'REDUCED DIG' INSTALLATION GUIDANCE

Transcription

1 Data Sheet No : SDI / B85PRD09 Issue 2 'REDUCED DIG' INSTALLATION GUIDANCE Gravel & Grassed Surfaces The Reduced Dig method of installation for is suitable for pedestrian and light vehicle applications where firm ground conditions already exist. It is particularly advantageous where there are budgetary limitations, restrictions on excavation due to SSSI conservation and archeological issues or Tree Preservation Orders (TPO). BENEFITS OF REDUCED DIG Minimal site preparation or variation to existing levels Reduced installation time and costs Reduced import of materials and disposal of debris Rapid establishment and usage of site after installation Compliant with current guidance for Sustainable Urban Drainage Systems (SUDS) Suitable for grass or gravel surfaces APPLICATIONS Light vehicle parking and access routes Pedestrian access & Cycle routes Tree root protection Golf buggy paths and Tow paths Caravan and Leisure site access routes Wheelchair and disabled access (DDA compliant) Light aircraft parking and taxiways SITE SUITABILITY Where existing ground conditions are firm (ie: CBR > 7%) and free draining or where a suitable hardcore/stone base already exists. Where trafficking is irregular or occasional BGT upper Geotextile filter fabric option with Grass or Gravel Sand : Soil Rootzone or Gravel Bedding DoT (GSB) Type 1 or reduced fines Type 3 Sub-base Where loads will not exceed that of cars and light vans Tensar TriAx geogrid option Subgrade soil BGT Lower Geotextile layer option Paving Grid Specification DESCRIPTION DATA Product Material Colour options Paver dimensions Installed Paver size Nominal internal cell size Structure Type Cell wall thickness Weight (Nominal) Load bearing capacity (filled) Crush Resistance (unfilled) Basal support & Anti-Shear Open cell % Connection type Interlock Mechanism Chemical resistance UV resistance Toxicity % recycled polyethylene Black, Green & Natural 500mm x 500mm x + 35mm ground spike 500mm x 500mm (4 grids per m 2 ) Castellated 67mm Plaque & 46mm Round Shaped Rigid-walled, flexible semi-closed cell combination 2.5mm 4.4mm 1.56 kg/paver - (6.24kg/m 2 ) < 400 tonnes/m 2 * < 250 tonnes/m 2 * Integral 35mm long Cross & T section ground spikes (18 per paver) Top 92% / Base 75% Overlapping Edge Loop & Cell connection Integral self locking Snap-Fit Clips Excellent High Non Toxic *Research carried out by Sheffield University Department of Mechanical Engineering. (Rennison/Allen March 2009)

2 - REDUCED DIG METHOD INSTALLATION METHODS After confirming that the ground conditions are suitably firm and free-draining for this type of reduced dig application, one of the following methods of installation should be followed. A. FOR GRASSED SURFACES 1. Cut the grass very close to the surface or where specified remove the turf/topsoil to a depth of <mm according to local levels. Dispose of all debris. Level the formation layer, lightly consolidate & install drains as specified. 2. Install edge retention as specified: Either tanalised timber boards, concrete, steel or plastic kerbs as appropriate. 3. Place a layer of Tensar TriAx geogrid on the formation layer and ensure it is flat to the surface by pinning as required. Note: An optional geotextile fabric layer (BGT) can be placed onto the formation prior to the Tensar TriAx geogrid installation, to prevent migration/contamination (see Note 2). 4. Place a 35 - thick bedding layer of 10-20mm diameter angular gravel / aggregate evenly over the geogrid. The geogrid must not be allowed to become exposed above the gravel / aggregate layer. 5. With the 2 sets of edge loop connectors facing in directions of laying, place the firmly onto the screeded bedding layer so that the ground spikes are pressed fully into the bedding and the base of the paver cells sit flat on the surface. Connect adjacent pavers together by slotting the edge cell connectors down into the edge loops (LOOPS ALWAYS LEAD). Pavers are locked in place by the integral snap-fit clips. Progress over the area in rows. Use protective gloves to avoid abrasions. 6. Pavers can be offset by 1 cell increments or cut to fit around obstructions & curves using a hand or power saw. The use of cut-pieces which do not have integral snap-fit connectors should be avoided wherever possible. 7. Fill pavers with the specified propriety rootzone to finished levels of 5-7mm below the top of the cells after settlement. A light whacker plate may be used to consolidate the pavers and settle rootzone fill. Do not overfill the cells. Additional settlement of the rootzone may occur where an open graded bedding is used, & further topping-up may be required. 8. Rootzone fill must be a free-draining, structurally sound propriety blend of sand:soil or sand:compost such as used in sports/golf construction & normally identified as a 60:40 or 70:30 ratio blend. The use of site-won materials or in-situ self-blending is NOT recommended without taking further advice. 9. Carry out a normal seeding, fertilising & watering programme. A very light top dressing may be applied to just cover the seed and to provide adequate germination conditions. Do not overfill the paver cells. Thin-cut or Washed Turf may be rolled into the surface as an alternative if required. 10. The surface may be trafficked immediately, but it is preferable to allow grass to fully establish prior to use. B. FOR RETAINED GRAVEL SURFACES After confirming that the ground conditions are suitably firm and free-draining for this type of reduced dig application, the following method of installation should be followed. 1. Follow steps 1-6 above. Note: An optional geotextile fabric layer (BGT) can be placed onto the formation prior to the Tensar TriAx geogrid installation (Step 3), to prevent migration/contamination (see Note 2). 2. Fill the pavers with the specified angular gravel or aggregate. Preferably a clean, evenly graded angular material with a range of 5-20mm diameter. Rounded 'pea gravel' is not recommended. 3. Consolidate the surface using a light vibratory whacker plate if required. 4. Refill any localised low areas with aggregate and repeat consolidation until satisfied with final compacted finish. 5. The surface can be trafficked immediately. Bedding Layer 35- thick layer of 10-20mm diameter, angular gravel or crushed aggregate. Optional Tensar TriAx geogrid layer and BGT geotextile (See note 2) Note 1: Determination of requirement for placement of an imported sub-base for the application and the required thickness of that sub-base material shall be determined by the strength and condition of the existing soils, the extent of allowable excavation and in consideration of the proposed traffic loadings. Standard Bodpave 85 Access Route design may apply. Certain ground conditions may require placement of a drainage system within the design. Note 2: Specific site criteria will determine if Tensar TriAx geogrid &/or BGT Geotextile are required. Note 3: Maximum advised gradient for traffic applications: 12% (1:8) 7º. Bodpave 85 has specific pegging points if required for steep slope applications. Pegging is not necessary for standard access route applications. Note 4: complies with BS8300: Design of buildings and their approaches to meet the needs of disabled people - Code of Practice. (ISBN ) & Building Regulations Document M section 6. For product specification please refer to the Design documents for use in Grassed & Gravel Surfaces. Specific advice on the use of on steep slopes, drainage suitability and Sustainable Urban Drainage Systems (SUDS) applications, can be obtained from Fiberweb Geosynthetics Ltd. Tensar & TriAx are registered trademarks of Tensar International Existing soil profile or stone base (see note 1) 35- deep open-celled plastic pavers. Filled with 60:40 sand/soil or sand/compost rootzone blend. Then seeded and fertilised. Or Filled with selected gravel/angular aggregate (5-20mm dia.) The information contained herein is, to the best of our knowledge, accurate in all material respects. However, since the circumstances and conditions in which such information and the products mentioned herein can be used may vary and are beyond our control, no representation or warranty, express or implied, of any nature whatsoever is or will be made and no responsibility or liability is or will be accepted by us, any of our affiliates or our or their respective directors, officers, employees or agents in relation to the accuracy or completeness or use of the information contained herein or any such products and any such liability is expressly disclaimed.

3 SPECIFICATION, DESIGN & INSTALLATION GUIDANCE For Gravel Surfaces Typical Construction Profile Optional geotextile fabric BGT (see Notes 4, 6 & 7) BodPave 85 paver cells filled with angular aggregate in range 5mm - 20mm (BS EN 13242) Data Sheet No : SDI / B85PGV09 Issue 2 Bedding layer: 35- thick angular aggregate within the range of 5mm - 20mm (BS EN 13242) (see Note 8) Vertical edging board or kerb min = Tx Tx -380mm Sub-base layer. Thickness (Tx) & Type as determined by Table 1 & Notes 1-5 Subgrade Soil (subsoil) (Refer to Table 1, Chart 1 & Note 5) BODPAVE 85 INSTALLATION METHOD Tensar TriAx geogrid & optional geofabric BGT (see Table 1, 2 & Notes 1-4 & 7) Drainage options (see Notes 2, 4, 6 & 7) 1. Install edge retention as specified: Either tanalised timber boards, concrete, steel or plastic kerbs as appropriate. 2. Ensure that the gravel/aggregate bedding layer is the correct & uniform thickness, is level & well consolidated. 3. Place the paver units: With the 2 sets of edge loop connectors facing in directions of laying, place firmly onto the surface so that its ground spikes are pressed fully into the bedding and the base of the paver cells sit flat on the bedding layer surface. Connect adjacent pavers together by slotting the edge cell connectors down into the edge loops (LOOPS ALWAYS LEAD) & progress over the area in rows. Pavers are locked in place by snap-fit clips. If paver separation is required, clips can be dislocated using careful, firm hand or screwdriver pressure or by gently twisting the paver joints. Use protective gloves to avoid abrasions. 4. Pavers can be offset by 1 cell increments or cut to fit around obstructions & curves using a hand or power saw. The use of cut-pieces which do not have integral snap-fit connectors should be avoided wherever possible. 5. Fill pavers with specified angular decorative gravel/aggregate to finished levels. A light whacker plate may be used to consolidate the pavers and settle the fill. Top up the cells as required after settlement. It is preferable not to overfill the cells. The use of rounded pea gravel is not recommended. 6. If the area is to be used for horses, it may be preferable to cover the surface with 50 mm of a fine sand or bark mulch. 7. The surface may be trafficked immediately. DESIGN NOTES Note 1: If Tensar TriAx geogrid is omitted, the total Granular Sub-Base (GSB) layer thickness (Tx) must be increased by minimum 50%. Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8: Note 9: Note 10: A DoT Type 1 sub-base may be used provided that an adequate drainage system is installed. Alternatively, a permeable/open-graded (reduced fines) sub-base layer (i.e Type 3) may be specified, e.g. as part of a Sustainable Urban Drainage System (SUDS). If construction traffic axle loads will be greater than 60kN (approx 6 Tonnes), minimum sub-base thickness over Tensar TriAx geogrid shall be 1. Maximum sub-base particle size should match minimum sub-base thickness but not exceed 75mm diameter. For sub-base thicknesses of around mm, a minimum 37.5mm particle size should be adopted to allow effective installation of Tensar TriAx geogrid Where drains are omitted and a 'reduced fines' sub-base is specified for SUDS, this may be covered with a geotextile fabric (i.e. BGT) to avoid contaminants leaching into the sub-base. Specific advice on CBR% strengths, ground conditions and construction over weak ground with a CBR less than 1% is available from Boddingtons Limited. CBR% = California Bearing Ratio, a measurement of subgrade soil strength. Typical standard drainage detail: mm diameter perforated pipe drains laid at minimum gradient 1:, bedded on gravel in trench backfilled with DoT Type A drainage aggregate, trench covered &/or wrapped with a geotextile fabric (i.e BGT), pipes leading to a suitable outfall or soakaway. Drains installed down centre or one edge of areas up to 5m wide. Wider areas may require additional lateral drains at 5m - 10m centres. Drainage design to be determined by the specifier based on specific site conditions. Drainage for a Sustainable Urban Drainage System (SUDS) application will vary according to the site but generally omits the requirement for extensive pipe & trench drainage systems within the sub-base layer and may require an additional layer of BGT geotextile fabric at base of construction. The selected gravel fill & bedding should be clean, free-draining, angular shaped material in the specified size range. Maximum advised gradient for traffic applications: 12% (1:8) 7º. Bodpave 85 has specific pegging points if required for steep slope applications. Pegging is not necessary for standard access route applications. complies with BS8300: Design of buildings and their approaches to meet the needs of disabled people - Code of Practice. (ISBN ) & Building Regulations Document M section 6. Specific advice on the use of on steep slopes, drainage suitability and Sustainable Urban Drainage Systems (SUDS) applications, can be obtained from Fiberweb Geosynthetics Limited.

4 Data Sheet No : SDI / B85PGV09 Issue 2 Table 1: Typical Sub-base Thickness (Tx) Requirements - refer to construction profile overleaf APPLICATION/LOAD Fire trucks, Coaches and occasional HGV access Light vehicle access and overspill car parking Table 2: Paving Grid Specification CBR (%) STRENGTH OF SUBGRADE SOIL (see Chart 1) (TX) DoT SUB-BASE THICKNESS (mm) (see Notes 1-5) TENSAR TriAx GEOGRID (see Notes 1-3) DESCRIPTION Product Material Colour options Paver dimensions Installed Paver size Nominal internal cell size Structure Type Cell wall thickness Weight (Nominal) Load bearing capacity (filled) Crush Resistance (unfilled) Basal support & Anti-Shear Open cell % Connection type Interlock Mechanism Chemical resistance UV resistance Toxicity Bedding Layer Paver fill Sub-base type Sub-base reinforcement Geotextile Fabric DATA % recycled polyethylene Black, Green & Natural 500mm x 500mm x + 35mm ground spike 500mm x 500mm (4 grids per m 2 ) Castellated 67mm Plaque & 46mm Round Shaped Rigid-walled, flexible semi-closed cell combination 2.5mm 4.4mm 1.56 kg/paver - (6.24kg/m 2 ) < 400 tonnes/m 2 * < 250 tonnes/m 2 * Integral 35mm long Cross & T section ground spikes (18 per paver) Top 92% / Base 75% Overlapping Edge Loop & Cell connection Integral self locking Snap-Fit Clips Excellent High Non Toxic 35 - thick of 5 20mm clean, angular aggregate (BSEN13242) To top of cells using 5 20mm clean, angular aggregate (BSEN13242) DoT Type 1 or a modified permeable Type 3 sub-base (Table 1 & Notes 1-5) Tensar TriAx geogrid (Table 1 & Notes 1-4 & 7)-Specification on request. BGT Geotextile where appropriate Chart 1: Field guidance for estimating sub-grade strengths Consistency Tactile (feel) Indicator Visual (observation) Strength Mechanical CBR CU (test) SPT % kn/sqm Very Soft Hand sample squeezes through fingers Man standing will sink >75mm <2 <1 <25 Soft Easily moulded by sinks 50-70mm 2-4 Around 1 Around 25 Medium Moulded by moderate sinks 25mm Firm Moulded by strong Utility truck ruts 10-25mm Stiff Cannot be moulded but can be indented by thumb Loaded construction vehicle ruts by 25mm This field guide is provided as an aid to assessing the mechanical stabilisation requirements in commonly encountered site conditions. Fiberweb Geosynthetics Limited accepts no responsibility for any loss or damage resulting from the use of this guide. *Research carried out by Sheffield University Department of Mechanical Engineering. (Rennison/Allen March 2009) The information contained herein is, to the best of our knowledge, accurate in all material respects. However, since the circumstances and conditions in which such information and the products mentioned herein can be used may vary and are beyond our control, no representation or warranty, express or implied, of any nature whatsoever is or will be made and no responsibility or liability is or will be accepted by us, any of our affiliates or our or their respective directors, officers, employees or agents in relation to the accuracy or completeness or use of the information contained herein or any such products and any such liability is expressly disclaimed. Tensar. & TriAx are registered trademarks of Tensar International

5 SPECIFICATION, DESIGN & INSTALLATION GUIDANCE For Grassed Surfaces Typical Construction Profile Optional vertical edging board or kerb BodPave 85 paver cells filled to within 5-7mm of the surface with 60:40 rootzone (see Note 8) then seeded or turfed and fertilised BGT Geotextile fabric (see Notes 4, 6 & 7) Data Sheet No : SDI / B85PGS09 Issue 2 Bedding layer: 50-70mm thick consolidated 60:40 rootzone (see Note 8) mm min = Tx Tx -380mm Sub-base layer. Thickness (Tx) & Type as determined by Table 1 & Notes 1-5 Subgrade Soil (subsoil) (Refer to Table 1, Chart 1 & Note 5) BODPAVE 85 INSTALLATION METHOD Tensar TriAx geogrid & optional BGT Geotextile fabric (see Tables 1, 2 & Notes 1-4 & 7) Drainage options (see Notes 2, 4, 6 & 7) 1. Install edge retention as specified: Either tanalised timber boards, concrete, steel or plastic kerbs as appropriate. 2. Ensure that the sand:soil rootzone bedding layer is the correct & uniform thickness, is level & well consolidated. 3. Place the paver units: With the 2 sets of edge loop connectors facing in directions of laying, place firmly onto the surface so that its ground spikes are pressed fully into the bedding and the base of the paver cells sit flat on the bedding layer surface. Connect adjacent pavers together by slotting the edge cell connectors down into the edge loops (LOOPS ALWAYS LEAD) & progress over the area in rows. Pavers are locked in place by snap-fit clips. If paver separation is required, clips can be dislocated using careful, firm hand or screwdriver pressure or by gently twisting the paver joints. Use protective gloves to avoid abrasions. 4. Pavers can be offset by 1 cell increments or cut to fit around obstructions & curves using a hand or power saw. The use of cut-pieces which do not have integral snap-fit connectors should be avoided wherever possible. 5. Fill pavers with specified propriety rootzone to finished levels: 5-7mm below top of the cells after settlement. A light whacker plate may be used to consolidate the pavers and settle rootzone fill. Do not overfill or over consolidate. 6. Carry out a normal seeding, fertilising & watering programme. A light top dressing may be applied to just cover the seed and to provide adequate germination conditions. Do not overfill the paver cells. Thin-cut or Washed Turf may be lightly rolled into the surface as an alternative if required. 7. The surface may be trafficked immediately for critical access purposes, but it is preferable to allow grass to fully establish prior to use. DESIGN NOTES Note 1: If Tensar TriAx geogrid is omitted, the total Granular Sub-Base (GSB) layer thickness (Tx) must be increased by minimum 50%. Note 2: A DoT Type 1 sub-base may be used provided that an adequate drainage system is installed. Alternatively, a permeable/open-graded (reduced fines) sub-base layer (i.e Type 3) may be specified, e.g. as part of a Sustainable Urban Drainage System (SUDS). Note 3: If construction traffic axle loads will be greater than 60kN (approx 6 Tonnes), minimum sub-base thickness over Tensar TriAx geogrid shall be 1. Maximum sub-base particle size should match minimum sub-base thickness but not exceed 75mm diameter. For sub-base thicknesses of around mm, a minimum 37.5mm particle size should be adopted to allow effective installation of Tensar TriAx geogrid. Note 4: Where drains are omitted and a 'reduced fines' sub-base is specified for SUDS this must be covered with either a geotextile fabric (i.e. BGT) and/or a clean, suitably graded gravel blinding to avoid the bedding layer leaching into the sub-base. Note 5: Specific advice on CBR% strengths, ground conditions and construction over weak ground with a CBR less than 1% is available from Boddingtons Limited. CBR% = California Bearing Ratio, a measurement of subgrade soil strength. Note 6: Typical standard drainage detail: mm diameter perforated pipe drains laid at minimum gradient 1:, bedded on gravel in trench backfilled with DoT Type A drainage aggregate, trench covered &/or wrapped with a geotextile fabric (i.e BGT), pipes leading to a suitable outfall or soakaway. Drains installed down centre or one edge of areas up to 5m wide. Wider areas may require additional lateral drains at 5m - 10m centres. Drainage design to be determined by the specifier based on specific site conditions. Note 7: Drainage for a Sustainable Urban Drainage System (SUDS) application will vary according to the site but generally omits the requirement for extensive pipe & trench drainage systems within the sub-base layer and may require an additional layer of BGT geotextile fabric at base of construction. Note 8: Rootzone bedding and paver fill must be a free-draining, structurally sound propriety blend of sand:soil or sand:compost such as used in sports/golf construction & normally identified as a 60:40 or 70:30 ratio blend. The use of site-won materials or in-situ self-blending is NOT recommended without taking further advice. Note 9: Maximum advised gradient for traffic applications: 12% (1:8) 7º. Bodpave 85 has specific pegging points if required for steep slope applications. Pegging is not necessary for standard access route applications. Note 10: complies with BS8300: Design of buildings and their approaches to meet the needs of disabled people - Code of Practice. (ISBN ) & Building Regulations Document M section 6. Specific advice on the use of on steep slopes, drainage suitability and Sustainable Urban Drainage Systems (SUDS) applications, can be obtained from Fiberweb Geosynthethics Ltd.

6 Data Sheet No : SDI / B85PGS09 Issue 2 Table 1: Typical Sub-base Thickness (Tx) Requirements - refer to construction profile overleaf APPLICATION/LOAD Fire trucks, Coaches and occasional HGV access Light vehicle access and overspill car parking Table 2: Paving Grid Specification CBR (%) STRENGTH OF SUBGRADE SOIL (see Chart 1) (TX) DoT SUB-BASE THICKNESS (mm) (see Notes 1-5) TENSAR TriAx GEOGRID (see Notes 1-3) DESCRIPTION DATA Product Material Colour options Paver dimensions Installed Paver size Nominal internal cell size Structure Type Cell wall thickness Weight (Nominal) Load bearing capacity (filled) Crush Resistance (unfilled) Basal support & Anti-Shear Open cell % Connection type Interlock Mechanism Chemical resistance UV resistance Toxicity Bedding Layer Paver fill (seed bed) Grass seed or turf Fertiliser Sub-base type Sub-base reinforcement Chart 1: Field guidance for estimating sub-grade strengths Consistency Very Soft Tactile (feel) Hand sample squeezes through fingers % recycled polyethylene Black, Green & Natural 500mm x 500mm x + 35mm ground spike 500mm x 500mm (4 grids per m 2 ) Castellated 67mm Plaque & 46mm Round Shaped Rigid-walled, flexible semi-closed cell combination 2.5mm 4.4mm 1.56 kg/paver - (6.24kg/m 2 ) < 400 tonnes/m 2 * < 250 tonnes/m 2 * Integral 35mm long Cross & T section ground spikes (18 per paver) Top 92% / Base 75% Overlapping Edge Loop & Cell connection Integral self locking Snap-Fit Clips Excellent High Non Toxic 60:40 rootzone (see Note 8) : 50-70mm thick 60:40 rootzone (see Note 8): 43-45mm thick 35g/m 2 amenity blend low maintenance seed or turf as required Pre-seed fertiliser followed up with appropriate seasonal fertiliser DoT Type 1 or a modified permeable Type 3 sub-base (Table 1 & Notes 1-5) Tensar TriAx geogrid (Table 1 & Notes 1-4 & 7)-Specification on request. Indicator Visual (observation) Man standing will sink >75mm Strength Mechanical CBR CU (test) SPT % kn/sqm <2 <1 <25 Soft Easily moulded by sinks 50-70mm 2-4 Around 1 Around 25 Medium Moulded by moderate sinks 25mm Firm Moulded by strong Utility truck ruts 10-25mm Stiff Cannot be moulded but can be indented by thumb Tensar & TriAx are registered trademarks of Tensar International Loaded construction vehicle ruts by 25mm This field guide is provided as an aid to assessing the mechanical stabilisation requirements in commonly encountered site conditions. Fiberweb Geosynthethics Ltd accepts no responsibility for any loss or damage resulting from the use of this guide. *Research carried out by Sheffield University Department of Mechanical Engineering. (Rennison/Allen March 2009) The information contained herein is, to the best of our knowledge, accurate in all material respects. However, since the circumstances and conditions in which such information and the products mentioned herein can be used may vary and are beyond our control, no representation or warranty, express or implied, of any nature whatsoever is or will be made and no responsibility or liability is or will be accepted by us, any of our affiliates or our or their respective directors, officers, employees or agents in relation to the accuracy or completeness or use of the information contained herein or any such products and any such liability is expressly disclaimed.