A grid layer is placed. The design thickness of granular fill is placed, spread and compacted.

Details of Enhanced Arch LTP at Second Severn Crossing.

Foundations over Piles

Constructing Load TransferPlatforms over weak ground

with piled foundations

Second Severn Crossing Enhanced Arch Load Transfer Platform performance.

©Copyright Tensar International Limited

Printed August 2010 Issue 11, SDA: 583090

The information in this brochure is supplied by Tensar International free of charge. Tensar International donot assume any duty of care to you or any third party. No liability for negligence (other than for deathand personal injury) can arise from any use of or reliance on the information in this brochure or use ofany Tensar International product mentioned. Tensar International will not be liable if this brochurecontains any misrepresentation or misstatement. Determination of the suitability for any project of theinformation and any Tensar International product mentioned in it must be made by your engineer orother professional advisor who has full knowledge of the project. You, together with any such engineeror advisor, must assume all risk of loss and damage of any kind arising from use of the information or anyproduct of Tensar International other than the risk of death and personal injury. If you or any third partysubsequently purchases a product referred to in this brochure or any other Tensar International productthe entire terms of the contract of purchase and the entire obligation of Tensar International relating tothe product or arising from its use shall be as set out in Tensar International's Standard Conditions inforce at the time of purchase, a copy of which may be requested from Tensar International. Tensar andTensartech are trade marks of tensar International Limited.

Construction of an Enhanced Arch Load Transfer PlatformSmall pile caps being cast prior to constructing the Enhanced Arch Load Transfer Platform.

Once the supporting piles/VCCs have been installed thesimple construction process involves the inclusion of 2 or 3layers of Tensar geogrids in the granular layers above thesupports. Dead weight compaction of the cushion layer offill under the bottom grid, and the layer of fill between the

bottom two grids, is the only deviation from standardembankment placement and compaction operations.Overlapping, or tying, of adjacent grids provides thecontinuity required.

Second Severn Crossing, UKThe Toll Plaza area for the Second Severn Crossing in theUK was built over compressible soils supported on VCCs.Load from the embankment and pavement above wastransmitted to the VCCs using a Tensar geogrid reinforcedEnhanced Arch Load Transfer Platform (LTP). The graphssummarise the performance from monitoring this LTP.Settlement above the VCCs and mid-way between them isalmost the same, whereas stress measured at subgrade

level between the VCCs is almost zero. These results showhow well the design assumptions have been realised inpractice. The Enhanced Arch LTP has performed as a stiffraft, transmitting loads from the pavement andembankment directly to the VCCs using the excellent loadspreading capability of a granular layer reinforced withTensar biaxial geogrids.

Q 05288ISO 9001:2008

EMS 86463ISO 14001:2004

Tel: +44 (0)1254 262431

Fax: +44 (0)1254 266868

E-mail: info@tensar.co.uk

www.tensar-international.com

Tensar International Limited

Cunningham Court

Shadsworth Business Park

Blackburn BB1 2QX

United Kingdom

Contact Tensar International or your local distributor to receive furtherliterature covering Tensar products and applications.

Also available on request are product specifications, installation guidesand specification notes.

The complete range of Tensar literature consists of:

• Tensar Geosynthetics in Civil Engineering A guide to products,systems and services

• Ground Stabilisation Reinforcing unbound layers in roads andtrafficked areas

• TriAx™ A Revolution in Geogrid Technology The properties andperformance advantages of Tensar TriAx™ geogrids

• Asphalt Pavements Reinforcing asphalt layers in roads andtrafficked areas

• Tensartech Earth Retaining Systems Bridge abutments, retainingwalls and steep slopes

• Railways Mechanical stabilisation of track ballast and sub-ballast

• Foundations over Piles Constructing over weak ground withoutsettlement

• Basal Reinforcement Using Basetex high strength geotextiles

• Tensartech Geocell Mattress System

• Erosion Controlling erosion on soil and rock slopes

Your local distributor is:

For

det

ails

of

Ten

sar

wo

rksh

op

s vi

sit

ww

w.t

ensa

r-in

tern

atio

nal

.co

m

Engineers often need to construct embankments in areas whereminimal settlement can be tolerated. This is especially true whenthe serviceability of adjacent structures would be compromisedby anything other than minimal settlement. The engineer,therefore, needs to design a foundation that will provide a firmsupport without the consequential settlements andconsolidation of underlying soils.

Using a Load Transfer Platform (LTP) avoids the delay requiredfor consolidation settlement as a result of placing embankmentfill over soft, compressible soils. The Tensar Load TransferPlatform distributes embankment loads efficiently onto a seriesof piles or vibro concrete columns (VCCs) which bear on firmerstrata below. This avoids the cost of using a concrete raft. Insituations where the foundation soils can be assured to providesome permanent support to the area between the piles, then aLTP of good quality granular fill reinforced with multiple layersof Tensar grids can be used. In all other installations analternative design, using Tensar Basetex, can be employed and

Load Transfer Mechanismsor a concrete slab to ensure that the arch is permanentlylocked in compression.

As the embankment height increases the lateral forceswithin the embankment increase and these must beresisted by reinforcement anchored at the embankmentedge, to prevent the forces being imposed on the verticalpiles. Raking piles can be used as an alternative althoughfor some types of pile, e.g. vibro concrete columns, thismay be impractical.

Tensioned Membrane

Load Transfer Platform (LTP)A Tensioned Membrane LTP is designed such that theembankment fill is supported directly by the geotextilespanning between the piles. This load is transferred intothe piles by tension in the geotextile. Arching within thefill results in some reduction in vertical stress applied tothe geotextile compared with the full embankmentheight. There is no special requirement for fill properties- see figure 2.

Enhanced Arch Load Transfer PlatformThe inclusion of Tensar geogrids within granular layers hasbeen shown to increase the angle of load distributionconsiderably in comparison with the unreinforcedcondition. The geogrids interlock with the fill to mobilisethe maximum shear strength of the granular layer andenhance the load spreading mechanism.

An Enhanced Arch LTP is designed such that the majority ofthe overlying embankment load is transferred directly to thepile heads via a reinforced granular layer. This layer acts asa series of inverted pedestals above the pile heads whichjoin together to provide a continuously supported area. Thegeogrid within the granular layer combines with thepermanent support from the subgrade to support the fillbeneath the pedestals and confines the granular material,thereby resisting dilation and effectively increasing its shearstrength - see figure 1.

The fill material below the theoretical arch must bepermanently supported by the grids and the subgradewhile the arch itself must be loaded by either additional fill

Tensar International’s experienced engineers are available toprovide clients, consultants and contractors with design andconstruction advice. Designs are carried out in-house.

The services offered range from a free of charge applicationsuggestion to a full design and supply service. No liability innegligence or responsibility of any kind is accepted by TensarInternational for any project where Tensar products are not used.

2

Cut-away view of embankment supported over a Load Transfer Platform.

Figure 1: Enhanced Arch mechanism. Figure 2: Tensioned Membrane mechanism.

Tensar Basetex Tension Membrane below High Speed 1 railway embankment, UK. Anchorage for lateral Basetex layers can be achieved by wrapping around an edgethrust block.

Reinforced soil embankment constructed over piles using Tensar Basetex. Tensar Basetex Tensioned Membrane - an alternative approach to the LTP.

Tensar Technology - provenpractical solutions and theknow-how to get them builtBased on the characteristic properties of Tensargeogrids and geotextiles, Tensar Technology is widelyadopted for ground stabilisation and soilreinforcement problems, delivering real savings incost and time. We can help you apply TensarTechnology to improve the bottom line on your project.

Installing pile caps (Holland).

Installation of the Enhanced Arch Load Transfer Platform is simple and rapid.

Geogrid installation. Placing a fill layer.

4

Examples of Load Transfer Mechanismsand their applicationsEnhanced Arch Load Transfer Platform

Support of concrete ground floor slabs over soft ground. Building of supermarket (UK).

Embankment support over soft ground where only minimal settlements can be tolerated.

Highway construction adjacent to a rigid railway structure (UK).

Embankment support over soft ground where time for consolidation is eithernot available or can not be reliably determined.

Motorway toll booth plaza constructed on a Tensar LTP - the alternative tosurcharge avoiding uncertainty of predicting consolidation period (UK).

accommodate poorer quality fill if necessary.

Tensar LTPs have also been successfully used belowconcrete ground floor slabs in order to avoid designing theslabs to span between piles. However, LTPs are notsuitable for use with some ground treatment techniquessuch as vibro stone columns.

When settlement restrictions dictate that a deepfoundation solution is required to support an embankmentor ground-bearing slab, a Tensar LTP:

■ Avoids the delay required for consolidation settlement

■ Avoids the need for concrete rafts, or ground beams

■ Can be used under ground-bearing slabs to avoid or minimise bending

■ Is rapid and economical to install

■ Is a proven, reliable solution

Tensar InternationalSupport Services

Tensioned Membrane Load Transfer Platform

Basetex high-strength knitted geotextiles provide thenecessary load/strain properties when the basalreinforcement is designed to act as a Tensioned

Membrane spanning between the piles. This approach isused, for example, when there is insufficient granular fillavailable to form the LTP layer.

Constructing Load Transfer Platforms over weakground with piled foundations

For

det

ails

of

Ten

sar

wo

rksh

op

s vi

sit

ww

w.t

ensa

r-in

tern

atio

nal

.co

m

Engineers often need to construct embankments in areas whereminimal settlement can be tolerated. This is especially true whenthe serviceability of adjacent structures would be compromisedby anything other than minimal settlement. The engineer,therefore, needs to design a foundation that will provide a firmsupport without the consequential settlements andconsolidation of underlying soils.

Using a Load Transfer Platform (LTP) avoids the delay requiredfor consolidation settlement as a result of placing embankmentfill over soft, compressible soils. The Tensar Load TransferPlatform distributes embankment loads efficiently onto a seriesof piles or vibro concrete columns (VCCs) which bear on firmerstrata below. This avoids the cost of using a concrete raft. Insituations where the foundation soils can be assured to providesome permanent support to the area between the piles, then aLTP of good quality granular fill reinforced with multiple layersof Tensar grids can be used. In all other installations analternative design, using Tensar Basetex, can be employed and

Load Transfer Mechanismsor a concrete slab to ensure that the arch is permanentlylocked in compression.

As the embankment height increases the lateral forceswithin the embankment increase and these must beresisted by reinforcement anchored at the embankmentedge, to prevent the forces being imposed on the verticalpiles. Raking piles can be used as an alternative althoughfor some types of pile, e.g. vibro concrete columns, thismay be impractical.

Tensioned Membrane

Load Transfer Platform (LTP)A Tensioned Membrane LTP is designed such that theembankment fill is supported directly by the geotextilespanning between the piles. This load is transferred intothe piles by tension in the geotextile. Arching within thefill results in some reduction in vertical stress applied tothe geotextile compared with the full embankmentheight. There is no special requirement for fill properties- see figure 2.

Enhanced Arch Load Transfer PlatformThe inclusion of Tensar geogrids within granular layers hasbeen shown to increase the angle of load distributionconsiderably in comparison with the unreinforcedcondition. The geogrids interlock with the fill to mobilisethe maximum shear strength of the granular layer andenhance the load spreading mechanism.

An Enhanced Arch LTP is designed such that the majority ofthe overlying embankment load is transferred directly to thepile heads via a reinforced granular layer. This layer acts asa series of inverted pedestals above the pile heads whichjoin together to provide a continuously supported area. Thegeogrid within the granular layer combines with thepermanent support from the subgrade to support the fillbeneath the pedestals and confines the granular material,thereby resisting dilation and effectively increasing its shearstrength - see figure 1.

The fill material below the theoretical arch must bepermanently supported by the grids and the subgradewhile the arch itself must be loaded by either additional fill

Tensar International’s experienced engineers are available toprovide clients, consultants and contractors with design andconstruction advice. Designs are carried out in-house.

The services offered range from a free of charge applicationsuggestion to a full design and supply service. No liability innegligence or responsibility of any kind is accepted by TensarInternational for any project where Tensar products are not used.

2

Cut-away view of embankment supported over a Load Transfer Platform.

Figure 1: Enhanced Arch mechanism. Figure 2: Tensioned Membrane mechanism.

Tensar Basetex Tension Membrane below High Speed 1 railway embankment, UK. Anchorage for lateral Basetex layers can be achieved by wrapping around an edgethrust block.

Reinforced soil embankment constructed over piles using Tensar Basetex. Tensar Basetex Tensioned Membrane - an alternative approach to the LTP.

Tensar Technology - provenpractical solutions and theknow-how to get them builtBased on the characteristic properties of Tensargeogrids and geotextiles, Tensar Technology is widelyadopted for ground stabilisation and soilreinforcement problems, delivering real savings incost and time. We can help you apply TensarTechnology to improve the bottom line on your project.

Installing pile caps (Holland).

Installation of the Enhanced Arch Load Transfer Platform is simple and rapid.

Geogrid installation. Placing a fill layer.

4

Examples of Load Transfer Mechanismsand their applicationsEnhanced Arch Load Transfer Platform

Support of concrete ground floor slabs over soft ground. Building of supermarket (UK).

Embankment support over soft ground where only minimal settlements can be tolerated.

Highway construction adjacent to a rigid railway structure (UK).

Embankment support over soft ground where time for consolidation is eithernot available or can not be reliably determined.

Motorway toll booth plaza constructed on a Tensar LTP - the alternative tosurcharge avoiding uncertainty of predicting consolidation period (UK).

accommodate poorer quality fill if necessary.

Tensar LTPs have also been successfully used belowconcrete ground floor slabs in order to avoid designing theslabs to span between piles. However, LTPs are notsuitable for use with some ground treatment techniquessuch as vibro stone columns.

When settlement restrictions dictate that a deepfoundation solution is required to support an embankmentor ground-bearing slab, a Tensar LTP:

■ Avoids the delay required for consolidation settlement

■ Avoids the need for concrete rafts, or ground beams

■ Can be used under ground-bearing slabs to avoid or minimise bending

■ Is rapid and economical to install

■ Is a proven, reliable solution

Tensar InternationalSupport Services

Tensioned Membrane Load Transfer Platform

Basetex high-strength knitted geotextiles provide thenecessary load/strain properties when the basalreinforcement is designed to act as a Tensioned

Membrane spanning between the piles. This approach isused, for example, when there is insufficient granular fillavailable to form the LTP layer.

Constructing Load Transfer Platforms over weakground with piled foundations

For

det

ails

of

Ten

sar

wo

rksh

op

s vi

sit

ww

w.t

ensa

r-in

tern

atio

nal

.co

m

Engineers often need to construct embankments in areas whereminimal settlement can be tolerated. This is especially true whenthe serviceability of adjacent structures would be compromisedby anything other than minimal settlement. The engineer,therefore, needs to design a foundation that will provide a firmsupport without the consequential settlements andconsolidation of underlying soils.

Using a Load Transfer Platform (LTP) avoids the delay requiredfor consolidation settlement as a result of placing embankmentfill over soft, compressible soils. The Tensar Load TransferPlatform distributes embankment loads efficiently onto a seriesof piles or vibro concrete columns (VCCs) which bear on firmerstrata below. This avoids the cost of using a concrete raft. Insituations where the foundation soils can be assured to providesome permanent support to the area between the piles, then aLTP of good quality granular fill reinforced with multiple layersof Tensar grids can be used. In all other installations analternative design, using Tensar Basetex, can be employed and

Load Transfer Mechanismsor a concrete slab to ensure that the arch is permanentlylocked in compression.

As the embankment height increases the lateral forceswithin the embankment increase and these must beresisted by reinforcement anchored at the embankmentedge, to prevent the forces being imposed on the verticalpiles. Raking piles can be used as an alternative althoughfor some types of pile, e.g. vibro concrete columns, thismay be impractical.

Tensioned Membrane

Load Transfer Platform (LTP)A Tensioned Membrane LTP is designed such that theembankment fill is supported directly by the geotextilespanning between the piles. This load is transferred intothe piles by tension in the geotextile. Arching within thefill results in some reduction in vertical stress applied tothe geotextile compared with the full embankmentheight. There is no special requirement for fill properties- see figure 2.

Enhanced Arch Load Transfer PlatformThe inclusion of Tensar geogrids within granular layers hasbeen shown to increase the angle of load distributionconsiderably in comparison with the unreinforcedcondition. The geogrids interlock with the fill to mobilisethe maximum shear strength of the granular layer andenhance the load spreading mechanism.

An Enhanced Arch LTP is designed such that the majority ofthe overlying embankment load is transferred directly to thepile heads via a reinforced granular layer. This layer acts asa series of inverted pedestals above the pile heads whichjoin together to provide a continuously supported area. Thegeogrid within the granular layer combines with thepermanent support from the subgrade to support the fillbeneath the pedestals and confines the granular material,thereby resisting dilation and effectively increasing its shearstrength - see figure 1.

The fill material below the theoretical arch must bepermanently supported by the grids and the subgradewhile the arch itself must be loaded by either additional fill

Tensar International’s experienced engineers are available toprovide clients, consultants and contractors with design andconstruction advice. Designs are carried out in-house.

The services offered range from a free of charge applicationsuggestion to a full design and supply service. No liability innegligence or responsibility of any kind is accepted by TensarInternational for any project where Tensar products are not used.

2

Cut-away view of embankment supported over a Load Transfer Platform.

Figure 1: Enhanced Arch mechanism. Figure 2: Tensioned Membrane mechanism.

Tensar Basetex Tension Membrane below High Speed 1 railway embankment, UK. Anchorage for lateral Basetex layers can be achieved by wrapping around an edgethrust block.

Reinforced soil embankment constructed over piles using Tensar Basetex. Tensar Basetex Tensioned Membrane - an alternative approach to the LTP.

Tensar Technology - provenpractical solutions and theknow-how to get them builtBased on the characteristic properties of Tensargeogrids and geotextiles, Tensar Technology is widelyadopted for ground stabilisation and soilreinforcement problems, delivering real savings incost and time. We can help you apply TensarTechnology to improve the bottom line on your project.

Installing pile caps (Holland).

Installation of the Enhanced Arch Load Transfer Platform is simple and rapid.

Geogrid installation. Placing a fill layer.

4

Examples of Load Transfer Mechanismsand their applicationsEnhanced Arch Load Transfer Platform

Support of concrete ground floor slabs over soft ground. Building of supermarket (UK).

Embankment support over soft ground where only minimal settlements can be tolerated.

Highway construction adjacent to a rigid railway structure (UK).

Embankment support over soft ground where time for consolidation is eithernot available or can not be reliably determined.

Motorway toll booth plaza constructed on a Tensar LTP - the alternative tosurcharge avoiding uncertainty of predicting consolidation period (UK).

accommodate poorer quality fill if necessary.

Tensar LTPs have also been successfully used belowconcrete ground floor slabs in order to avoid designing theslabs to span between piles. However, LTPs are notsuitable for use with some ground treatment techniquessuch as vibro stone columns.

When settlement restrictions dictate that a deepfoundation solution is required to support an embankmentor ground-bearing slab, a Tensar LTP:

■ Avoids the delay required for consolidation settlement

■ Avoids the need for concrete rafts, or ground beams

■ Can be used under ground-bearing slabs to avoid or minimise bending

■ Is rapid and economical to install

■ Is a proven, reliable solution

Tensar InternationalSupport Services

Tensioned Membrane Load Transfer Platform

Basetex high-strength knitted geotextiles provide thenecessary load/strain properties when the basalreinforcement is designed to act as a Tensioned

Membrane spanning between the piles. This approach isused, for example, when there is insufficient granular fillavailable to form the LTP layer.

Constructing Load Transfer Platforms over weakground with piled foundations

A grid layer is placed. The design thickness of granular fill is placed, spread and compacted.

Details of Enhanced Arch LTP at Second Severn Crossing.

Foundations over Piles

Constructing Load TransferPlatforms over weak ground

with piled foundations

Second Severn Crossing Enhanced Arch Load Transfer Platform performance.

©Copyright Tensar International Limited

Printed August 2010 Issue 11, SDA: 583090

The information in this brochure is supplied by Tensar International free of charge. Tensar International donot assume any duty of care to you or any third party. No liability for negligence (other than for deathand personal injury) can arise from any use of or reliance on the information in this brochure or use ofany Tensar International product mentioned. Tensar International will not be liable if this brochurecontains any misrepresentation or misstatement. Determination of the suitability for any project of theinformation and any Tensar International product mentioned in it must be made by your engineer orother professional advisor who has full knowledge of the project. You, together with any such engineeror advisor, must assume all risk of loss and damage of any kind arising from use of the information or anyproduct of Tensar International other than the risk of death and personal injury. If you or any third partysubsequently purchases a product referred to in this brochure or any other Tensar International productthe entire terms of the contract of purchase and the entire obligation of Tensar International relating tothe product or arising from its use shall be as set out in Tensar International's Standard Conditions inforce at the time of purchase, a copy of which may be requested from Tensar International. Tensar andTensartech are trade marks of tensar International Limited.

Construction of an Enhanced Arch Load Transfer PlatformSmall pile caps being cast prior to constructing the Enhanced Arch Load Transfer Platform.

Once the supporting piles/VCCs have been installed thesimple construction process involves the inclusion of 2 or 3layers of Tensar geogrids in the granular layers above thesupports. Dead weight compaction of the cushion layer offill under the bottom grid, and the layer of fill between the

bottom two grids, is the only deviation from standardembankment placement and compaction operations.Overlapping, or tying, of adjacent grids provides thecontinuity required.

Second Severn Crossing, UKThe Toll Plaza area for the Second Severn Crossing in theUK was built over compressible soils supported on VCCs.Load from the embankment and pavement above wastransmitted to the VCCs using a Tensar geogrid reinforcedEnhanced Arch Load Transfer Platform (LTP). The graphssummarise the performance from monitoring this LTP.Settlement above the VCCs and mid-way between them isalmost the same, whereas stress measured at subgrade

level between the VCCs is almost zero. These results showhow well the design assumptions have been realised inpractice. The Enhanced Arch LTP has performed as a stiffraft, transmitting loads from the pavement andembankment directly to the VCCs using the excellent loadspreading capability of a granular layer reinforced withTensar biaxial geogrids.

Q 05288ISO 9001:2008

EMS 86463ISO 14001:2004

Tel: +44 (0)1254 262431

Fax: +44 (0)1254 266868

E-mail: info@tensar.co.uk

www.tensar-international.com

Tensar International Limited

Cunningham Court

Shadsworth Business Park

Blackburn BB1 2QX

United Kingdom

Contact Tensar International or your local distributor to receive furtherliterature covering Tensar products and applications.

Also available on request are product specifications, installation guidesand specification notes.

The complete range of Tensar literature consists of:

• Tensar Geosynthetics in Civil Engineering A guide to products,systems and services

• Ground Stabilisation Reinforcing unbound layers in roads andtrafficked areas

• TriAx™ A Revolution in Geogrid Technology The properties andperformance advantages of Tensar TriAx™ geogrids

• Asphalt Pavements Reinforcing asphalt layers in roads andtrafficked areas

• Tensartech Earth Retaining Systems Bridge abutments, retainingwalls and steep slopes

• Railways Mechanical stabilisation of track ballast and sub-ballast

• Foundations over Piles Constructing over weak ground withoutsettlement

• Basal Reinforcement Using Basetex high strength geotextiles

• Tensartech Geocell Mattress System

• Erosion Controlling erosion on soil and rock slopes

Your local distributor is:

A grid layer is placed. The design thickness of granular fill is placed, spread and compacted.

Details of Enhanced Arch LTP at Second Severn Crossing.

Foundations over Piles

Constructing Load TransferPlatforms over weak ground

with piled foundations

Second Severn Crossing Enhanced Arch Load Transfer Platform performance.

©Copyright Tensar International Limited

Printed August 2010 Issue 11, SDA: 583090

The information in this brochure is supplied by Tensar International free of charge. Tensar International donot assume any duty of care to you or any third party. No liability for negligence (other than for deathand personal injury) can arise from any use of or reliance on the information in this brochure or use ofany Tensar International product mentioned. Tensar International will not be liable if this brochurecontains any misrepresentation or misstatement. Determination of the suitability for any project of theinformation and any Tensar International product mentioned in it must be made by your engineer orother professional advisor who has full knowledge of the project. You, together with any such engineeror advisor, must assume all risk of loss and damage of any kind arising from use of the information or anyproduct of Tensar International other than the risk of death and personal injury. If you or any third partysubsequently purchases a product referred to in this brochure or any other Tensar International productthe entire terms of the contract of purchase and the entire obligation of Tensar International relating tothe product or arising from its use shall be as set out in Tensar International's Standard Conditions inforce at the time of purchase, a copy of which may be requested from Tensar International. Tensar andTensartech are trade marks of tensar International Limited.

Construction of an Enhanced Arch Load Transfer PlatformSmall pile caps being cast prior to constructing the Enhanced Arch Load Transfer Platform.

Once the supporting piles/VCCs have been installed thesimple construction process involves the inclusion of 2 or 3layers of Tensar geogrids in the granular layers above thesupports. Dead weight compaction of the cushion layer offill under the bottom grid, and the layer of fill between the

bottom two grids, is the only deviation from standardembankment placement and compaction operations.Overlapping, or tying, of adjacent grids provides thecontinuity required.

Second Severn Crossing, UKThe Toll Plaza area for the Second Severn Crossing in theUK was built over compressible soils supported on VCCs.Load from the embankment and pavement above wastransmitted to the VCCs using a Tensar geogrid reinforcedEnhanced Arch Load Transfer Platform (LTP). The graphssummarise the performance from monitoring this LTP.Settlement above the VCCs and mid-way between them isalmost the same, whereas stress measured at subgrade

level between the VCCs is almost zero. These results showhow well the design assumptions have been realised inpractice. The Enhanced Arch LTP has performed as a stiffraft, transmitting loads from the pavement andembankment directly to the VCCs using the excellent loadspreading capability of a granular layer reinforced withTensar biaxial geogrids.

Q 05288ISO 9001:2008

EMS 86463ISO 14001:2004

Tel: +44 (0)1254 262431

Fax: +44 (0)1254 266868

E-mail: info@tensar.co.uk

www.tensar-international.com

Tensar International Limited

Cunningham Court

Shadsworth Business Park

Blackburn BB1 2QX

United Kingdom

Contact Tensar International or your local distributor to receive furtherliterature covering Tensar products and applications.

Also available on request are product specifications, installation guidesand specification notes.

The complete range of Tensar literature consists of:

• Tensar Geosynthetics in Civil Engineering A guide to products,systems and services

• Ground Stabilisation Reinforcing unbound layers in roads andtrafficked areas

• TriAx™ A Revolution in Geogrid Technology The properties andperformance advantages of Tensar TriAx™ geogrids

• Asphalt Pavements Reinforcing asphalt layers in roads andtrafficked areas

• Tensartech Earth Retaining Systems Bridge abutments, retainingwalls and steep slopes

• Railways Mechanical stabilisation of track ballast and sub-ballast

• Foundations over Piles Constructing over weak ground withoutsettlement

• Basal Reinforcement Using Basetex high strength geotextiles

• Tensartech Geocell Mattress System

• Erosion Controlling erosion on soil and rock slopes

Your local distributor is: