinforcement, depths, falls or other surface detailing. Surfaces which will be exposed, such as and exposed soffits, should be cleaned of concrete spills while still wet, to reduce subsequent work. 38

39 7.4.6 Curing After placement, the concrete is cured by conventional methods, for example, by keeping the slab moist for at least seven days, by covering the surface with sand, building paper or polythene sheeting immediately after it has been moistened with a fine spray of water. Follow good building practice. Be particularly careful when curing in very hot or very cold weather. Until the concrete has cured, it is good practice to avoid concentrated loads such as barrows and passageways with heavy traffic When to Remove Props Various factors affect the earliest time when the props may be removed and a slab initially loaded. Methods of calculating times and other guides are given in AS , Clause Finishing Soffit and EDGE FORM Finishes For many applications, gives an attractive appearance to the underside (or soffit) of a composite slab, and will provide a satisfactory ceiling for example, in car parks, under-house storage and garages, industrial floors and the like. Similarly, will give a suitable edging. Additional finishes take minimal extra effort. Where the soffit is to be the ceiling, take care during construction to minimise propping marks (refer to Installation Propping), and to provide a uniform surface at the side-laps (refer to Installation Fastening Side-lap joints). Exposed surfaces of soffit and may need cleaning and/or preparation for any following finishes Plastering Finishes such as vermiculite plaster can be applied directly to the underside of with the open rib providing a positive key. With some products it may be necessary to treat the galvanised steel surface with an appropriate bonding agent prior to application. Plaster-based finishes can be trowelled smooth, or sprayed on to give a textured surface. They can also be coloured to suit interior design requirements Change of Floor Loadings Where a building is being refurbished, or there is a change of occupancy and floor use, you may need to increase the fire resistance of the composite slabs. This may be achieved by the addition of a suitable fire-protection material to the underside of the slabs. 39

40 7.6 Suspended Ceilings and Services Plasterboard A soffit may be covered with plasterboard by fixing to battens. Fixing to battens Steel ceiling battens can be fixed directly to the underside of the slab using powder-actuated fasteners. The plasterboard is then fixed to ceiling battens in the usual way (Figure-7.13). Concrete Batten Plaster board Figure 7.13 Fixing plasterboard to Suspended Ceiling Ceilings are suspended from hangers attached to eyelet pins power driven into the underside of the slab Suspended Services Services such as fire sprinkler systems, piping and ducting are easily suspended from slabs using traditional installation methods to support these services. 40

41 8. Composite Beams Research by BlueScope Lysaght Technology, University of Sydney and University of Western Sydney was conducted to determine the design parameters of composite beams with. Primary and secondary composite beams can be designed in accordance with AS provided the following design rules are followed: in the haunch in the primary composite beams. Refer to Figure 8.1. Contact Steel Direct for more information. secondary composite beams) shall be used. Refer to Figure 8.2. composite beams). at 300mm spacing on tops of ribs. beams provided minimum overhang is 600 mm, alternatively follow AS requirements Primary beams can be designed as continuous - pren or BS :1990 should be followed. 8.1 Shear Stud Capacities 120mm long shear studs (115mm after welding) with 19mm nominal shank diameter shall be used. Capacities of shear studs in primary beams with single rows of studs (see Figure 8.1) shall be determined without applying reduction factors. Contact Steel Direct for reinforcement options and capacity of studs when two rows of studs are necessary and capacity of shear studs in secondary beams. 41

42 19mm stud x 115mm high after welding (may be single studs as shown or pairs of 60-80mm transverse centres) Slab reinforcement Haunchmesh Handlebar when necessary 150mm 7.5mm Figure 8.1 Primary beams LYSAGHT W-DEK 9.5mm 240mm HAUNCHMESH - STRAIGHT Supported directly on top of LYSAGHT W-DEK and placed centrally in haunch. LYSAGHT W-DEK Haunch and studs not necessarily centred over steel beam (omitted for clarity). Bar reinforcement Staggered single shear studs Mesh reinforcement or equivalent Staggered pairs of studs Steel beam Alternate location of single studs Figure 8.2 Shear stud position in secondary beam (alternate location - single studs) 42

43 9. References Commentary Section 3.1 Code of practice for design of simple and continuous composite beams for buildings Part 1-1 General rules and Rules for buildings Part 1-2 General rules Structural fire design 43

44 Disclaimer, warranties and limitation of liability This publication is intended to be an aid for all trades and professionals involved with specifying and installing LYSAGHT products and not to be a substitute for professional judgement. Terms and conditions of sale available at local BlueScope Lysaght sales offices. Except to the extent to which liability may not lawfully be excluded or limited, BlueScope Steel Limited will not be under or incur any liability to you for any direct or indirect loss or damage (including, without limitation, consequential loss or damage such as loss of profit or anticipated profit, loss of use, damage to goodwill and loss due to delay) however caused (including, without limitation, breach of contract, negligence and/or breach of statute), which you may suffer or incur in connection with this publication. Copyright BlueScope Steel Limited 9 March, 2009 Information, brochures and your local distributor Please check the latest information which is always available at BLUESCOPE, LYSAGHT, LYSAGHT W-DEK, EDGE FORM, GALVASPAN & ZINCALUME are registered trademarks of BlueScope Steel Limited, ABN THE LYSAGHT range of products is exclusively made by BlueScope Steel Limited trading as BlueScope Lysaght. Printed by BMP 1M0309