Prestressed concrete factory building of'Algemene Kunstzijde Unie N.V.' in the Netherlandsby F. J. C. BarendsWhen after the war it became more and more desirable, not onlyto build quickly but also to obtain a freeer hand in fitting up themachines by means of placing the columns further from each other,pre-stressed concrete made its appearance in the Netherlandsfactory builders' world.The building-method for low factory buildings, when preparingthe foundations, of making ready, the prefab-beams and roofingslabs and of fixing these at their proper place later on, generallymeans a saving of building time. By applying the pre-stressing intothe prefab-beams, a span 1.5 to 2.5 times larger can be obtained incomparison with normally reinforced concrete with a similarconstruction height. This means not only that the distancesbetween the centre lines of the columns can be taken greater butalso a saving of building time and cost of foundation work. Anadditional advantage can be drawn from the keeping underpressure of the entire section of the concrete, giving a betterprotection of the steel from outside chemical influences than incase of normal reinforced concrete in the tension zone.In comparison with monolithic, reinforced concrete building,with the concrete cast in situ, it should further be noted thatallowing a higher concrete tension in the prefab pre-stressedconcrete beams made on the ground on the site or in a specialfactory is certainly permissible because the adapting of the ironwork and the casting of the concrete had better be done on theground than high up in the air.It is necessary that proper attention should be given to the form-work moulds, which must be provided with plywood or steelplates, which, especially in case of much repeated use not onlymeans an eventual saving of maintenance costs of the moulds, butalso gives smooth, stark concrete beams with a much densersurface.The application of two pre-stressed concrete beams in one of thefactory buildings at Arnhem in 1949, a pre-stressed concrete era,as it were, was opened. The total number of pre-stressed beamshaving been applied for the A.K.U. factory buildings amount toabout 1,800 now, varying from 5 to 30 metres in length.These first two beams, 16 metres in length and 8.30 m' centreshave an I cross-section of 125x38 cm and a reinforcement of12 Freyssinet-cables of 12 wires 5 mm each. When making andstressing the cables we experienced several teething troublesas the deforming of the gains, which were still made of cardboardat the time, the slipping of the wires, both through the stay plugsand through the stay wedges of the jacks. The calculated maximalultimate concrete tension is 130 kg/cm- and for the steel 94 kg/cm2,55 kg of high-grade steel (Samesco) being used per nr' of concrete.From a large number of projects, in steel construction as well as inreinforced concrete and pre-stressed concrete, the concreteconstruction with pre-stressed concrete beams was selected forthe yarn finishing house of the Enkalon plant at Emmen, being themost economic way of construction, in connection with therequirements of the operations.Owing to two extensions had to be made meanwhile, the totalnumber of pre-stressed beams has grown to 465.These beams of a 20 metre span have an I cross section of 46 ? 126cm and lie 2.00 and 3.00 metres centres. Besides a roof constructionof reinforced concrete casket-slabs, there is moreover a loweredceiling construction. Between the ceiling and the roof the con-ditioning and pipe channels and lighting have been placed. Eachbeam is reinforced with 7 Freyssinet cables of 12 wires ? 5 mmeach and contains 40.2 kg of high-grade steel per m' of concrete(photo I).In the same period 103 beams of 10 metres and 16 beams of 15metres in length were applied for a fibre-finishing house, lactambuilding and a yarn finishing house. These beams, made by a specialprestressed concrete firm on the Hoyer system, were providedat the ends with projecting bars of concrete steel. After settingthe prefab-beam, in the formwork on the required height thesupporting main girders were cast (see photos 2 and 3).In the A.K.U. plant at Ede in 1951 14 pre-stressed concrete beamsof a span of 30 metres were used for the construction of a cellulosewarehouse. These beams of an I cross section of 36 ? 160 cm lie5.33 metres centres and each contain 9 Freyssinet cables of 12wires ? 5 mm. The quantity of high-grade steel per m3of concreteamounts to 49 kg. The beams rest on single concrete frames andwere made between these frames and lifted up to be mounted(photo 4).For the extension of a spinning room in Arnhem was chosen theapplication of 53 pre-stressed concrete beams, on the Hoyer-system, each 20 metres in length. These beams, which are factorymade, were transported to the building place by special lorriesand carried to their appropriate place via the travelling cranerunning over the main frames, which had been cast beforehand,and then fixed.The 18 pre-stressed beams for a vacuum drying plant in the H.K.I.factory at Breda have an I cross section of 40?125 cm and lie225 cm centres.The span is 26.00 m1. These beams, made with 6 cables accordingphoto I.assemblingprestressed beamsof yarn buildingat Emmen196 Cement 7 (1955) Nr 7-8photo 3. detail of bearing of a prestressed concrete beam intothe main girdersto the rreyssinet system and containing a quantity ot high-gradesteel of 48 kg per m3of concrete, were constructed beside thebuilding on the ground (photo 5 building year 1953).In 1953 a penthouse was wanted for the dry unloading of salt fromrailway vans, which penthouse was made of concrete in connectionwith the maintenance. This penthouse, overhanging 6.50 metres,consists of a number of prefab concrete beams, reinforced withspecial steel, the projecting steel at the heads of which is fixed in aheavy beam. This concrete beam has a span of 12 metres and onboth sides of it there is an overhang of 3 metres, its furthermeasurements being: width 100 cm and height 80 cm.The reinforcement consists of 14 cables (Freyssinet) each of 12wires 0 7 mm. Besides the appearing bending moments, thesecables also take up the torsional stresses caused by the turningmoment (photo 6). The foundation of the penthouse-constructionphoto 5. assembling of the prestressed girders for the buildingof the vacuum drying of the rayon-yarn works of theH.K.I, at Bredaphoto 2. fibre-building of A.K.U.'s Enkalon Works at Emmenin course of constructionphoto 4. view of theactivities duringthe building of the cellu-lose stores in the rayon-garn building of the A.K.U.at Ede Photo Renes, Arnhephoto 8. prestressed joints for the central stores of the A.K.U.near Arnhem photo 6. penthouse of prestressed concrete for underloadingof salt of a salt-bunker on the terrain of the rayonfibre works of A.K.U. in the 'Kleefse Waard' nearArnhemphoto 7. detail of the ending of the prestressed beam of thepenthouse of the salt bunker of the A.K.U. near Arnhemphoto 9. prestressed sleepersis completely separated from the main building, in this way,however, that the iron, which project from the roof plane on thespot of the two pillars, and which take up horizontal forces, isfixed in the bunker building behind.On photo 7 the ends of the beams with the disguised stay plugscan be seen.For covering lantern light openings 8 metres wide of warehousesin Arnhem, pre-stressed joists 5.20 m in length were used. Thesejoints have across section of 12 14cm, lie0,82 m1centres and arereinforced with wires 0 2.5 mm on the Hoyer system. Some ofthese 950 joints can be seen on photo 8.Finally, we will mention the use of a large number of pre-stressedconcrete sleepers of the slow transport type in the railway systemon our Arnhem factory site (see photo 9).SAMENVATTINGVoorgespannen beton ? de fabriek van deAlgem. Kunstzijde Unie N.V. in Nederlanddoor F. J. b. BarendsHet voorgespannen beton deed na de oorlog zijnintrede in de fabrieksbouw, omdat, naast snellerbouwen, grotere kolomafstanden meer vrijheidgaven t.o.v. het plaatsen van machines. Elders ophet fabrieksterrein kunnen tijdens het maken vande funderingen prefabbalkcn en dakplaten wordenvervaardigd. Door voorspannen van deze balkenkan t.o.v. gewapend beton IJ tot 2Jzo grote over-spanning worden bereikc; dus ook besparing aanbouwtijd en -kosten. Chemische invloeden zullenminder bezwaar opleveren door het steeds onderdruk blijven van de gehele betondoorsnede.Hogere spanningen in prelab-betonbalken is zekertoelaatbaar, daar storten op de grond (balkenveldof speciale fabriek) beter kan geschieden dan in delucht. Bekistingsmallen met triplex of staalbepla-ting geven vooral bij grote herhaling, besparingaan onderhoudskosten van de mallen en bovendiengladde strakke betonbalken met veel dichter huid-oppervlak.In 1949 werden 2 voorgespannen betonbalken ineen fabrieksgebouw te Arnhem toegepast. Hedenzijn er 1800 balken, vari?rend van 5 tot 30 m bij deA.K.U. aangebracht.Moeilijkheden in het begin worden besproken.Het garengebouw van de Enkalonfabriek inEmmen bleek het meest economisch met voor-gespannen betonbalken. Freyssinet-kabels enSamesco-staal zijn hier toegepast.Balken, systeem Hoyer, hadden aan de koppenuitstekende staven rondstaal.In Ede bij de A.K.U. en te Breda bij de H.K.I. zijnvoor een cellulose-magazijn voorgespannen beton-balken toegepast.Interessant is de luifel voor het droog lossen vanzout. Voorgespannen roedebalken zijn toegepastbij brede lichtkap-openingen te Arnhem.Het eigen spoorwegnet voor langzaam vervoerheeft voorgespannen dwarsliggers.SOMMAIRELe b?ton pr?contraint dans l'usine AlgemeneKunstzijde Unie (A.K.U.) N.V., Pays-Baspar M. F. 1. B. BarendsD?s apr?s la guerre le b?ton pr?contraint a com-menc? d'?tre appliqu? dans les constructionsd'usines: le d?lai de construction s'en trouvaitr?duit, les distances aggrandics entre axes descolonnes offraient plus de latitude pour la mise enplace des machines; en m?me temps que le coulagedes fondations, des poutres et des ?l?ments detoiture peuvent ?tre pr?fabriqu?s; la pr?con-trainte augmente les port?es des poutres ? raisonde IJ ? 2i par rapport aux poutres en b?ton arm?.Les effets d'agression~chimiques sont moins ?craindre, ?tant donn? l'absence de la fissuration.Il est raisonnable d'augmenter les taux do con-trainte admissibles pour le b?ton des poutres pr?-fabriqu?es. car le b?tonnage y est beaucoup plussoign?, que dans le cas du coulage en place. Desmoules avec rev?tement int?rieur de contreplaqu?ou de t?les, donnent des surfaces de b?ton lisses etserr?es et r?duisent l'entretien des moul.-s, ? par-tir d'un nombr- suffisant d'?l?ments ? couler.En 1949, 2 poutres en b?ton, destin?es ? une usine? Arnhem, furent pr?contraintes. A ce jour, 1800poutres pr?contraintes pourvus de port?es variantde 5 ? 30 m. sont en service dans les usines del'A.K.U. Les difficult?s du d?but sont discut?esdans l'article.Pour la construction d'une filerie ? Emmen (usinesEnkalon) une solution comportant des poutrespr?contraintes ?tait la plus ?conomique. Des cablesFrcyssinet et de l'acier dur 'Samesco'ont ?t? appli-qu?s. Des poutrelles, syst?me Hoyer, ?taientmunies d'acier en attente ? leurs extr?mit?s.Pour des d?pots de cellulose ? Breda et ? Ede despoutres pr?contraintes ont ?t? utilis?es.Le r?seau de chemin de fer int?rieur des usines del'A.K.U. utilise des traverses en b?ton pr?con-traint.ZUSAMMENFASSUNGVorgespannter Beton in der Fabrik der All-gemeinen Kunstseide Union G.m.b.H. inHolland von F. ). B.BorendsNach dem Kriege begann der Spannbeton im Fa-briksbau eine Rolle zu spielen, da -nebst desrascheren Baufortschrictcs- die damit erzieltengr?sseren St?tzenabst?nde mehr Freiheit im Hin-blick auf die Aufstellung von Maschinen gestatten.W?hrend der Herstellung der Fundamente k?nnenanderswo auf dem Fabriksterrain Tr?ger undDachplatten praefabriziert werden. Durch Vor-spannung kann im Vergleich zu Stahlbeton dieSpannweite li bis 2} mal so gross gemacht undauch an Zeit und Kosten gespart werden.Chemische Einfl?sse werden weniger Schwierig-keiten verursachen, da im Betonquerschnitt nir-gends Zug auftritt. Zweifellos sind in preafabri-zierten Konstruktionen h?here Spannungen zu-l?ssig, da das Betonieren unten auf dem Boden(auf dem Tr?gerfeld oder in einer speziellen Fa-brik) sorgf?ltiger geschehen kann als in der Luft.Verschalungselemcnto mit Triplex oder Stahl-bekleidung bringen besonders bei h?ufiger Wie-derholung im Gebrauch Ersparnisse an Unterhal-tungskosten mit sich und bewirken ?berdies?usserst glatte und dichte ?etonoberflachen.Im Jahre 1949 wurden in einem Fabriksgeb?ude inArnheim 2 vorgespannte Tr?ger verwendet; heutesind es bei der A.K.U. nicht weniger als 1800Balken in L?ngen von 5 m bis 30 m.Es werden die Schwierigkeiten besprochen, die imBeginn ?berwunden werden mussten.Beim Garngeb?ude der Enkalonfabrik in Emmenerwiesen sich Tr?ger aus Spannbeton als die ?ko-nomisch vorteilhafteste L?sung. Es wurden Freys-sincikabel und Samesco-Stahl verwendet.Praefabrizierte Balken nach dem System Hoyerwaren mit ?ber die Enden herausragenden St?benversehen.Bei der A.K.U. in Ede und der H.K.I. in Breda sindf?r ein Celulosemagazin Balken aus Spannbetonverwendet.Interessant ist ein Vordach, um Salz beim Ausladentrocken zu halten.Glasssprossen f?r eine breite Oberlichte in Arn-heim sind aus Spannbeton verfertigt.Im Eisenbahnnetz f?r langsamen Verkehr liegenSchwellen aus Spannbeton.198 Cement 7 (1955) Nr 7-8