Maccaferri Ltd 7400 The Quorum Oxford Business Park North Garsington Road Oxford OX4 2JZ Tel: Fax:

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1 Maccaferri Ltd 7400 The Quorum Oxford Business Park North Garsington Road Oxford OX4 2JZ Tel: Fax: CI/SfB (16.9 Jn6 Roads and Bridges Agrément Certificate No 00/R119 Designated by Government to issue European Technical Approvals MACCAFERRI TERRAMESH SYSTEM FOR REINFORCED SOIL EMBANKMENTS Maille hexagonale Sechseckige Masche Product THIS CERTIFICATE RELATES TO THE MACCAFERRI TERRAMESH SYSTEM, HEXAGONAL MESH UNITS FOR USE AS REINFORCEMENT IN EMBANKMENTS WITH SLOPE ANGLES OF UP TO 70. The products provide lateral restraint to suitable cohesive or frictional soils in embankments, with stability achieved by the interaction and interlocking of the soil particles and the Maccaferri Terramesh System. The design and construction of embankments must be in accordance with the requirements of the Department of the Environment, Transport and the Regions, Highways Agency (DETR, HA and the conditions set out in the Design Data and Installation parts of this Certificate. Maccaferri Terramesh System units are marketed by Maccaferri Ltd and manufactured by the Maccaferri Group. Department of the Environment, Transport and the Regions, Highways Agency Requirements 1 Requirements 1.1 Approval procedures shall be in accordance with the Department of the Environment, Transport and the Regions, Highways Agency (DETR, HA Standard HD22 Ground Investigation and Earthworks Procedure for Geotechnical Certification (DMRB The products are for use in embankments with an effective slope angle of up to The design, materials specification and construction methods adopted shall be in accordance with DETR, HA Advice Note HA68 Design Methods for the Reinforcement of Highway Slopes by Reinforced Soil and Soil Nailing Techniques (DMRB and Manual of Contract Documents for Highway Works Volume 1 Specification for Highway Works (MCHW1 March 1998 Edition. Technical Specification 2 Description 2.1 A Maccaferri Terramesh System unit comprises a horizontal panel faced at one end with a gabion box, formed from hexagonal, PVC-U coated, galvanized, double twist woven steel mesh. The front and top of the gabion box are folded during manufacture. The back and sides of the gabion box are formed from a separate piece of the mesh which is folded and fixed to the horizontal panel during manufacture. Additional, separate, diaphragm (partition mesh panels can be fixed on site to the gabion box facing as required by the design (see Figure 1. Readers are advised to check the validity of this Certificate by either referring to the Index of Current BBA Publications or contacting the BBA direct (Telephone Hotline

2 Figure 1 Construction of Terramesh unit 2.2 The wire mesh and gabion boxes (manufacturer s reference P8/2.7 see Figure 2 are available in a range of nominal sizes (metres: width 2.0 length 3.0, 4.0 or 5.0 height 0.5 or 1.0 Figure 2 Details of hexagonal mesh 80 mm 2.3 The wire used to manufacture the mesh complies with BS EN : 1998 with a tensile strength of between 350 and 500 Nmm 2 and with a minimum elongation at failure of 10%. 2.4 The wire is either galvanized in accordance with BS 443 : 1982(1990 or galfan (1 coated in accordance wtih ASTM A 856/A 856M : 1997 prior to being coated with PVC-U (see Table 1. (1 Galfan a 95% zinc, 5% aluminium alloy. Table 1 General wire specification Wire Minimum zinc Minimum overall Steel core type or galfan coating diameter diameter (gm 2 (mm (mm Main (±0.06 Edge and selvedge (±0.08 Lacing (± Each mesh panel is edged and laced with galvanized, PVC-U coated, steel wire. The various types of wire (main, edge and selvedge, and lacing have the specification given in Table 1. 3 Manufacture and quality control 3.1 PVC-U coated galvanized wire is manufactured by the Maccaferri Group or obtained from an approved supplier providing mill certificates for the steel and a Certificate of Conformity to the Maccaferri Group s specification. 2

3 3.2 The wire is woven into a hexagonal pattern, with double twist joints and larger diameter wire is introduced along the edge. The mesh is cut to the required length, the selvedge edge wire positioned and cut ends twisted into the panel. The rear panel is fixed to the main one while the diaphragm panels are provided not assembled; the units are folded and packed ready for delivery. 3.3 Factory production control includes visual and dimensional checks on the incoming wire coil, checks on the quantity of the zinc coating, thickness of the plastic coating, and dimensional checks on the woven mesh. 4 Delivery, storage and site handling 4.1 The units are delivered to site in bundles weighing between 600 kg and 700 kg depending on unit size. 4.2 The products should be stored away from site traffic to avoid the risk of accidental damage, and should remain packaged until required. 4.3 A label bearing the BBA Certificate number, manufacturer s name, batch number and product code is attached to each bundle. 4.4 Bundles must be handled with care to avoid damage to the coating. Individual units may be manhandled. Design Data 5 General 5.1 Maccaferri Terramesh System units are satisfactory for use as metallic reinforcement to embankments with maximum slope angles of 70. Structural stability is achieved through frictional interaction and mechanical interlocking of soil particles with the product. 5.2 Prior to the commencement of the work, the designer should satisfy the DETR, HA geotechnical certification requirements. 5.3 The product may be used: in combination with soil types having an effective angle of shearing resistance in the range of 15 to 50, and where the design is in accordance with the procedures given in HA68 (DMRB Practicability of installation 6.1 Provided the appropriate reduction factor for mechanical damage has been included at the design stage to allow for the installation methods employed and the type of fill permitted, the product can be readily installed in accordance with the construction drawings. 6.2 Prior to and during installation, particular care should be taken to ensure: 3 site preparation and embankment construction are as detailed in section 10 fill properties satisfy the design specification drainage is adequate at all stages of construction, as required by the contract documents the product is protected against damage from site traffic and installation equipment the stability of existing structures is not affected. 7 Design considerations 7.1 For reinforced embankment projects in the UK, when designs are carried out by, or on behalf of, Maccaferri Ltd, they are in accordance with the procedures given in HA68 (DMRB Fill properties 7.2 The designer should specify the relevant properties of a fill material deemed acceptable for the purpose of the design. Acceptable materials should meet the requirements of MCHW1 and HA68 (DMRB Mechanical properties Tensile strength 8.1 The characteristic long-term tensile strength (P c of Terramesh (1 for the required design life of 60 years is: P c = 46.0 knm 1(2 (1 The contribution of the zinc and PVC-U coatings to the yield strength of the product is minimal and should be ignored. (2 load is applied parallel to the axis of twist of the mesh according to ASTM A 975 : Material safety factors 8.2 In establishing the design strength of the product and ensuring that during the life of the embankment the reinforcement will not fail in tension, the BBA recommends that in line with the method of HA68 (DMRB 4.1.4, a set of partial material safety factors should be applied to the value for long-term strength (P c. Conditions of use outside the scope for which partial safety factors are defined, are not covered by this Certificate. Manufacture and extrapolation of data partial safety factor (f m 8.3 To allow for variation in manufacture and product dimensions and to account for extrapolation of data, the value for the factor f m may be selected from Table 2. Table 2 Partial material safety factor manufacture and extrapolation of data Design life (years Safety factor (f m Installation damage partial safety factor (f d 8.4 To allow for loss of strength due to mechanical damage that may be sustained during

4 installation, the appropriate value for f d may be selected from Table 3. The partial safety factors given for site damage assume that well-graded material is used (coefficient of uniformity >5 and with a minimum compacted depth of 150 mm. For soils not covered by Table 3, appropriate values of f d may be determined from site specific trials. Table 3 Partial material safety factor mechanical installation damage (f d Fill material Maximum particle Safety factor size (mm (f d Silts and clays < Sands Gravels Environmental effects partial safety factor (f e 8.5 To account for environmental conditions the appropriate value for f e may be selected from Table 4. For soils with ph values outside the range quoted, consideration should be given to an increased value for f e. Table 4 Partial material safety factor environmental effects Table 5 Typical values of bond coefficient (f b and direct sliding coefficient (f ds Fill type Maximum D 60 PI f b f ds particle size D 10 (% (mm (degrees Well graded, ~ crushed limestone aggregate Well graded, ~ angular sand Uniformly 2 30 ~ graded, rounded sand High plasticity silty clay Direct sliding 8.9 The direct sliding resistance of the Terramesh System reinforcement may be expressed as: f ds tan where f ds is a direct sliding coefficient [synonymous with the term interface sliding factor ( defined in HA68]. ( tan f ds = a s + (1 a s tan Soil ph level (ph Safety factor (f e Design load (P des 8.6 The maximum design load (P des that the reinforcement can be relied upon to deliver at the end of the design life and at the design temperature can be calculated from the equation: P c P des = f d.f e.f m Fill/Terramesh interaction Bond strength 8.7 The bond strength for the product reinforcement may be expressed as: f b tan where f b is the bond coefficient [synonymous with the term bearing factor ( ' defined in Advice Note HA68]. 8.8 The use of laboratory pull-out testing to determine the value of the bond coefficient (f b is not recommended at present. For routine design purposes, values may be estimated using the theoretical method of Jewell (CIRIA SP123, For the product conservative values may be taken from Table 5. The BBA recommend that site specific pull-out testing is carried out to confirm the value of bond coefficient (f b used in the final design. where ( tan is the coefficient of skin friction (f sf, and tan a s is the proportion of plane sliding area that is solid For the Terramesh System the coefficient of skin friction (f sf may be assumed, for routine design purposes, to be 0.6 for compacted frictional fill ( =30. This is a conservative value. Measured values of f ds for typical soils are given in Table 5. Formulae notation = angle of friction between soil and plane reinforcement surface =angle of friction of soil. 9 Durability 9.1 The product may be used in soils normally encountered in civil engineering practice. 9.2 Evidence from tests show that the product has good resistance to chemical corrosion, biodegradation, temperature effects and ultraviolet exposure. 9.3 In the opinion of the BBA, when used and installed in accordance with this Certificate, Terramesh can be used to achieve a design life of 60 years as required by DETR, HA for embankments. 4

5 Installation Technical Investigations 10 General Care should be exercised to ensure Terramesh is laid with the longitudinal direction parallel to the direction of principal stress. 11 Preparation The formation is prepared by levelling and compacting the subgrade in accordance with MCHW1. The surface must be free of root growth, logs, frozen matter and any other obstacles that may damage the geogrids. 12 Procedure 12.1 The units are unfolded and the external face is assembled by wiring up vertical faces following the procedure detailed in BBA Roads and Bridges Agrément Certificate No 93/R075, and spread over the prepared formation. The box gabion parts of adjacent units are securely fixed together, ensuring that the horizontal panels abut each other. The horizontal panels need not be joined together The boxes forming the face are filled using the method recommended for standard gabions in BBA Roads and Bridges Agrément Certificate No 93/R075 (see Figure 3. Figure 3 Terramesh installation The following is a summary of the technical investigations carried out on the Maccaferri Terramesh System. 13 Investigations 13.1 The manufacturing process of the units was examined, including the methods adopted for quality control, and details were obtained of the quality and composition of the materials used An assessment of data was made to determine: dimensional accuracy tensile strength quality of galvanized coating performance of wire, mesh and filled gabions quality of plastic coating ease of assembly durability Site visits were carried out to assess the practicability, ease of handling and installation under various site conditions An assessment was made of data pertaining to site case studies where the product has been in use for a number of years. Additional Information The management systems of Maccaferri SpA have been assessed and registered as meeting the requirements of UNI EN ISO , for the manufacture of gabions, by Bureau Veritas Quality Internal Italie (Certificate Number Bibliography one unit installed and next positioned 12.3 Fill is placed to a minimum depth of 150 mm, with particular care being taken to ensure that the grids are adequately covered before compaction or trafficking. Construction traffic will damage the unprotected system Maximum thickness of compaction layers depends on the type of fill and compaction equipment employed, but depths should not exceed 500 mm. 5 BS 443 : 1982(1990 Specification for testing zinc coatings on steel wire and for quality requirements BS EN : 1998 Hexagonal steel wire netting for engineering purposes ASTM A 856/A 856M : 1997 Standard specification for Zinc-5% Aluminium-Mischmetal Alloy-Coated Carbon Steel Wire ASTM A 975 : 1997 Standard specification for Double-Twisted Hexagonal Mesh Gabions and Revet Mattresses CIRIA SP123 : 1996 Soil Reinforcement with Geotextiles UNI EN ISO 9002 : 1994 Quality systems. Model for quality assurance in production, installation and servicing

6 Conditions of Certification 14 Conditions 14.1 This Certificate: (a relates only to the product that is described, installed, used and maintained as set out in this Certificate; (b is granted only to the company, firm or person identified on the front cover no other company, firm or person may hold or claim any entitlement to this Certificate; (c has to be read, considered and used as a whole document it may be misleading and will be incomplete to be selective; (d is copyright of the BBA References in this Certificate to any Act of Parliament, Regulation made thereunder, Directive or Regulation of the European Union, Statutory Instrument, Code of Practice, British Standard, manufacturers instructions or similar publication, shall be construed as references to such publication in the form in which it was current at the date of this Certificate This Certificate will remain valid for an unlimited period provided that the product and the manufacture and/or fabricating process(es thereof: (a are maintained at or above the levels which have been assessed and found to be satisfactory by the BBA; (b continue to be checked by the BBA or its agents; (c are reviewed by the BBA as and when it considers appropriate; and (d remain in accordance with the requirements of the Department of the Environment, Transport and the Regions, Highways Agency In granting this Certificate, the BBA makes no representation as to: (a the presence or absence of any patent or similar rights subsisting in the product or any other product; (b the right of the Certificate holder to market, supply, install or maintain the product; and (c the nature of individual installations of the product, including methods and workmanship Any recommendations relating to the use or installation of this product which are contained or referred to in this Certificate are the minimum standards required to be met when the product is used. They do not purport in any way to restate the requirements of the Health & Safety at Work etc Act 1974, or of any other statutory, common law or other duty which may exist at the date of this Certificate or in the future; nor is conformity with such recommendations to be taken as satisfying the requirements of the 1974 Act or of any present or future statutory, common law or other duty of care. In granting this Certificate, the BBA does not accept responsibility to any person or body for any loss or damage, including personal injury, arising as a direct or indirect result of the installation and use of this product. In the opinion of the British Board of Agrément, the Maccaferri Terramesh System is fit for its intended use provided it is installed, used and maintained as set out in this Certificate. Certificate No 00/R119 is accordingly awarded to Maccaferri Ltd. On behalf of the British Board of Agrément Date of issue: 28th January 2000 Chief Executive British Board of Agrément P O Box No 195, Bucknalls Lane Garston, Watford, Herts WD2 7NG Fax: mail@bba.star.co.uk For technical or additional information, tel: For information about Agrément Certificate validity and scope, tel: Hotline: