Cases Icg 2010

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E n g i n e e r i n g a B e t t e r S o l u t i o n

SELECTED GLOBAL CASE HISTORIES

9º International Conferenceon Geosynthetics

Brazil 23-27 May 2010

Client:

Main contractor:

Date of construction

Designer:

Products used:

CASE HISTORYRef: UK-IT/CH/EP027 — Rev:01, July 08

MARINE EROSION PROTECTIONProduct: Ballasted Filter Mattress

MO.S.E. PROJECTVENICE, ITALY

ProblemVenice has always drawn its unique character from itssurrounding waters and it will continue to do so. BeingVenetian has always meant being part of this "watercity", living with and enjoying the positive aspects whilstconfronting specific problems.

Amongst Venice's most evident problems are thoserelated to the particular nature of the transport, thewaterborne traffic and the inconvenience caused by theacqua alta (literally, “the high water”).

Since the beginning of the 1900s, high waters havebecome more frequent and intense. The commonimage of Venice “sinking” reflects a real problem. Thelagoon area floods ever more frequently because therelationship between water and land has beenprofoundly modified, particularly during the last hundredyears.

SolutionTo provide complete protection for all built-up areas inthe lagoon from high waters of all levels, an integratedsystem of various measures (the MO.S.E. System -Modulo Sperimentale Elett romeccanico -Electromechanical Experimental Module) has beendeveloped. This includes rows of gates to be installedat the lagoon inlets able to isolate the lagoon from thesea during high tides above the established level andconstruction of breakwaters outside the inlets designedto attenuate the level of the most frequent tides.

At the heart of the system are rows of gates installedon the seabed in the three inlet channels, housed in aline of caissons. When not in operation, the gates arefull of water and rest in the caissons on the bed. Whena tide higher than the safeguard level is forecast,compressed air is introduced into the gates, expellingthe water. As the water is expelled from the gates, theyrotate around the axis of their hinge, until they emergeand block the tidal flow entering the lagoon. Oncethere, the gates remain in position until the tidal eventhas passed.

Ballasted Filter Mattress manufacturing yard

2004 / 2005

MACCAFERRI BALLASTED FILTER MATTRESS

MINISTRY OF INFRASTUCTURE, VENICE WATER AUTH.

MACCAFERRI VENICE PROJECT CONSORTIUM

TECHNITAL SpA. VERONA

BFM deployment from Bespoke barge onto Lido Bed

Introduction of airExpulsion of water

Lagoon Sea

Schematic showing gate lifting process

Officine Maccaferri S.p.A. Global HeadquartersVia JF Kennedy, 10—4069 Zola Predosa (BO) - ItalyT: (+39) 051 6436000 F: (+39) 051 236507E: [email protected]. Maccaferri.com

Bureau Veritas Certified Quality System Companywith SINCERT and UKAS accreditation.

In order to protect the gates and caissons from erosionof the lagoon bed caused by tides and vesselmovements in the lagoon, rockfill protection wasdesigned to maintain the sea bed level. Fundamentalto the success of this solution is the stability of the rockerosion protection on the sea bed. The projectdesigners required a filter layer which would not onlyguarantee the hydraulic performance required, but alsowas heavy enough to keep the filter in contact with thesea bed at all times and in all sea conditions. In thisway, instability of the seabed and potential damage tothe operation of the flood gates, is avoided.

The Maccaferri Venice Project Consortium (AdantiS.p.A, Officine Maccaferri Group and Sarti S.p.A)developed a system for the production of a uniqueBallasted Filter Mattress (BFM), and a launchingsystem to meet the client’s demands, in lengths toseamlessly protect the entire width of the lagoon inlets(from 130-200m long).

The BFM of thickness 4-5cm, consists of:• Industrial polypropylene geomat reinforced with

double twist PVC coated steel wire mesh• Granular ballast filler material• Tough geotextile filter layers, above and below the

reinforced ballast core• Riveted fixing system to connect the BFM layers

A bespoke dockside BFM assembly yard was set up. Inaddition marine work-vessels were specifically adaptedto accept and deploy the large rolls of BFM onto thesea bed.

The installation of the large mattresses (10 m wide) at adepth of 13 - 18 metres, is achieved by means of acomplex and innovative integrated system ofpackaging, transport and unrolling of the individualelements on the sea bed. Each individual mattress iswound around floating drums and delivered to a launchpontoon. Using anchored winch and winding systemson the launch pontoon, individually controlled bysatellite GPS, the rolls are deployed into the works towithin very accurate tolerances at the seabed.

The correct positioning of the mattresses is checkednot only by on-board control equipment, but also byphysical underwater inspections, to confirm thestructural soundness and positioning of the mattresses.

Throughout this demanding and unique project, TheMaccaferri Venice Project Consortium proved theirinnovation, expertise and entrepreneurialism in solvingand achieving their client’s demands to help secure theVenice World Heritage Site from future inundation.

Detail showing roll of BFM being deployed

Launch Pontoon accepting roll of BFM

Underwater inspections of installed BFM

of 2

MARIKANA PLATINUM MINE MARIKANA, NORTH WEST PROVINCE

CASE HISTORY ZAF / CH / 004: Eng - Rev. 03, Nov 2007

GEOTECHNICAL / REINFORCED SOIL WALLS Product: Terramesh™ System

Problem Part of the construction of the plant infrastructure at the new Marikana Platinum mine in the North West Province entailed providing access to the 20m high loading bin at the primary crusher. The complications associated with such a high earth retaining structure required the wall to be flexible in nature, since the wall had to accommodate: • Excessive vertical and horizontal loads (150kPa and 850kN

respectively) imposed by heavy duty Caterpillar 777 mining dump trucks.

• Dewatering of the mining area which could result in differential settlement.

• The presence of a layer of expansive materials in close proximity to the foundation of the structure.

Dowding Reynard and Associates (DRA), Plant Design and Control Engineers for Aquarius Platinum approached Maccaferri SA for design assistance. Solution A 22,5m high vertical Terramesh™ System wall was proposed. The inherent flexibility of the Terramesh™ System made it an ideal choice. The design was carried out in-house by Maccaferri’s Technical Department with the assistance of the MacStars 2000™ software package using International Design Guidelines. At the most critical section of the wall, reinforcement was provided every 0,5m in the form of 0,5m high Terramesh™ units. Additional polymer reinforcement, Terram 110/25, was installed every 1,0m vertical spacing. Reinforcement length behind the wall was in the order of 15m. To intersect the groundwater regime, a chimney drain was installed behind the reinforced zone with outlets taken through to the front face.

Client name: AQUARIUS PLATINUM Main contractor name: GRINAKER-LTA

TERRAMESH™ SYSTEM, PARAGRID™ Construction info:

Consultant:

Product used:

Construction date:

DOWDING REYNARD & ASSOCIATES

JULY 2002

OCTOBER 2002 Completion date:

Chimney Drain

Terram Grid 110/25

Pioneer LayerTerramesh™ Units

Before wall construction Date: Jul 2002

Typical Section

of 2

Date: Sep 2002

Once completed, the tallest Terramesh™ wall in Africa had a frontal face area of 1880m². A wing wall on each side of the headwall tapered off at a slope of 1:2 for an overall length of wall of 132m. The entire wall was founded on a metre thick rock pioneer layer. Only pre-approved selected soil was used for the backfill operation and compacted to 98% MOD AASHTO. Quality control on site was strictly monitored. Benefits • The modular Terramesh™ System units were manufactured

with the correct reinforcement length before delivery to site. This allowed for quick and easy installation by the contractor.

• The inherent flexibility of the Terramesh™ System allows

for settlement and consolidation without excessive deformation to the reinforced wall structure and loss of function. Expected settlement during the life of structure around 300mm.

• Terramesh™ offers 47kN/m tensile resistance at only 2%.

Any strain or movement within the soil is taken up instantaneously by the reinforcement.

• The PVC coated mesh ensures that the long term design

strength of the reinforcement is not compromised by chemical, biological or environmental degradation.

• On-site soil materials were used for the structural backfill,

reducing the overall cost of the project. • Maccaferri offered professional indemnity on the design. A

full time supervisor strictly monitored quality control of materials and compaction.

Date: Sep 2002 During construction

During construction

• Trainers were made available to assist the contractor in achieving a high standard of rock packing and impart the necessary skills to the labourers.

• The project generated much needed employment. Eighty

labourers were used for the packing of the front face, alleviating the poverty and contributing financially to the local economy of the area.

Maccaferri SA (Pty) Ltd reserves the right to amend product specifications without notice and specifiers are requested to check as to the validity of the specifications they are using.

www.maccaferri.co.za

HEAD OFFICE - DURBAN, SOUTH AFRICA P O Box 15777, Westmead, 3608 Tel: +27-31-700 8456 Fax: +27-31-700 8469 e-mail: [email protected] JOHANNESBURG, SOUTH AFRICA P O Box 2285, North Riding, 2162 Tel: +27-11-704 0160 Fax: +27-11-704 0159 e-mail: [email protected] CAPE TOWN, SOUTH AFRICA P O Box 22150, Fish Hoek, 7974 Tel: +27-21-702 1416 Fax: +27-21-702 2977 e-mail: [email protected] MADAGASCAR BP 168 Antananarivo 101, Madagascar Tel: +261-20-22-231 02 Fax: +261-20-22-553 90 e-mail: [email protected]

Maccaferri SA (Pty) Ltd

BENTO DE ABREU SOCCER STADIUM

Solution: DRAINAGEProduct: MacDrain® TD

During the work

Solution description:

After studying several kinds of trench drain solutions, it opted to use the drainage system constituted by MacDrain® geo-composite drainage, because of their technical properties and ease constructive.

This new drainage system has been installed in just 4 days and to avoid any installation damage in the lawn, it has been used a mechanical trencher equipment to get sufficient width to include correctly the geocomposite drain and geopipe.

Customer:

MARÍLIA ATLÉTICO CLUBE

Responsible for building:

Used products:

GRAMADOS MARÍLIA (GRAMAR)

Problem description:

The Bento de Abreu Soccer Stadium located in Marilia City - São Paulo - Brazil is the place where one of the most important soccer teams from Brazil trains your soccer team, the Marilia Atletico Club.

This Stadium has a soccer field that was presenting deep functionality troubles during the rainy period due to the drainage precarious system.

It was necessary a type of solution that allowed a quick and efficient installation and which did not interfere in schedule of the soccer championship.

BRAZIL, MARÍLIA - SP

Before the work

During the work

1.380m - MacDrain® TD (0,90m)1.130m - Tube 4’’

CASE HISTORYRev: 00, Issue Date 24/08/2005

Construction period:Starting:Ending:

January/2005January/2005

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Finished work

www.maccaferri.com.br

Illustrative Schemes

During the work

Finished work

During the work

CASE HISTORYRef: UK / TR / CH / SR028 - Rev: 01, July 08

SLOPE REINFORCEMENT IN LANDFILLSProduct: Paragrid 100/05 & 50/05, Paralink 700, 500 & 400, Terram 1B, MaclineGCL NL10, Terram 1000 & 4500, 2mm Macline SHE

AYDIN UNCONTROLLED DISPOSAL SITEAYDIN, TURKEY

ProblemAs part of the design of the new controlled disposal sitein the Municipality of Aydin (in southern Turkey, nearthe ancient ruins of Ephesus) it was necessary todesign - in addition to the bottom barrier system of thedisposal site itself - two structures which acted ascontainment dams for the first and second cells. Thegorge had to be divided into two independent cells; thefirst cell was constructed at the same time as theformation of the containment structures whilst thesecond cell will be waterproofed as soon as the firstone has been completed and made safe. The cells arevery deep so it has been necessary to build a series ofaccess roads within the disposal site and forconnection to the town of Aydin.

SolutionThe solution developed by the designers has beenbased on the techniques and construction practiceswhich have been in use for some time in Europe withregard to the barrier system package and considerableuse has been made of geogrids for the formation of thecontainment structures for the two cells and for theembankments forming the site roads. The adoption ofvarious strengths of geogrids has enabled use of thesoil present on site and the grading of slopes toinconceivable angles for a loose material, therebyachieving considerable reductions, both in terms ofcosts and material volumes. The bottom barrier systemuses a 2 mm HDPE membrane (Macline SHE) restingon a layer of low permeability clay covered by ageotextile protection layer (Terram 4500), used incombination with a bed of sand and a mineral drainagelayer in which a mesh of drainage pipes has beenincorporated. The clay layer has been replaced on thesteep slopes by a bentonite geocomposite laminate(Macline GCL NL10), whilst a geogrid-geotextile non-woven geocomposite (Terram 1B) has been used to

Paragrid 100/5 110,000m2, Paragrid 50/05 5,000 m2, Paralink 7005,000m2, Paralink 500 5,000 m2, Paralink 400 32,000m2, MaclineGCL N10 44,000m2, Terram 1B 30,000m2, Terram 1000 26,000 m2,Terram 4500 10,500m2, 2mm Macline SHE 45,000m2

Construction date:

Designer:

Products used:

November 2006 — April 2007

SERDAR Engineering (Ankara)

Client name:MUNICPALITY OF AYDINMain contractor name:CENGI CONSTRUCTION SpP (Ankara)

During construction Date: November 2006

Project layout — reinforced earth works shown in brown

During construction (future cell containment wall) After construction (future cell 2 containment wall)

After construction (cell 1)

Date: November 2006

Typical design section — highest section

The stability of the structures (bothinternally and globally) has been checkedusing specific software called MACSTARS(Maccaferri Stability Analysis ReinforcedSlopes). This enables the use of differenttypes of reinforcement elements (syntheticand metal), with different mechanicalstrengths and with any geometricalconfiguration, thereby simulating thevarious types of external loads applied tothe structure (point loads and distributedforces, seismic forces, etc.).The diagramalongside shows the output for the externalstability checks carried out for a section ofthe embankments, in which the slip circlesare highlighted with different coloursdepending on the safety factor. Thisdiagram enables a fast visualisation of thecritical slip surfaces and becomes apowerful and effective tool for design andcontrol.

Post construction, North bound off-slip

Spring 2007 — Installation of bottom barrier system

Puncture-resistant drainage geocomposite Terram B1

Granular drainage material

Non-woven geotextileTerram 4500 with sand

1m clay layer2mm HDPE geomembrane Macline SHEBentonite geocomposite laminate Macline GCL NL 10



CANRASH’S SLOPE

Solution: EROSION CONTROL Product: MacMat® L

During the work

Solution description:

Maccaferri introduced MacMat Geomat as solution for the pro-tection of slope, respecting the hydrological and topographical conditions of the location. The technical responsible for this work a counseled CMA during the design period; also propose other bioengineering solutions as alternative to MacMat geomat, be-cause until that time it was believed that the two were technically similar.

One year latter, it was possible to check the results both alterna-tive. The MacMat geomat had a better revegetated behavior on the tested area than the Biomat blanket. This occurred because the erodibility level in this place is very high for the erosion control blanket solution.

Customer:CIA MRA ANTAMINA

Used products

Problem description:

In July 2001 the environment department of the Antamina Mining Company (CMA) had to solve an erosion serious problem, which it could pledge companies’ mining economy.

On the road to access Antamina mine, Conococha Yanacancha Road, which the Canrash’s lake is located, was affected by the construction of the roadway. Soon after its construction, the lake had a fast increase in the quantity of sediment concentration, leading damages to fauna y flora in this place.

CMA noted that the main source of sediments was an adjacent slope. This slope had several points without vegetation and eroded material was transported until the lake during the rainy periods.

To decrease the sediments dragged by the rain, it decided revegetated the slope, and other procedures for controlling sediment.

PERU, ANCASH

During the work

During the work

35.000m2 - MacMat® L

CASE HISTORYRev: 00, Issue Date 09/05/2006

Construction period:Starting:Ending:

August/2001September/2001

Responsible for building:CIA MRA ANTAMINA

Finished work

www.maccaferri.com.br

Illustrative Schemes

Finished work

Finished work

Finished work

Client:

Main contractor:


Consultant:

Products used:

CASE HISTORYRef: UK / IN / CH / RS045 — Rev:01, July 08

RETAINING STRUCTURESProduct: MACRES VERTICAL CONCRETE PANEL WALL SYSTEM

JAIPUR-KISHANGARH EXPRESSWAYRAJASTHAN, INDIA

ProblemDuring the construction of Jaipur-KishangarhExpressway, National Highway Authority (NHAI)identified that at busy intersections 3 flyovers had to beconstructed which required 12 wing and approach wallsand 6 headwalls. NHAI decided to construct verticalwalls where the maximum height was up to 12.2metres. The embedment depth into the silty sands atfoundation level would need to be about 3m belowground level in some stretches, and avoided extensivefoundation improvement schemes.

Reinforced soil walls were selected as the solutioninstead of conventional reinforced concrete solutionsdue to the cost of the conventional solution was veryhigh and the authorities wanted to have a system whichwas flexible and simple to construct. The structure hadto withstand seismic and highway loadings.

SolutionThe Maccaferri MacRES Vertical Reinforced Earth WallSystem with concrete panels as a facia and Parawebhigh strength polymeric soil reinforcement, wasselected as the optimum solution for the aboveproblem. Furthermore, the client wished to reuse thesite won marginal fills, which precluded the use oftraditional steel strip reinforcement. Therefore the highstrength polymer reinforcement Paraweb was ideallysuited.

Paraweb is a flat strip reinforcement productconstructed from high tenacity polyester fibres,encased within a tough polyethylene sheath. Thesestrips are placed within compacted backfill, reinforcingit and are connected to concrete fascia panels.

Paraweb was one of the first ever soil reinforcingmaterials in the world and has been in use in theseapplications since 1977. Each strip has a tensilestrength of between 30kN and 100kN.

MAY - DECEMBER 2004

PARAWEB & GEOTEXTILE, WALL AREA 30,000M2

NATIONAL HIGHWAYS AUTHORITY OF INDIA

GVK EXPRESSWAY, L&T

BCEOM, LASA

Construction of levelling foundation pads

Concrete panels ready for construction

Laying of Paraweb



Installing concrete fascia panels

Construction phase complete

The connection between the panels & facia is achievedby galvanized toggles and reinforcement loops.Structural backfill with an angle of internal friction of 30degrees was compacted upon the Parawebreinforcement.

30,000m2 of walls were constructed in 3 months to amaximum height of 12m high.

The project was completed 3 months ahead ofschedule and a delighted client has been pleased withthe way the MacRES structure has already weathered3 monsoons.

Paraweb placement

Client:

Main contractor:


Designer:

Products used:

CASE HISTORYRef: UK / CH / BP013 — Rev:02, November 08

BASAL PLATFORMSProduct: ParaLink, ParaGrid

A1041 CARLTON BRIDGENORTH YORKSHIRE, UK

Problem

The A1041 links the villages of Snaith and Carlton in NorthYorkshire. The River Aire separates the two communities. Theexisting road crosses the river via a steel truss bridge, withthe approaches upon concrete viaducts. The viaducts neededto be replaced with embankments whilst the original steelbridge was being retained and strengthened.

As the embankments were constructed over soft ground, apiled basal reinforced load transfer platform (BRP) would berequired to support the approach embankments on either sideof the River.

Solution

To reduce the embankment load and footprint of theembankment, main contractor Costain Ltd opted for alightweight embankment fill (PFA) to reduce the pile size andsteepened the embankment side slopes by the use ofParaGrid geogrid reinforcement. This approach reduced thesize and capacity of the piles as well as the total number ofpiles in the embankment.

Based on previous successful experience in similarapplications, Maccaferri offered its Strip System solution. The‘Strip System’ differs from traditional BRP systems in thatinstead of reinforcing the entire footprint of the embankmentwith geogrid, the design is optimized to the extent that geogridis only placed where it is needed. Using 3D finite elementanalysis, it can be shown that geogrid strips need only belocated only along the line of, and between, the pile capswhere the load transfer requirement is greatest. This reducesthe amount of geogrid required as well as saving onembankment construction time.

This methodology was used to specify materials for theCarlton Bridge embankments and verified using VIPS, a finiteelement computer programme from Visage.

HIGHWAYS AGENCY

COSTAIN

PARALINK, PARAGRID

HALCROW GROUP LTD.

Monitoring gauges used in embankmentOCTOBER 2001

Pile cap detail showing Paralink in place

During construction of the approach ramp to the bridge



During construction

During construction

Installation of monitoring gauges

ParaLink strips are high strength, high modulus polyesterbased geogrid strips with tough polyethylene sheathing. Thisenables Paralink to be placed directly on the pile caps withoutconcerns of alkalinity degradation or installation damage dueto the rough edges of the pile caps. Available in a range ofstrengths from 100kN/m up to 1250kN/m and custom-madeto meet precise design specifications, ParaLink offerssuperior uni-directional strength and is BBA Roads andBridges certified for a design life of 120 years.

To reinforce the side slopes of the embankment, makingthem stand at 60deg from horizontal, Maccaferri specifiedParaGrid geogrid soil reinforcement; a similar product offeringbi-directional strength, to reinforce the slopes to theembankment. ParaGrid is BBA Roads and Bridges Certifiedand is used for structural applications where long-term designlife (60-120 years) is required.

Halcrow requested instrumentation of the sub-soil and strainreadings from the geogrids to ensure that their performancespecification was being met.

Soil instruments Ltd installed profiles gauges, piezometers,extensometers and inclinometers under each embankmentwith strain gauges to the ParaLink strips. The strain gaugesused are of the type normally used on the fuselage of aircraftto measure strain within the shell of aircraft bodies and havebeen set to the anticipated range of strains within the geogrid.In the past, performance specifications for this type ofstructure gave not been verified, other than in the ultimatesurface settlement.

Client:

Main contractor:


Designer:

Products used:

CASE HISTORYRef: CH / UK / RS021 — Rev:01, Nov 09

REINFORCED SOIL RETAINING WALLS & ROCKFALL PROTECTIONProduct: Terramesh System, Paralink 300, Steelgrid MO, Macmat R,

Rockfall Barrier CTR 05-07-B

MIXED RSS FOR THE RRESHEN-KALIMASH HIGHWAYALBANIA

ProblemWhat is thought to be one of the tallest reinforced earthstructures ever to be built in Europe forms part of thenew Rreshen to Kalimash motorway.

The 103 km long motorway is a key connectionbetween Durres Port, Albania's primary harbour on theAdriatic Sea and Kosovo. Journey times of between sixand ten hours will be reduced to two by this new roadand the new route will serve to stimulate the economyin Albania's North Eastern region.

The 61km long central section of the route travelsthrough some of the most isolated areas of the country.It includes dual carriageways of 2 x 3.75m lanes,supplemented with 2.0m emergency shoulder lanesthrough the challenging topography of the mountainousterrain at an altitude over 1,000m. This section of theworks ultimately included 29 bridges (4.4km totallength), 5.5km of tunnelling and 70 retaining wallstotalling 6.4km in length.

Due to the mountainous topography of the area, manysections of the motorway run alternately through largesteep embankment fill sections and slope cuts, with soilreinforcement, rock-fall protection, erosion control andre-vegetation measures required. The availability oflarge quantities of rock fills generated by the slopeexcavations made the choice of embankment fills amore cost effective alternative to the construction ofviaducts.

Of the 70 retaining walls required, those up to 15m highwere constructed of concrete. However, the 30 wallsover 15m high were designed as reinforced soilstructures to re-use site won fill and reduce the visualimpact.

GOVERNMENT OF ALBANIA

BECHTEL-ENKA JOINT VENTURE

TERRAMESH, PARALINK, ROCKFALL BARRIERS

ALBANIA DRAHT / MACCAFERRI

Laying Paralink primary reinforcement

JUNE 2008 - SEPTEMBER 2009

The first courses of the tallest wall being constructed

BBA Certified Paralink can accommodate many fill types

The tallest wall nearing completion

SolutionBechtel-Enka brought in geotechnical specialists,Officine Maccaferri (the Italian parent company ofOxford based Maccaferri Ltd) in a partnershiparrangement to provide engineering design solutionsfor the walls.

Maccaferri’s responsibility encompassed the designassistance, structural calculations and constructiondrawings for the 30 walls. For 20 of the walls,Maccaferri also provided supervision and constructionmanagement through its local partner Albania Draht.

The 30 composite reinforced soil structures have a totalfacing surface area of more than 35,000 m2, with themaximum wall overall height of 40 m. The walls, wherea steep (84°) facing was required, have beenconstructed using a hybrid reinforced soil system,combining two Maccaferri products;• Terramesh System, a double-twisted steel wire

mesh unit which forms structures with theaesthetics of gabions but with the reassurance ofsoil reinforcement.

• Paralink 300, a high strength polyester geogrid(primary reinforcement).

The Paralink was spaced at 1 or 2m vertical centresdepending upon the design requirement. These wallsare amongst the highest of their type constructedanywhere in the world.

Ground conditions on the site varied from rock that wasin parts competent to frequently shattered and fracturedin others. In areas where the rock is at its mostcompetent, the slopes were simply cut back to nearvertical with rock ditches created to catch fallingmaterial.

On the slopes up to 45o angle above some of the walls,rockfall protection, erosion control and re-vegetationmeasures were installed to protect the motorway belowand to promote rapid establishment of stabilising,vegetative cover. Maccaferri Macmat R1 6822 GN wasused to stabilise the slope face and reinforcevegetation.

On slopes where rocks could detach and fall onto thehighway, SteelGrid MO 150, high tensile strengthrockfall mitigation mesh was installed in conjunctionwith anchors and rock bolts to limit rock detachmentand contain friable rock slopes. Finally, where largerocks were prone to detachment and meshing was notfeasible, Maccaferri’s 500 kJ high resistance rockfallbarrier (CTR 05-07-B) were installed as rockfallprotection. Specialist design assistance was againprovided by Maccaferri.

Maccaferri Terramesh is a reinforced soil system forstabilising steep and near vertical slopes. A Terrameshunit comprises a continuous horizontal panel of wovenwire steel mesh geogrid with a integral gabion fasciaunit. The fascia unit is filled with hard durable rock-fill,

Final design of the 40 m high wall section

The tallest wall during construction



identical to a gabion, and the geogrid tail is thensandwiched between layers of compacted backfillmaterial, thereby reinforcing it. Having the geogrid tailintegral with the fascia element removes the need forany on-site connection or pinning where errors duringinstallation could occur due to incomplete connection,or reduced pinning frequency. Terramesh is rapid toconstruct, and can even reuse site won materials whensuitable.

Consecutive layers of Terramesh units are thenconstructed to form reinforced soil retaining structuresof almost any height when used in conjunction withhigh strength Paralink geogrids.

Paralink is a unique high strength uniaxial geogrid usedin basal platforms over piles, soft ground or over voidscaused by mine-workings, caves and so on. Availablein strengths up to 1350kN in a single layer of geogrid,Paralink consists of polyester reinforcement yarnsencapsulated within a tough polyethylene sheath.Having been in use since the late 1970’s, Paralink hasgreat pedigree in the geosynthetics market.

Maccaferri Terramesh and Paralink are BBA Roadsand Bridges certified.

The successful Bechtel-Enka/Maccaferri partnershiparrangement is typical of the projects Maccaferri isincreasingly undertaking with complex internationalprojects, reinforcing their global presence, capabilitiesand experience.

Pic.9 - View of “area d’intervento 2”Steelgrid being lifted into position ready for fixing

Overview of the highest wall nearing completion

High strength Steelgrid being installed on rockface

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