www. ma c c a f e r r i .c o m Engi neer i ng a Bet t er Sol ut i on SELECTED GLOBAL CASE HISTORIES 9º International Conference on Geosynthetics Brazil 23-27 May 2010 Client: Main contractor: Date of construction Designer: Products used: CASE HISTORY Ref: UK-IT/CH/EP027 — Rev:01, July 08 MARINE EROSION PROTECTION Product: Ball asted Filter Mattress MO.S.E. PROJECT VENICE, ITALY Problem Venice has always drawn its unique character fromits surrounding waters and it will continue to do so. Being Venetian has always meant being part of this "water city", living with and enjoying the positive aspects whilst confronting specific problems. Amongst Venice's most evident problems are those related to the particular nature of the transport, the waterborne traffic and the inconvenience caused by the acqua alta (literally, “the high water”). Since the beginning of the 1900s, high waters have become more frequent and intense. The common image of Venice “sinking” reflects a real problem. The lagoon area floods ever more frequently because the relationship between water and land has been profoundlymodified, particularlyduringthe last hundred years. Solution To provide complete protection for all built-up areas in the lagoon fromhigh waters of all levels, an integrated system of various measures (the MO.S.E. System - Modulo Sperimentale Elettromeccanico - Electromechanical Experimental Module) has been developed. This includes rows of gates to be installed at the lagoon inlets able to isolate the lagoon fromthe sea during high tides above the established level and construction of breakwaters outside the inlets designed to attenuate the level of the most frequent tides. At the heart of the system are rows of gates installed on the seabed in the three inlet channels, housed in a line of caissons. When not in operation, the gates are full of water and rest in the caissons on the bed. When a tide higher than the safeguard level is forecast, compressed air is introduced into the gates, expelling the water. As the water is expelled fromthe gates, they rotate around the axis of their hinge, until they emerge and block the tidal flow entering the lagoon. Once there, the gates remain in position until the tidal event has passed. Ball ast ed Filt er Mattress manufacturi ng yard 2004 / 2005 MACCAFERRI BALLASTEDFILTER MATTRESS MINISTRY OF INFRASTUCTURE, VENICE WATER AUTH. MACCAFERRI VENICE PROJ ECT CONSORTIUM TECHNITAL SpA. VERONA BFM deployment from Bespoke barge onto Li do Bed Introduction of air Expulsion of water Lagoon Sea Schemati c showi ng gat e l ifti ng process Offici ne Maccaferri S.p.A. Gl obal Headquarters ViaJ F Kennedy, 10—4069 Zola Predosa (BO) - Italy T: (+39) 051 6436000 F: (+39) 051 236507 E:
[email protected] www. Maccaf erri.com Bureau Veritas Certified Quality System Company with SINCERT and UKAS accreditation. In order to protect the gates and caissons fromerosion of the lagoon bed caused by tides and vessel movements in the lagoon, rockfill protection was designed to maintain the sea bed level. Fundamental to the success of this solution is the stability of the rock erosion protection on the sea bed. The project designers required a filter layer which would not only guarantee the hydraulic performance required, but also was heavy enough to keep the filter in contact with the sea bed at all times and in all sea conditions. In this way, instability of the seabed and potential damage to the operation of the flood gates, is avoided. The Maccaferri Venice Project Consortium (Adanti S.p.A, Officine Maccaferri Group and Sarti S.p.A) developed a system for the production of a unique Ballasted Filter Mattress (BFM), and a launching system to meet the client’s demands, in lengths to seamlessly protect the entire width of the lagoon inlets (from130-200mlong). The BFM of thickness 4-5cm, consists of: • Industrial polypropylene geomat reinforced with double twist PVC coatedsteel wire mesh • Granular ballast filler material • Tough geotextile filter layers, above and belowthe reinforced ballast core • Rivetedfixing system to connect the BFMlayers A bespoke dockside BFM assembly yard was set up. In addition marine work-vessels were specifically adapted to accept and deploy the large rolls of BFM onto the sea bed. The installation of the large mattresses (10 mwide) at a depth of 13 - 18 metres, is achieved by means of a complex and innovative integrated system of packaging, transport and unrolling of the individual elements on the sea bed. Each individual mattress is wound around floating drums and delivered to a launch pontoon. Using anchored winch and winding systems on the launch pontoon, individually controlled by satellite GPS, the rolls are deployed into the works to withinveryaccurate tolerances at the seabed. The correct positioning of the mattresses is checked not only by on-board control equipment, but also by physical underwater inspections, to confirm the structural soundness and positioning of the mattresses. Throughout this demanding and unique project, The Maccaferri Venice Project Consortium proved their innovation, expertise and entrepreneurialismin solving and achieving their client’s demands to help secure the VeniceWorldHeritage Site fromfuture inundation. Detai l showi ng roll of BFM being depl oyed Launch Pontoon accepting roll of BFM Underwater inspect ions of inst all ed BFM Page 1 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 TerramGrid 110/25 Pioneer Layer Terramesh™ Units Before wall construction Date: Jul 2002 Typical Section Page 2 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:
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[email protected] Maccaferri SA (Pty) Ltd BENTO DE ABREU SOCCER STADIUM Solution: DRAINAGE Product: 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 HISTORY Rev: 00, Issue Date 24/08/2005 Construction period: Starting: Ending: January/2005 January/2005 M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % M a c D r a in ® T D T U B E Ø 1 0 0 m m ( P E R F . ) i= 0 , 5 0 % Finished work www.maccaferri.com.br Illustrative Schemes During the work Finished work During the work CASE HISTORY Ref: UK / TR / CH / SR028 - Rev: 01, July 08 SLOPE REINFORCEMENT IN LANDFILLS Product: Paragrid 100/05 & 50/05, Paralink 700, 500 & 400, Terram1B, Macline GCL NL10, Terram1000 &4500, 2mmMacline SHE AYDIN UNCONTROLLED DISPOSAL SITE AYDIN, TURKEY Problem As part of the design of the newcontrolled disposal site in the Municipality of Aydin (in southern Turkey, near the ancient ruins of Ephesus) it was necessary to design - in addition to the bottombarrier systemof the disposal site itself - two structures which acted as containment dams for the first and second cells. The gorge had to be divided into two independent cells; the first cell was constructed at the same time as the formation of the containment structures whilst the second cell will be waterproofed as soon as the first one has been completed and made safe. The cells are very deep so it has been necessary to build a series of access roads within the disposal site and for connection to the town of Aydin. Solution The solution developed by the designers has been based on the techniques and construction practices which have been in use for some time in Europe with regard to the barrier systempackage and considerable use has been made of geogrids for the formation of the containment structures for the two cells and for the embankments forming the site roads. The adoption of various strengths of geogrids has enabled use of the soil present on site and the grading of slopes to inconceivable angles for a loose material, thereby achieving considerable reductions, both in terms of costs and material volumes. The bottombarrier system uses a 2 mmHDPE membrane (Macline SHE) resting on a layer of low permeability clay covered by a geotextile protection layer (Terram 4500), used in combination with a bed of sand and a mineral drainage layer in which a mesh of drainage pipes has been incorporated. The clay layer has been replaced on the steep slopes by a bentonite geocomposite laminate (Macline GCL NL10), whilst a geogrid-geotextile non- woven geocomposite (Terram 1B) has been used to Paragrid 100/5110,000m 2 , Paragrid 50/05 5,000 m 2 , Paralink 700 5,000m 2 , Paralink 500 5,000 m 2 , Paralink 40032,000m 2 , Macline GCL N10 44,000m 2 , Terram1B 30,000m 2 , Terram1000 26,000 m 2 , Terram4500 10,500m 2 , 2mmMacline SHE 45,000m 2 Construction date: Designer: Products used: November 2006 — April 2007 SERDAR Engineering (Ankara) Client name: MUNICPALITY OF AYDIN Main contractor name: CENGI CONSTRUCTION SpP (Ankara) Duri ng constructi on Dat e: November 2006 Proj ect l ayout — reinforced earth works shown i n brown Duri ng constructi on (f uture cel l cont ainment wall) After construct ion (fut ure cell 2 cont ai nment wall ) After construct ion (cell 1) Dat e: November 2006 Typical desi gn secti on — hi ghest sect ion The stability of the structures (both internally and globally) has been checked using specific software called MACSTARS (Maccaferri Stability Analysis Reinforced Slopes). This enables the use of different types of reinforcement elements (synthetic and metal), with different mechanical strengths and with any geometrical configuration, thereby simulating the various types of external loads applied to the structure (point loads and distributed forces, seismic forces, etc.).The diagram alongside shows the output for the external stability checks carried out for a section of the embankments, in which the slip circles are highlighted with different colours depending on the safety factor. This diagram enables a fast visualisation of the critical slip surfaces and becomes a powerful and effective tool for design and control. Post construction, North bound off-sli p Spring 2007 — Inst all ati on of bottom barri er system Puncture-resistant drainage geocomposite TerramB1 Granular drainagematerial Non-woven geotextile Terram4500withsand 1mclaylayer 2mmHDPE geomembrane Macline SHE Bentonite geocomposite laminate Macline GCL NL 10 Offici ne Maccaferri S.p.A. Gl obal Headquarters ViaJ F Kennedy, 10—4069 Zola Predosa (BO) - Italy T: (+39) 051 6436000 F: (+39) 051 236507 E:
[email protected] www. Maccaf erri.com Bureau Veritas Certified Quality System Company with SINCERT and UKAS accreditation. 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 reve- getated the slope, and other procedures for controlling sediment. PERU, ANCASH During the work During the work 35.000m 2 - MacMat ® L CASE HISTORY Rev: 00, Issue Date 09/05/2006 Construction period: Starting: Ending: August/2001 September/2001 Responsible for building: CIA MRA ANTAMINA Finished work www.maccaferri.com.br Illustrative Schemes Finished work Finished work Finished work Client: Main contractor: Date of construction Consultant: Products used: CASE HISTORY Ref: UK / IN / CH / RS045 — Rev:01, July 08 RETAINING STRUCTURES Product: MACRESVERTICAL CONCRETE PANEL WALL SYSTEM JAIPUR-KISHANGARH EXPRESSWAY RAJ ASTHAN, INDIA Problem During the construction of J aipur-Kishangarh Expressway, National Highway Authority (NHAI) identified that at busy intersections 3 flyovers had to be constructed which required 12 wing and approach walls and 6 headwalls. NHAI decided to construct vertical walls where the maximum height was up to 12.2 metres. The embedment depth into the silty sands at foundation level would need to be about 3m below ground level in some stretches, and avoided extensive foundation improvement schemes. Reinforced soil walls were selected as the solution instead of conventional reinforced concrete solutions due to the cost of the conventional solution was very high and the authorities wanted to have a systemwhich was flexible and simple to construct. The structure had to withstand seismic and highway loadings. Solution The Maccaferri MacRES Vertical Reinforced Earth Wall System with concrete panels as a facia and Paraweb high strength polymeric soil reinforcement, was selected as the optimum solution for the above problem. Furthermore, the client wished to reuse the site won marginal fills, which precluded the use of traditional steel strip reinforcement. Therefore the high strength polymer reinforcement Paraweb was ideally suited. Paraweb is a flat strip reinforcement product constructed from high tenacity polyester fibres, encased within a tough polyethylene sheath. These strips are placed within compacted backfill, reinforcing it and are connected to concrete fascia panels. Paraweb was one of the first ever soil reinforcing materials in the world and has been in use in these applications since 1977. Each strip has a tensile strength of between 30kN and 100kN. MAY - DECEMBER 2004 PARAWEB &GEOTEXTILE, WALL AREA 30,000M 2 NATIONAL HIGHWAYS AUTHORITY OF INDIA GVK EXPRESSWAY, L&T BCEOM, LASA Construct ion of level ling foundati on pads Concrete panels ready for construct ion Laying of Paraweb Offici ne Maccaferri S.p.A. Gl obal Headquarters ViaJ F Kennedy, 10—4069 Zola Predosa (BO) - Italy T: (+39) 051 6436000 F: (+39) 051 236507 E:
[email protected] www. Maccaf erri.com Bureau Veritas Certified Quality System Company with SINCERT and UKAS accreditation. Inst all ing concrete fascia panels Construct ion phase compl et e The connection between the panels &facia is achieved by galvanized toggles and reinforcement loops. Structural backfill with an angle of internal friction of 30 degrees was compacted upon the Paraweb reinforcement. 30,000m2 of walls were constructed in 3 months to a maximumheight of 12mhigh. The project was completed 3 months ahead of schedule and a delighted client has been pleased with the way the MacRES structure has already weathered 3 monsoons. Paraweb pl acement Client: Main contractor: Date of construction Designer: Products used: CASE HISTORY Ref: UK / CH / BP013 — Rev:02, November 08 BASAL PLATFORMS Product: ParaLink, ParaGrid A1041 CARLTON BRIDGE NORTH YORKSHIRE, UK Probl em The A1041 links the villages of Snaith and Carlton in North Yorkshire. The River Aire separates the two communities. The existing road crosses the river via a steel truss bridge, with the approaches upon concrete viaducts. The viaducts needed to be replaced with embankments whilst the original steel bridge was beingretained and strengthened. As the embankments were constructed over soft ground, a piled basal reinforced load transfer platform (BRP) would be required to support the approach embankments on either side of the River. Sol uti on To reduce the embankment load and footprint of the embankment, main contractor Costain Ltd opted for a lightweight embankment fill (PFA) to reduce the pile size and steepened the embankment side slopes by the use of ParaGrid geogrid reinforcement. This approach reduced the size and capacity of the piles as well as the total number of piles inthe embankment. Based on previous successful experience in similar applications, Maccaferri offered its Strip Systemsolution. The ‘Strip System’ differs from traditional BRP systems in that instead of reinforcing the entire footprint of the embankment withgeogrid, the designis optimized to the extent that geogrid is only placed where it is needed. Using 3D finite element analysis, it can be shown that geogrid strips need only be located only along the line of, and between, the pile caps where the load transfer requirement is greatest. This reduces the amount of geogrid required as well as saving on embankment construction time. This methodology was used to specify materials for the Carlton Bridge embankments and verified using VIPS, a finite element computer programmefromVisage. HIGHWAYS AGENCY COSTAIN PARALINK, PARAGRID HALCROWGROUP LTD. Monitoring gauges used in embankment OCTOBER 2001 Pi le cap det ail showing Paral ink i n pl ace During construct ion of the approach ramp to the bri dge Offici ne Maccaferri S.p.A. Gl obal Headquarters ViaJ F Kennedy, 10—4069 Zola Predosa (BO) - Italy T: (+39) 051 6436000 F: (+39) 051 236507 E:
[email protected] www. Maccaf erri.com Bureau Veritas Certified Quality System Company with SINCERT and UKAS accreditation. During construct ion During construct ion Inst all ati on of monitori ng gauges ParaLink strips are high strength, high modulus polyester based geogrid strips with tough polyethylene sheathing. This enables Paralink to be placed directly on the pile caps without concerns of alkalinity degradation or installation damage due to the rough edges of the pile caps. Available in a range of strengths from 100kN/m up to 1250kN/m and custom-made to meet precise design specifications, ParaLink offers superior uni-directional strength and is BBA Roads and Bridges certified for a designlife of 120years. To reinforce the side slopes of the embankment, making them stand at 60deg from horizontal, Maccaferri specified ParaGrid geogrid soil reinforcement; a similar product offering bi-directional strength, to reinforce the slopes to the embankment. ParaGrid is BBA Roads and Bridges Certified and is used for structural applications where long-termdesign life (60-120years) is required. Halcrow requested instrumentation of the sub-soil and strain readings from the geogrids to ensure that their performance specification was beingmet. Soil instruments Ltd installed profiles gauges, piezometers, extensometers and inclinometers under each embankment with strain gauges to the ParaLink strips. The strain gauges used are of the type normally used on the fuselage of aircraft to measure strain within the shell of aircraft bodies and have been set to the anticipated range of strains withinthe geogrid. In the past, performance specifications for this type of structure gave not been verified, other than in the ultimate surface settlement. Client: Main contractor: Date of construction Designer: Products used: CASE HISTORY Ref: CH / UK / RS021 — Rev:01, Nov 09 REINFORCEDSOIL RETAINING WALLS &ROCKFALL PROTECTION Product: Terramesh System, Paralink 300, Steelgrid MO, Macmat R, Rockfall Barrier CTR 05-07-B MIXED RSS FORTHE RRESHEN-KALIMASH HIGHWAY ALBANIA Problem What is thought to be one of the tallest reinforced earth structures ever to be built in Europe forms part of the newRreshen to Kalimash motorway. The 103 km long motorway is a key connection between Durres Port, Albania's primary harbour on the Adriatic Sea and Kosovo. J ourney times of between six and ten hours will be reduced to two by this new road and the new route will serve to stimulate the economy in Albania's North Eastern region. The 61km long central section of the route travels through 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 lanes through the challenging topography of the mountainous terrain at an altitude over 1,000m. This section of the works ultimately included 29 bridges (4.4km total length), 5.5km of tunnelling and 70 retaining walls totalling 6.4kmin length. Due to the mountainous topography of the area, many sections of the motorway run alternately through large steep embankment fill sections and slope cuts, with soil reinforcement, rock-fall protection, erosion control and re-vegetation measures required. The availability of large quantities of rock fills generated by the slope excavations made the choice of embankment fills a more cost effective alternative to the construction of viaducts. Of the 70 retaining walls required, those up to 15mhigh were constructed of concrete. However, the 30 walls over 15m high were designed as reinforced soil structures to re-use site won fill and reduce the visual impact. GOVERNMENT OF ALBANIA BECHTEL-ENKA J OINT VENTURE TERRAMESH, PARALINK, ROCKFALL BARRIERS ALBANIA DRAHT / MACCAFERRI Laying Parali nk pri mary reinf orcement J UNE 2008 - SEPTEMBER 2009 The first courses of the tallest wall being constructed BBA Certif ied Paral ink can accommodat e many f ill t ypes The tal lest wall nearing compl etion Solution Bechtel-Enka brought in geotechnical specialists, Officine Maccaferri (the Italian parent company of Oxford based Maccaferri Ltd) in a partnership arrangement to provide engineering design solutions for the walls. Maccaferri’s responsibility encompassed the design assistance, structural calculations and construction drawings for the 30 walls. For 20 of the walls, Maccaferri also provided supervision and construction management through its local partner Albania Draht. The 30 composite reinforced soil structures have a total facing surface area of more than 35,000 m 2 , with the maximumwall overall height of 40 m. The walls, where a steep (84°) facing was required, have been constructed using a hybrid reinforced soil system, combining two Maccaferri products; • Terramesh System, a double-twisted steel wire mesh unit which forms structures with the aesthetics of gabions but with the reassurance of soil reinforcement. • Paralink 300, a high strength polyester geogrid (primary reinforcement). The Paralink was spaced at 1 or 2m vertical centres depending upon the design requirement. These walls are amongst the highest of their type constructed anywhere in the world. Ground conditions on the site varied fromrock that was in parts competent to frequently shattered and fractured in others. In areas where the rock is at its most competent, the slopes were simply cut back to near vertical with rock ditches created to catch falling material. On the slopes up to 45 o angle above some of the walls, rockfall protection, erosion control and re-vegetation measures were installed to protect the motorway below and to promote rapid establishment of stabilising, vegetative cover. Maccaferri Macmat R1 6822 GN was used to stabilise the slope face and reinforce vegetation. On slopes where rocks could detach and fall onto the highway, SteelGrid MO 150, high tensile strength rockfall mitigation mesh was installed in conjunction with anchors and rock bolts to limit rock detachment and contain friable rock slopes. Finally, where large rocks were prone to detachment and meshing was not feasible, Maccaferri’s 500 kJ high resistance rockfall barrier (CTR 05-07-B) were installed as rockfall protection. Specialist design assistance was again provided by Maccaferri. Maccaferri Terramesh is a reinforced soil system for stabilising steep and near vertical slopes. A Terramesh unit comprises a continuous horizontal panel of woven wire steel mesh geogrid with a integral gabion fascia unit. The fascia unit is filled with hard durable rock-fill, Final design of the 40 m high wall sect ion The tal lest wall duri ng constructi on Offici ne Maccaferri S.p.A. Gl obal Headquarters ViaJ F Kennedy, 10—4069 Zola Predosa (BO) - Italy T: (+39) 051 6436000 F: (+39) 051 236507 E:
[email protected] www. Maccaf erri.com Bureau Veritas Certified Quality System Company with SINCERT and UKAS accreditation. identical to a gabion, and the geogrid tail is then sandwiched between layers of compacted backfill material, thereby reinforcing it. Having the geogrid tail integral with the fascia element removes the need for any on-site connection or pinning where errors during installation could occur due to incomplete connection, or reduced pinning frequency. Terramesh is rapid to construct, and can even reuse site won materials when suitable. Consecutive layers of Terramesh units are then constructed to form reinforced soil retaining structures of almost any height when used in conjunction with high strength Paralink geogrids. Paralink is a unique high strength uniaxial geogrid used in basal platforms over piles, soft ground or over voids caused by mine-workings, caves and so on. Available in strengths up to 1350kN in a single layer of geogrid, Paralink consists of polyester reinforcement yarns encapsulated within a tough polyethylene sheath. Having been in use since the late 1970’s, Paralink has great pedigree in the geosynthetics market. Maccaferri Terramesh and Paralink are BBA Roads and Bridges certified. The successful Bechtel-Enka/Maccaferri partnership arrangement is typical of the projects Maccaferri is increasingly undertaking with complex international projects, reinforcing their global presence, capabilities and experience. Pic.9 - View of “ area d’ int ervent o 2” Steelgri d being l ifted into position ready f or fi xing Overview of t he highest wall nearing compl etion High strengt h St eelgrid being inst all ed on rockface