REINFORCING PRODUCT CATALOGUE MESH PRODUCT CATALOGUE MESH JAN 2013 S&T025

Transcription

1 S&T025 JAN 2013 PRODUCT CATALOGUE MESH PRODUCT CATALOGUE MESH REINFORCING

2 INDEX Introduction 1 NZ Standards relating to Steel Wire Fabric 2 Sheet Sizes 3 & 4 Standard Meshes, Wire Size, Pitch, Mass and Volume 5 Lappages 6 Lap Examples 7 Lap Charts 8 Bar to Mesh Conversions 9 Conversion Chart 10 Mass per m2 for Wire Sizes 11 Area per Metre Width for Wire Sizes 12 Wire/Steel Charts 13 & 14 Mechanical Limitations of Fabrication 15

3 INTRODUCTION This Handbook has been produced for the Civil and Structural Engineering professions as an information resource on the nature of steels, welding processes and design criteria for welded fabric. It will also aid designers in assessing and calculating steel wire fabric options for specific constructional requirements. The standard listing of products, sizes, applications and additional related services available will also be relevant to the Construction Industry in general. Whilst every effort has been made to ensure the accuracy of any information, advice or recommendations it may offer, no liability or responsibility of any kind is accepted in this respect. 1

4 NEW ZEALAND STANDARDS The Standards Association of New Zealand controls the preparation and publishing of all Standard Specifications and Codes of Practice in New Zealand. The New Zealand Standards mentioned in this section, control the mechanical properties of the steel wire used for concrete reinforcement, the fabrication of the welded fabric and the methods of application in respect to concrete reinforcement. Further information can be obtained from: Standards Association of New Zealand, Private Bag Wellington NZ3421:1975 Specification for Hard Drawn Mild Steel Wire for Concrete Reinforcement The Standard requires the following tensile properties:- NOMINAL DIAMETER (mm) MINIMUM 0.2% PROOF TENSILE STRENGTH (MPa) STRESS (MPa) Maximum Minimum Up to and including Over NZ3422:1975 Specification for Welded Fabric of Drawn Steel Wire for Concrete Reinforcement This Standard requires a minimum average Weld Shear load Where the longitudinal wire diameter is in the range 11mm to 3.15mm and the longitudinal to transverse wire diameter differential does not exceed 3mm, the minimum average shear value in Newtons shall be not less than 240 multiplied by the cross-sectional area of the longitudinal wire in square millimetres, and dictates requirements of The distance between centres of two adjacent wires shall not vary by more than 7.5 percent from the exact pitch. If fabric is required to be cut to specific dimensions, the tolerance shall be as follows : 5 Metres and under +25mm Over 5 metres +0.5% NZS3101:2006 Code of Practice for The Design of Concrete Structures This Standard lays out the development length and lap-splice requirements for plain wire fabric and deformed wire fabric, and is the basis of any pertinent calculations or recommendations given in this Handbook. 2

5 SHEET SIZES Standard production sheet sizes have been designed to offer the user an economical unit for construction purposes. The Dimensions offered relate to NZ Standard lap requirements fabrication limitations and also to on-site handling practicalities. Sheets can be fabricated to specific dimensional requirements if quantities are sufficient to make production runs viable. However, the following are offered as stock product. The dimensions shown are overall sheet sizes and include the end and side overhangs. Standard HRC overhangs are nominally 20mm either side. The end overhang is nominally half the pitch (i.e. on a 66 Mesh the end overhang is = 75mm). 3

6 DEFORMED MESH 668 Equivalent: D dia deformed wire at 300 centres Overall size 2290 x 5100 Effective area after lapping 10.08m 2 Utilises double selvedge wires 665 Equivalent: D dia deformed wire at 300 centres Overall size 2400 x 6900 Effective area after lapping 13.86m 2 Utilises equal overhangs Deformed Meshes are designed to exactly match the traditional 66 meshes for strength while minimising wastage of materials in the lap area. The D numbers are taken from the nominal sectional area of steel per metre width presented by the welded wire fabric. 664 Equivalent: D dia deformed wire at 150 centres Overall size 2400 x 6900 Effective area after lapping 13.86m 2 Utilises asymmetric overhangs 663 Equivalent: D dia deformed wire at 150 centres Overall size 2400 x 6900 Effective area after lapping 13.86m 2 Utilises asymmetric overhangs 662 Equivalent: D dia deformed wire at 150 centres Overall size 2400 x 6900 Effective area after lapping 13.86m 2 Utilises asymmetric overhangs 661 Equivalent: D dia deformed wire at 150 centres Overall size 2400 x 6900 Effective area after lapping 13.86m 2 Utilises asymmetric overhangs 4

7 STANDARD SHEET SIZES HRC SHEET TYPE WIRE SIZE (mm) PITCH (mm) STEEL AREA per METRE WIDTH (mm 2 ) SHEET SIZE (mm x mm) NET COVER AFTER LAPPING (m 2 ) MASS per m 2 SHIPING VOLUME per 100m Ecomomy x Economy x Economy x Economy x Large x Large x Large x Large x Large x Large x Large x Large x Large x D Def x D Def x D Def x D Def x D Def x D Def x

8 LAPPAGES Lap-splice requirements for Welded Wire Mesh are set by the NZ Standards Association in NZS3101:2006 and are subject to a number of variables. The following charts have been calculated for the convenience of the user. It is believed that most design situations will be satisfied; however, no responsibility for design accuracy can be assumed and designers should refer back to NZS3101:2006 for substantiating calculations. The design assumptions made for these charts are listed below. Notice should be taken of the NZ Standards Association s differential of requirements for plain wire fabric and deformed wire fabric. Similar lap-splice requirements are not acceptable, and current sheet designs are tailored to suit NZ Standards requirements. For this reason, deformed wire mesh lappages are calculated as per deformed bar. Assumptions as listed are referenced in terms of NZS3101 Nomenclature. fy = 485 MPa Yield strength of steel F = 25 MPa Compressive strength of concrete Asr/Asp = 1.0 Ratio of steel required to steel provided C = 20mm + db/2 Concrete over The following charts list overall lap-splice requirements of Welded wire fabric in as much as they show the required overlap of mesh from the perimeter of the sheet. 6

9 LAP DIAGRAMS 7

10 LAPPING 8

11 LAPPAGES CONVERSIONS MESH COMMENTS SIDE LAP END D84 D147 D188 D212 D264 D295 84XP 147XP 2 Wires plus 50mm for encasement plus overhangs Overhangs to reach edge wire 2 Squares of double edge wires plus overhangs NOTE: If sheets are cut and overhang or edge wire detail is lost, laps must revert to: 2 Wires plus 50mm in the lap zone In some circumstances such as building slabs, reinforcing bar can be substituted with welded mesh. There are substantial savings in labour and time that can be gained by using welded mesh instead of tied re-bar. The quick reference conversion chart on page 10, makes allowance for the differences in design strengths of 500 grade and 300 grade re-bar and the 485 proof stress of hard drawn reinforcing wire. Eg: from the chart, 300 = 662 = D264 Which means 10 diameter 500 grade bar at 300mm centres can be substituted with 662 mesh or D264 construction mesh. 9

12 QUICK REFERENCE CONVERSION CHART 10

13 MASS PER SQUARE METRE FOR WIRES IN ONE DIRECTION AT VARIOUS SPACINGS DIA Kg PER LINEAL WIRE SPACINGS kgs 50mm 75mm 100mm 150mm 200mm 225mm 250mm 300mm ,

14 SECTIONAL AREA PER METRE WIDTH DIA SECTIONAL AREA mm sq WIRE SPACINGS mm sq 50mm 75mm 100mm 150mm 200mm 225mm 250mm 300mm

15 WIRE CHART DIAMETER mm NEAREST ISWG CROSS SECTIONAL AREA mm2 kg PER METRE METRES PER kg / / / / /

16 STEEL BAR CHART DIAMETER mm CROSS SECTIONAL AREA mm 2 MASS PER UNIT LENGTH kg/m LENGTH PER 1000kg

17 MECHANICAL LIMITATIONS Welded Wire Fabric is produced from a series of longitudinal and transverse steel wires, resistance welded at all intersections. The manufacturing process can be varied to accommodate various style changes and dimensions. (However, consideration should be given to the complexity of the change). The manufacturing variables are listed in the general order of time involved, starting with the most time consuming. (a) Longitudinal wire spacing (b) Width of sheet (c) Side and end overhangs (d) Transverse wire spacing (e) Transverse wire size (f) Longitudinal wire size (g) Length of sheet. The more difficult machine changes require greater quantities per item in order to offset the additional production time required. Generally, it is more economical to order a few basic sheet sizes and styles than to specify many variations in the sheet. The following maximum dimensions are given as a guide but may be subject to regional variations due to differences in plant. Maximum overall width 2700mm Maximum overall length 7000mm Maximum number of longitudinal wires 36 15

18 HURRICANE REINFORCING MESH TESTING New Zealand Standards for reinforcing meshes require it to be tested in specified batch lots before it can be claimed to comply with those Standards. Hence Hurricane maintains two laboratories in New Zealand specifically to test manufactured reinforcing meshes for compliance and to provide test certification of those results. Hurricane Wire Products is in the unique position of being able to offer proof of compliance with all reinforcing meshes supplied. The following tests form the basis of the information required to provide the designer with confidence in the performance of the mesh at work. WELD SHEAR Weld Shear is a critical test for reinforcing meshes as the welded crosswire is often an integral part in the mechanics of lappage and provides the major proportion of the anchorage in concrete. Both NZS 3422 and AS/NZS 4671 requirements must be met to satisfy Hurricanes internal controls. DEFORMATION TEST The surface geometry of the reinforcing mesh plays a significant role in increasing the bond with the concrete. The relationship of the ribbed projections to the nominal diameter is critical and material tested must meet the requirements of AS/NZS MASS CALCULATION With the proliferation of deformed meshes the measurement of wire diameters became impractical; hence the measurement of mass now provides the evidence for design confidence. AS/NZS 4671 provides cross-sectional areal for nominal diameters and tolerances of 4.5% plus or minus on mass per metre results. TENSILE TEST The hard drawn nature of reinforcing wire produces high tensile strengths with low ductility. This prevents the observation of a yield phenomenon and hence the 0.2% proof stress is determined by test as detailed in both NZS 3422 and AS/NZS The minimum requirement remains at 485MPa. SET DOWN Set Down of the welded wires is not a test required by any Standards Authority. Rather it is an empirical measure from the experience gained from 60 years of manufacture by New Zealand s first mesh producer and is an effective indicator of the quality of the welding process.

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