ARTIFICIAL TURF

september 2002 stadia magazine

Over a period of years,Amsterdam ArenA and AFCAjax have been followingclosely the developments inthe artificial turf technologyfield. On the one hand, theyare striving for continuous

innovation and improvement of the stadium’sstate-of-the-art image and multifunctionalconcept, and, on the other hand, such turf is apossible solution to the stadium’s limitationswith regard to growing a healthy natural turf. Asa result of the “closed” and public-friendlydesign of the stadium and the intensive use ofthe pitch, the recovery capacity is limited andthe pitch needs to be replaced a number oftimes each year using a re-turfing techniquedeveloped in-house.

With the arrival of the third-generationrubber-infill artificial turf pitches, a technologicalbreakthrough has come about with regard tothe use of artificial turf for football purposes.These pitches combine sport-technicalcharacteristics that come very close to those ofnatural turf, with a consistent quality throughoutthe entire season and a practically unlimitednumber of annual playing hours. Reasonenough for many leading European profes-sional teams to already have installed theseartificial turf pitches at their training complexes.

In addition, these developments have led tothe Quality Concept for Artificial Turf from FIFA,the international football association, publishedat the beginning of 2001. Providing the pitchcomplies with a number of (sport-technical)characteristics, matches can be played on it upto World Cup qualification level. The Union ofEuropean Football Associations (UEFA) has justpresented its quality concept and has alreadyexpressed its intention to open all Europeancompetitions, including the Champions League,to artificial turf playing surfaces from thebeginning of the 2004-05 season.

Leading the wayAlthough developments in artificial turf haveaccelerated tremendously in the past fewmonths, there is still hardly any experience ofplaying matches on artificial turf at the highestlevel. This is why Amsterdam ArenA and AFCAjax have decided to take the lead and havedefined a project to optimise the sport-technicaland utilisation characteristics of rubber-infillpitches to pave the way for their application andacceptance at the highest professional level.

The aim of the project is the development of a state-of-the-art artificial turf football pitch,specifically tuned to the wishes and requirementsof AFC Ajax and within the limitations of theconditions set by UEFA, FIFA and De KoninklijkeNederlandse Voetbalbond (KNVB), the Dutchfootball association. The end result should bean artificial turf construction for football thatperforms better than the best natural turf pitchover a 12-month period. In addition, the projectalso strives for greater acceptance of artificialturf at the top level. Current systems alreadyapproach this level, but appear to be unsuitablefor application at European competition level.

User groupsTo improve current artificial turf pitches andtune them to the specific requirements thatAjax (or any other top European team) demandsfrom an artificial turf pitch (or playing surfacein general), the players, technical and medicalstaff need to play a central role. In other words,the users’ expertise, requirements and wishesmust serve as the basis for further developments.

This is why a gradual and phased introductionof artificial turf within AFC Ajax has selected soas to be able to meet the increasingly highrequirements, to allow everyone in the club tofamiliarise themselves with the new generationof artificial turf and, in this way, create a basisfor acceptance within the entire club. Users atevery level will be able to input requirementsand wishes to continually improve the concept,with the development of a pitch that is suitablefor use in competitions at the highestprofessional level being the ultimate goal.

This has already been initiated within theyouth and amateur section of the club. Oncethis section has gained sufficient experience andthe artificial turf concept has been adjusted andimproved on the basis of this experience, thestep to the professional section will be taken.

Selection of partnersSpecialist companies were chosen who wereprepared to function as partners by combiningefforts and – on the basis of the expertise andexperience of users – to test, develop andimprove their products and/or components.

The sub-areas that were designated here are:• Manufacture and installation technology;• Artificial turf fibre and backing;• Rubber-infill material;• Substructure and supporting systems, such

as irrigation and under-pitch heating.

Pitch, tune and harmoniseBen Veenbrink, Amsterdam ArenA Advisory BV, The Netherlands

Amsterdam ArenA’sfan-friendly design,coupled with intensiveuse of the pitch, is notso kind to natural turf.That is why the ArenAand AFC Ajax are fine-tuning the developmentof artificial pitches

Artificial surfaces for professional football

The end result shouldbe an artificial turfconstruction forfootball that performsbetter than the bestnatural turf pitch

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A “restricted tender” tendering procedure wasemployed, in which a pre-selection was madeof possible partners based on their reputationand financial standing. Five potential maincontractors were invited to draw up and submita technical and financial proposal, in whichthe most important selection criteria were:

• Fibre based on LSR® technology, with thepossibility of offering an alternative product;

• Proposed total concept, including supportsystems for irrigation, drainage and so on;

• Proposed approach for supporting users anduse of their input for improving the conceptduring the various phases of the project;

• Proposed approach for the maintenanceand service of the pitches;

• Total price for the delivery of the project.After thorough evaluation of the proposalssubmitted, the main contractor with the bestprice-quality performance was opted for: EdelGrass. The project team was further completedwith the following partners for the specific subareas: Ten Cate Thiolon (fibre and backing, aswell as co-ordination of all the R&D activities),Rubber Resources (rubber infill) and Arcadis(substructures and supporting systems).

Project implementationThis three-year project commenced at the endof 2001 with the objective of developing astate-of-the-art artificial turf system thatoutperforms natural grass 12 months a year.

During the three years, the current rubber-infill system based on LSR® artificial turf fibretechnology will be improved further with userinput. In addition, the intended approach aimsto conquer the emotional barrier synonymouswith artificial turf. The ultimate goal is todevelop an artificial turf football system thatperforms better than an optimum natural grasspitch. The name of the artificial turf systemunder development is ArenA Grass System®.

The project is in the following phases:• Phase 1: December 2001. Laying two

indoor pitches the size of a volleyball pitch.This phase has already been completed;

• Phase 2: May 2002. Laying a rubber-infillartificial turf training pitch at Sport Park DeToekomst for the Ajax Youth and Amateursection. This has recently been completed;

• Phase 3: spring 2003. Laying a rubber-infillartificial turf training pitch for the first andsecond teams at the training pitches nextto the Amsterdam ArenA;

• Phase 4: summer 2004. Laying a rubber-infill artificial turf main pitch (ArenA GrassSystem®) in the Amsterdam ArenA.

The realisation and introduction of each phasewill be supervised by the project partners. Apreliminary design for each phase, includingthe underlying principles and plan of approach,is drawn up and submitted to the AmsterdamArenA, who will review this partly for Ajax.

This design is initially based on:• UEFA quality concept;• FIFA quality concept;• KNVB guidelines (NOC*NSF);• Dutch national standards (environment,

health & safety).In addition, results from studies and tests fromeach phase are incorporated in the design:

[Top] The entranceof the Ajax youthtraining complexnear the ArenA

[Above] Theartificial turf pitchwith the Ajaxbuilding andAmsterdam ArenAin the background

[Left] Artificial turfinstalled at theindoor facility

ARTIFICIAL TURF

september 2002 stadia magazine

• Experience from players, technical andmedical staff. Using test circuits with theplayers under medical supervision, thesport-related characteristics of the pitch arejudged and evaluated. From a sport-relatedangle, the pitch is tested for grip, slidingfriendliness, stability, shock absorption andball behaviour. The tests will be carriedout under various weather conditions onartificial turf and natural turf to gain aninsight into the influences and differences;

• Results from the mechanical tests into thesport-related characteristics of the pitch.Users’ experiences are validated throughobjective measurement of the sport-relatedcharacteristics (for example, hardness, ballbounce). In addition, results are comparedwith a database from natural turf pitchesthroughout Europe during the season;

• Results from laboratory studies into specificcharacteristics of the system and theindividual parts, for example, the hardnessof the rubber used, resilience of the fibre;

• Investigation into improvement of utilisationcharacteristics of the pitch. The possibilitiesare investigated and instructions drawn upfor use and management, such as pitchlines, covering and under-pitch heating.

After evaluation of the preliminary design, adefinitive design is drawn up by the partnersthat will serve as a basis for laying a pitch inthat particular phase. After completion of thefirst three phases, it is expected that sufficientexpertise and experience will have been gainedto arrive at a suitable design for the final phase.

Preliminary resultsThe completion of the first two project phaseshas resulted in a system that is tuned specificallyto the AFC Ajax sport-related requirements, basedon what is currently technically possible. Thefollowing results in the various sub areas havebeen achieved as a result of this collaboration.

Manufacture and installation technique –Together with users, Ten Cate Thiolon and EdelGrass have tested turf density (number ofstitches per m2) and fibre length in order tooptimise shooting behaviour. This has resultedin the use of a slightly longer fibre and an

altered stitch density. In addition, a S&S zone(support & stability) is installed under theartificial pitch, which, together with a backingdeveloped by Ten Cate Thiolon, ensures thatthe artificial turf lies stable and remains so,while also providing extra support to the fibre.

Fibre and backing – Ten Cate Thiolon hasdeveloped and manufactured a new type ofartificial turf fibre for this project based onLSR®-fibre technology, namely Thiolon ArenaGrass®. This very sliding-friendly artificial turffibre comprises three different fibres, each in adifferent colour of green. This improves the

“natural” look of the artificial turf. The fibre alsohas a new fibrillation pattern that does awaywith the need for the turf fibre to be brushedafter installation and means an optimum playingsurface can be achieved within eight weeks.

Rubber infill – An important part of thesethird-generation artificial turf pitches is therubber-infill system. Until now, granulated cartyres were often employed as infill material.For this project, a special rubber compoundhas been developed based on playingexperience that has been translated into rubbercharacteristics such as hardness, shockabsorption, elasticity and weight. The rubberinfill complies with the strictest standards forageing, fire retardation and the environment. Itis also important that the characteristics remainconstant over a wide temperature range.

Substructure and supporting systems – From

measurements gained from tests with players,as well as mechanical tests, the ratio of sand torubber in the top layer can be adjusted so that,irrespective of the substructure construction,the same sport-related characteristics can beachieved. The substructure design focuses onwater permeability, flatness and load-bearingcapacity. Sand/Steagran has been chosen,because these components are not frostsensitive, do not break or pulverise and so willnot compact further after laying. In addition, amobile sprinkling system has been developedthat can dampen the pitch quickly and with aminimum of water to simulate dew on thepitch. The system can also be used for sprayingthe pitch with fungicide and herbicide.

Ten Cate and Arcadis are also involved inworking out the details of a pitch-coveringsystem (for extremely poor weather conditions)based on the covering system that is employedin the Ullevi Stadium in Sweden.

Project continuation In the coming months, the pitch installed at DeToekomst will be evaluated further, together withits users. The differences between the sport-related characteristics of the artificial turf pitchand the surrounding natural turf pitches, undervarious weather conditions, will be points forattention. In collaboration with the Ajaxmedical staff, an injury registration system hasbeen set up and a number of specific conditionand physiological tests will be conducted.

In addition, Ajax professional players willcarry out training sessions to provide their owninput into the design of their training pitch.Parallel to this, the partners will strive for furthertechnological improvements of components. ■

Ben Veenbrink (b.veenbrink@amsterdamarena.nl)is project manager for the new turf project on

behalf of Amsterdam ArenA and AFC Ajax

The users’ expertise,requirements andwishes must serve as the basis for further technologicaldevelopments

Average natural turf pitch during entire season

Hockey pitchused forfootball

Best natural turf as reference (May-June)

Current Rubber Infill systems

Development

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90%

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200170%

Development of artificial turf over time©

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Visit Stadia’s Sports Turf SummitAmsterdam ArenA, 6-7 March 2003

• See pages 16-17 for full details •

www.rubber-resources.com www.edelgrass.nl www.thiolon-grass.com www.arcadis.nl www.amsterdamarena.nl

Top Dutch football club Ajax intends to start playing its matches on synthetic grass.

The club already trains on synthetic grass, both indoors and outside. Synthetic grass developed and manufactured

by the partners below, who can of course hardly wait to be sent on to the famous ArenA as well.

Starting with the training pitches.

Synthetic Grass in the Amsterdam

ArenA

For more information about the partners: