This project has made progress towards the development
of a novel alternative reinforcement technique for concrete
structures with complex geometries, which are difficult to
reinforce with conventional steel. Fibre-reinforced polymers
(FRP) are woven into geometrically appropriate reinforcement
cages to provide the required strength exactly
where it is needed. Automated fabrication of the reinforcement
utilises a modification of the filament winding technique.
Being extremely lightweight, the resulting wound-
FRP (W-FRP) cages are well suited to automation of the
construction process, as they can be delivered ready for
casting in optimized concrete elements. This is a key advance
in research progress towards achieving minimum
embodied energy, optimised, concrete structures. Experimental
tests conducted on full-size W-FRP reinforced concrete
beams demonstrate the reliability of the solution proposed,
showing a new frontier for sustainable and durable
reinforced concrete structures

Ibell, TJ

Nanni, A

Orr, J

Spadea, S

English

This project has made progress towards the development of a novel alternative reinforcement technique for concrete structures with complex geometries, which are difficult to reinforce with conventional steel. Fibre-reinforced polymers (FRP) are woven into geometrically appropriate reinforcement cages to provide the required strength exactly where it is needed. Automated fabrication of the reinforcement utilises a modification of the filament winding technique. Being extremely lightweight, the resulting wound- FRP (W-FRP) cages are well suited to automation of the construction process, as they can be delivered ready for casting in optimized concrete elements. This is a key advance in research progress towards achieving minimum embodied energy, optimised, concrete structures. Experimental tests conducted on full-size W-FRP reinforced concrete beams demonstrate the reliability of the solution proposed, showing a new frontier for sustainable and durable reinforced concrete structures

Orr, John

Ibell, Timothy

Spadea, S

Nanni, A

University of Miami: Scholarship Miami

Filament winding fabrication of FRP reinforcement cages

Apollo (Cambridge)

OCTOBER2017 5Concrete Plant InternationalWorldwide English EditionICCX SPECIAL ICCX Middle East Debuts in Sharjah with 100 Exhibitors NEWS Building withrobots and 3D printers CONCRETE PRODUCTS Jasto renews plant equipment for concreteblock production CONCRETE PIPES AND MAN HOLES AmeriTex taps new Texas markets withadvanced new plant PRECAST CONCRETE ELEMENTS New non-load bearing partition wallpanel production in Vietnamwww.wiggert.comWorldwide Supplier ofCustomized  Concrete Plant  Solutionswww.cpi-worldwide.comMIDDLE EAST 201726. – 27.11.2017 I Sharjah, United Arab EmiratesVisit us at booth #861705_cpi_U1-4_en_Layout 1  05.09.17  09:32  Seite 1CONCRETE TECHNOLOGYCPI – Concrete Plant International – 5 | 2017 www.cpi-worldwide.com62This project has made progress towards the developmentof a novel alternative reinforcement technique for concretestructures with complex geometries, which are difficult toreinforce with conventional steel. Fibre-reinforced poly-mers (FRP) are woven into geometrically appropriate rein-forcement cages to provide the required strength exactlywhere it is needed. Automated fabrication of the reinforce-ment utilises a modification of the filament winding tech-nique. Being extremely lightweight, the resulting wound-FRP (W-FRP) cages are well suited to automation of theconstruction process, as they can be delivered ready forcasting in optimized concrete elements. This is a key ad-vance in research progress towards achieving minimumembodied energy, optimised, concrete structures. Experi-mental tests conducted on full-size W-FRP reinforced con-crete beams demonstrate the reliability of the solution pro-posed, showing a new frontier for sustainable and durablereinforced concrete structures.Flexible formworks use a system of flexible sheets of highstrength, lightweight fabric to allow complex concrete shapesto be easily cast, thus facilitating the construction of optimisedstructures [1]. However, the need to assemble quite complexreinforcing cages together with the low durability of steel re-inforcement in thin walled structures, are two reasons whylarge-scale deployment of this technology has not yet oc-curred. The use of FRP as internal reinforcement can help toovercome these kinds of issue since it can be accuratelyshaped during manufacture according to the final design de-mands.Serviceability limit states, rather than ultimate limit states, nor-mally govern the design of FRP reinforced structures, with thecontrol of deflection being very often the most decisive checkin the design process [2, 3]. Additionally, the lack of yieldingof FRP reinforcement requires the design of over-reinforcedsections to obtain concrete crushing flexural failure and pre-vent sudden FRP rupture. This issue is even more problematicwhen designing optimized structural shapes, which lead – bydefinition – to slender and deformable structures. Another relevant design problem is modelling the mecha-nisms of shear resistance in FRP reinforced concrete mem-bers. Shear failure of reinforced concrete structures is brittleFilament winding fabrication of FRP reinforcement cages Knitting Bespoke Reinforcement for New Concrete Structures ! Saverio Spadea, University of Dundee, School of Science and Engineering, Dundee, UKJohn Orr and Tim Ibell, University of Cambridge, Department of Engineering, Cambridge, UKAntonio Nanni, University of Miami, Department of Architectural, Environmental and Civil Engineering, Coral Gables, USAFig. 1: Design Method03a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 62CONCRETE TECHNOLOGYwww.cpi-worldwide.com CPI – Concrete Plant International – 5 | 2017 63and can be tremendously sudden and dangerous when deal-ing with FRP shear reinforcement [4-6]. Furthermore, the mostup-to-date design codes do not provide specific guidance toanalyse the shear strength of non-prismatic concrete mem-bers [7].DesignTo develop a model that can efficiently predict the structuralbehaviour of complex structural elements and consequentlyperform the structural optimization of flexibly–formed con-crete beams reinforced with FRP, a method of analysis withbroad applicability was developed. The geometry of the fab-ric formed member and the distribution of the reinforcementwas modelled in a closed form allowing for variation in thesection dimensions along the member length. The optimiza-tion parameters aim to obtain the minimal mass of concreteand observing the capacity design requirements as per themostly recognized design codes [8, 9].The computational procedure followed, suitable for staticallydeterminate structures is briefly outlined in Fig. 1. Additionaldetails of the design method can be found in [10].The code produces a ‘.stl’ output file of the designed beam,which details all the information pertaining to the geometryof the structural elements and is utilised in the automation ofreinforcement construction.! Dr Saverio Spadea is University Lecturer in Structural Engi-neering Design at the University of Dundee (UK) and seniormember of the Italian Association of Professional Engineers. Previously, he held research positions at the University of Bath(UK) and University of Salerno (Italy), and was a Fulbrighter at theUniversity of Miami (US). With his research, he aims to explorenovel structural forms, different materials, and new building techniques for sustainable construction. s.spadea@dundee.ac.uk! Dr John Orr is University Lecturer in Concrete Structures at the University of Cambridge. Dr Orr is a Chartered Structural Engineer. He was previously Director of Research and AssistantProfessor in Civil Engineering at the University of Bath, fromwhere he obtained his Masters and PhD degrees in Engineering.His teaching and research are related to sustainable construction,with emphasis placed on concrete and structural optimisation. jjo33@cam.ac.uk ! Tim Ibell is the Sir Kirby Laing Professor of Civil Engineering atthe University of Cambridge. He is a Fulbrighter, a Fellow of theRoyal Academy of Engineering and a Past President of the Institu-tion of Structural Engineers. His research is aimed at the innova-tive design of concrete structures. tjo10@cam.ac.uk! Antonio Nanni is Professor at the University of Miami andChair of the Department of Civil, Architectural, and Environmen-tal Engineering. He is a Structural Engineer and Fellow of theAmerican Concrete Institute (ACI), the American Society of CivilEngineering (ASCE). He currently serves as Chair of ACI Commit-tee 549 and Subcommittee 562-E and voting member of ACICommittees 437, 440, and 562. His research interests are in the field of civil infrastructure sustainability and renewal. nanni@miami.eduthere is a solutionWhencorrosion stains ruin your concrete  www.ecoratio.comAsk our product specialist Tony Coopetony@ecoratio.com+44 7712 816 821 (UK)03a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 63CONCRETE TECHNOLOGYCPI – Concrete Plant International – 5 | 2017 www.cpi-worldwide.com64Manufacturing Computer controlled winding of impregnated carbon fibresaround a set of FRP bars provides the opportunity to obtaindurable, lightweight, and ready-to-use reinforcement cages. The manufacturing of web reinforcement is operated bymeans of a process based on the filament winding fabricationtechnique, which consists on wrapping continuous fibresunder tension over a rotating mandrel. As the mandrel ro-tates, a carriage moves horizontally to lay down CFRP fibresin the designed pattern. After the required number of layersare wound, the reinforcement cage is cured and subsequentlyremoved from the mandrel. This method of manufacturingprovides a satisfactory control over fibre placement and uni-formity of the material structure and it is generally used toproduce continuous hollow shapes with constantly uniformcross section. In the present application, curved CFRP bars responsible forproviding the flexural strength to the concrete beams are at-tached to the mandrel according to the designed reinforce-ment geometry. The manufacturing system has sufficient con-trol to allow the winding of any number of carbon tow layersin the form of spirals with variable cross section (Fig.2). After both the winding and curing processes occur, the rein-forcing bars are maintained in the curved configuration by thecured wound reinforcement (Fig. 3). Details of the raw mate-rials used can be found in [11].Flexibly Formed Beams With the aim of validating both the optimization procedureand the W-FRP reinforcement cage manufacturing method,eight FRP reinforced fabric formed beams were designed andtested. The adopted static scheme is a simply supportedbeam with a three- meter span and a half-meter overhang oneach end, subject to a uniformly distributed load (see Fig. 4).The design dead load was 2.5 kN/m and design live load was7.5 kN/m. The design concrete strength was C30/37. Longi-tudinal reinforcement was provided by GFRP bars in the topand CFRP bars in the bottom of the section.Two different study cases were taken in consideration:- The first set of beams (Set J – beams J.0, J.2, J.3-3, J.6) isintended to simulate a precast fabric formed joist sup-porting a lightweight floor (e.g. all-FRP or timber floor).- The second set of beams (Set T – beams T.0, T.2, T.2-2,T.4) aims to reproduce the use of a precast fabric formedbeam with an in-situ casting of a concrete floor. In the ex-periments performed, the beam and the slab elementswere cast together for ease of construction. A 3D visualization of the beam’s topology, as generated bythe design code, is also shown in Figures 5a and 5b. Each setis composed of four beams having identical concrete geom-etry and longitudinal reinforcement but different W-FRP shearreinforcement. Whereas they all satisfy the first three pointsof the above-mentioned computational procedure, onlybeams J.6, J.3-3, T.4, and T.2-2 have the required shearstrength to fail in flexure. The wound reinforcement in beams J.3-3 and T.2-2 is quanti-tatively similar to the one employed in beams J.6 and T.4, re-spectively. However, it is arranged in two shifted patterns, aim-ing at increasing the wound reinforcement diffusion and ide-ally increase the overall efficiency of the cage.Fig. 2: Filament winding machineFig. 3: FRP optimized reinforcement cageFig. 4: Experimental setup03a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 64CONCRETE TECHNOLOGYFigure 6 illustrates the T.2-2 beam reinforcement. The first pat-tern (highlighted in red) is composed by 2 layers arranged inthe same geometrical configuration employed in beam T-2 (2layers) and beam T-4 (4 layers). The second pattern (high-lighted in blue) is composed by 2 additional layers, havingthe effect of halving the shear reinforcing spacing toughmaintaining the shear reinforcement ratio employed in beamT-4. Similar criteria were used to design the reinforcementemployed in beam J.3-3.Table 1: Details of the beamsdescription Set J Set Tbeam length (mm) 4100 4100clear span (mm) 3000 3000flange width (mm) 300 900flange thickness (mm) 60 60web minimum width (mm) 85 85beam depth at midspan (mm) 265 190beam depth at supports (mm) 180 150beam depth at ends (mm) 95 110top reinforcement at supports (mm) 2 × #3 GFRP 3 × #3 GFRPbottom reinforcement at midspan (mm) 3 × #3 CFRP 4 × #3 CFRPconcrete volume (m3) 0.14 0.27wound CFRP layers (#) 0 / 2 / 6 / 3+3 0 / 2 / 4 / 2+2Specimen ID J.0 / J.2 / J.6 / J.3-3 T.0 / T.2 / T.4 / T.2-203a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 65CONCRETE TECHNOLOGYCPI – Concrete Plant International – 5 | 2017 www.cpi-worldwide.com66The essence of flexible construction is to secure the fabric ona supporting frame in order to achieve the desired form oncethe formwork is filled with concrete. In the present work, thefabric is draped into a plywood supporting frame to shapethe non-planar lateral surface of the web. Control of the beamelevation is achieved using a simple timber member (a “keel”),pre-cut to the desired elevation. Fig. 7 shows the intrados ofa flexibly formed concrete beam. Further details of the method of construction and results ofthe experimental tests can be found in [12].Test ResultsA synthesis of the experimental results obtained on each ofthe tested beams and the relative analytic predictions are re-ported in Table 2. Results obtained are sufficiently in agree-ment with the predictions. Only beam T.0 exhibited an exper-imental capacity significantly higher than predicted. Final RemarksA new method of manufacturing CFRP shear reinforcementfor optimised concrete beams by winding carbon fibresaround a bundle of FRP reinforcing bars was developed. Themethod is well suited to automation and mass production ofentire reinforcing cages. Fabric formworks and flexibility ofthe winding process greatly reduces technical limitation onthe shapes that can be built. The effectiveness of the reinforcing material is established bymean of flexural tests conducted on real scale optimizedbeams subject to a uniformly distributed load. The results ofthose tests support the following conclusions:- The W-FRP, if used in requested quantity and in the ap-propriate geometry, is able to prevent shear failure ofsuch members; - The existing FRP provisions can be conveniently used topredict the behaviour of FRP optimized beams, througha section-by-section analysis.Fig. 5: 3D visualization of the beams: a) Set J; b) Set TFig. 7: Flexibly formed concrete beam.Fig. 6: 3D visualization of beam T.2-2: two shifted patterns are distinguished by red and blue coloursTable 2: Materials strength, predicted failure and experimental failurespecimen Predicted UDLs at Failure Experimental Failure Predicted to Experimental Flexure Shear mode UDL UDL ratiokN/m kN/m kN/mJ.0 73.2 25.1 Shear1 33.3 1.33J.2 83.4 57.4 Shear2 59.0 1.03J.6 72.3 76.7 Flexure3 87.7 1.21J.3-3 72.3 84.9 Flexure3 73.1 1.01T.0 60.2 18.1 Shear1 41.3 2.28T.2 68.7 55.6 Shear2 63.9 1.15T.4 59.4 70.6 Flexure3 60.0 1.01T.2-2 59.4 75.0 Flexure3 70.1 1.181Shear Tension Failure; 2Shear Tension Failure and W-FRP rupture; 3Flexural failure due to concrete crushing; 4See Figure 3.03a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 66CONCRETE TECHNOLOGYwww.cpi-worldwide.com CPI – Concrete Plant International – 5 | 2017Future work will build on the success of this project to en-hance the optimisation and analysis procedures and intro-duce pre- and post-tensioning and bespoke participatingformwork.AcknowledgmentsThis work was funded by the Engineering and Physical Sci-ences Research Council under grant EP/M01696X/1. The firstauthor acknowledges the J. William Fulbright Foreign Schol-arship Board for the opportunity of developing part of this re-search at the University of Miami. !References[1] Orr, J.J., A. Darby, T. Ibell, and M. Evernden, Design methods forflexibly formed concrete beams. ICE Structures and Buildings, 2014.167(SB1): p. 1-13.[2] Nanni, A., A. De Luca, and H.J. Zadeh, Reinforced Concrete with FRP Bars: Mechanics and Design. 2014, Boca Raton, FL: CRC Press.[3] Ascione, L., G. Mancusi, and S. Spadea, Flexural behaviour of con-crete beams reinforced with GFRP bars. Strain, 2010. 46(5): p. 460-469.[4] Matta, F., A.K. El-Sayed, A. Nanni, and B. Benmokrane, Size effect onconcrete shear strength in beams reinforced with fiber-reinforcedpolymer bars. ACI Structural Journal, 2013. 110(4): p. 617-628.[5] Ascione, L., A.G. Razaqpur, and S. Spadea, Effectiveness of FRP stirrups in concrete beams subject to shear, in 7th International Conference on FRP Composites in Civil Engineering (CICE 2014).2014: Vancouver (Canada).[6] Razaqpur, A.G. and S. Spadea, Shear Strength of FRP ReinforcedConcrete Members with Stirrups. Journal of Composites for Con-struction, 2015. 19(1).[7] Orr, J.J., T.J. Ibell, A.P. Darby, and M. Evernden, Shear behaviour of non-prismatic steel reinforced concrete beams. EngineeringStructures, 2014. 71: p. 48-59.[8] CSA S806, Design and Construction of Buildings Components withFiber-Reinforced Polymers. 2012, Canadian Standard Association:Toronto, Ontario, Canada.[9] ACI 440.1R, Guide for the Design and Construction of StructuralConcrete Reinforced with Fiber-Reinforced Polymer (FRP) Bars.2015, American Concrete Institute: Farmington Hills, MI.[10] Spadea, S., J. Orr, T.J. Ibell, and A. Nanni, Development of New FRP Reinforcement for Optimized Concrete Structures, in High TechConcrete: Where Technology and Engineering Meet: Proceedingsof the 2017 fib Symposium, held in Maastricht, The Netherlands,June 12–14, 2017, D.A. Hordijk and M. Luković, Editors. 2018,Springer International Publishing: Cham. p. 867-876.[11] Spadea, S., J. Orr, Y. Yang, and A. Nanni, Wound FRP shear reinforcement for concrete structures. Journal of Composites for Construction, 2017. 10.1061/(ASCE)CC.1943-5614.0000807 [12] Spadea, S., J.J. Orr, and A. Nanni, New frontiers for the use of FRPreinforcement in geometrically complex concrete structures, in 8thInternational Conference on FRP Composites in Civil Engineering(CICE 2016). 2016: Hong Kong.MIDDLE EAST 201726. – 27.11.2017 I Sharjah, United Arab EmiratesVisit us at booth #4603a-Technology_050-067_en_Layout 1  06.09.17  11:05  Seite 67

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Filament winding fabrication of FRP reinforcement cages

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