Structural performance of prefabricated cage reinforced concrete composite structures

Beema Subair1, Sumayyath M.M2

1Student, Dept. of Civil Engineering, ICET Mulavoor, Kerala, India

2Asst.Professor, Dept. of Civil Engineering, ICET Mulavoor, Kerala, India

Abstract -In this study, reinforced concrete has been replaced with a prefabricated reinforcing cage system for beam, in terms of their ultimate capacities, flexural performances, , ductilitybehaviour, andloadv/sdisplacement curves Prefabricated reinforced beams with varied cage thicknesses are compared to conventional RCC beams. Using varied stirrup opening shapes, the shear confinement and spiral confinement effects from the chosen thickness were evaluated and compared to the conventional RCC model. The models are done by using ANSYS 2022 Software, and results are compared to conventional RCC beam. The results show that a 6mm cage thickness is better for beams. For beams, the performance of models like the diamondandellipticalmodels is improved by 35.3% and 2.7%, respectively. With a 13.22% load increase The results of this study indicate that prefabricatedcages for beamwith various cuttingshapes can improve performance.

Key Words: prefabricated cage system (pcs), cage thickness 3mm(T3), cage thickness 4mm(T4), cage thickness 5mm(T5), cage thickness 6mm(T6),Reinforcedcementconcrete(RCC)

1. INTRODUCTION

One of the most popular composite systems worldwide is reinforced concrete. The effectiveness of individual reinforced concrete system components has an impact on theeffectivenessofthesystemasawhole.Toenhancethe performanceofstructuralelements,researchhasbeendone onavarietyoftechnologiesthatcouldreplacethetraditional reinforcedconcretesystem.ThePrefabricatedCageSystem (PCS)isoneofthesestudies.hisapproachisbasedonthe ideaofusingperforatedsteelpipesorplatesinplaceofthe traditional concrete reinforcing. Work on PCS-reinforced columns using standard and high strength concrete the studies revealed that the columns reinforced with PCS exhibitedelasticbehavioursimilartothatofconventionally reinforcedconcretesystems,buttheyalsodisplayedmore ductilebehaviour,hadahigherenergyabsorptioncapacity, andincreasedthestrengthanddisplacementcapacityofthe column. Furthermore, it was discovered that the PCS's confinementeffectkeptthesteelfrombuckling.

AlthoughtheproductionofPCSreinforcementcanbemore expensivethanconventionalreinforcementforaparticular structural member, PCS can be thought of as more

inexpensivefromanengineeringstandpointthantraditional reinforcingsystems.Comparedtotraditionalreinforcement systems,PCScanbethoughtofasbeingmorecost-effective. ThefabricationofPCSreinforcementusesfarlessmaterial than traditional reinforcing systems and takes much less time. Additionally, fabricating PCS might considerably cut labour costs. Reducing labour costs, which account for a significant portion of construction costs, lowers overall constructioncosts.theuseofPCSreinforcementincolumns providesaconsiderablesavingfromconstructioncostsand time.

Work on reinforced concrete beams with continuous rectangular spiral reinforcement in this, the Experimental research is done on the behaviour of shear-critical reinforcedconcretebeamswithrectangularcrosssections and continuous rectangular spiral reinforcement as transverse reinforcement. Additionally, a sophisticated rectangularspiralreinforcementwithverticallinksthatare orientedinfavourofshearispresentedandputtothetest. Thereareeightbeamsintheexperimentalprogramme.The results of the tests clearly show that the adoption of rectangular spiral reinforcement improved the shear performanceandbearingcapacityofthetestedbeam.

Inthisstudy,prefabricatedreinforcedbeamswithvarious thicknessesarecomparedtoconventionalRCCbeamsand columns in terms of their ultimate capacities, flexural performances,spiralconfinementeffect,ductilitybehaviour, load v/s displacement curves, and opening shapes of the stirrupswithvariousbreadth.Themodelsaredonebyusing ANSYS 2022 Software, and results are compared to conventional RCC beam, the diamond shape performs significantlybetterthantheconventionalRCC.

1.1 PCS system and confinement effect

One of the most common composite systems utilized globallyisreinforcedconcretesystems.Theeffectivenessof thereinforcedconcretesystemasawholeisinfluencedby the effectivenessof itsindividual components. Toenhance theperformanceofstructural elements,researchhasbeen done on a variety of technologies that could replace the traditional reinforced concrete system.in this the load capacities of reinforced beam and column, to enhance the structural performance of beam and column prior to the conventionalsystem Forthisthethicknessisvariedfrom3

to 6 among the better thickness one the opening shape is variedtoelliptical,triangle,diamond.

It is well acknowledged that using continuous spiral reinforcement in reinforced concrete (RC) elements with cycliccross-sectionscansignificantlyincreasetheconcrete's strength and ductility, and consequently the structural element'soverallseismicreactionandcapacity.thisresearch examinesthestructuralperformanceofbeamsusingsingle spiral confinements and double spiral confinements. The confinement effect is often related to the structural parts' abilitytosustainloads.

1.2 Objectives and scopes

The main objective of the study is the flexural bending performanceoftheprefabricatedcagestructureinbeamand finding the optimum thickness, weight and strength performance in comparison with conventional reinforcementasperIScode Fromtheoptimumthickness performing the other parametric study like, effect of the confinementshape(elliptical,triangle, diamond),Effect of the spiral confinement (double, single), and the output resultslikeultimatedeflection,ultimateload,percentageof improvementinstrengthareevaluateandcompared

In the present study new reinforcement system called prefabricatedcagestructureisintroduceinbeam.Thestudy willgiveanideaabouttheperformanceoftheprefabricated cagestructureinbeaminplaceofconventionallyreinforced concrete,ThemodelsaredonebyNonlinearstaticanalysisin WorkbenchofAnsys(2022).

2. FLEXURAL BENDING PERFORMANCE OF THE PCS IN BEAM

Analysisonprefabricatedcagestructureinbeamandfinding the flexural performance. For this selecting the optimum thicknessofthecagefromT3,T4,T5,T6bycomparingthe resultwiththeconventionalRCCbeam.Forallmodels,the prefabricatedbeam'sdimensionsare100x180x1000mmand insteeltubethecagethicknessisvariedfrom3to6mmthe steeltubedimensionsare80x160x3mm(T3),80x160x4mm (T4),80x160x5mm (T5), 80x160x6mm (T6). Material properties of the beamsare Young’s modulus 2 ×105 Mpa, Poisson’s ratio 0.15, Grade M25, Density 2400 kg/m3 and materialpropertiesofsteeltubeisYoung’smodulus2×105 Mpa,Poisson’sratio0.3,Density7850kg/m3

2.1 Modelling

ConventionalRCCbeamandPrefabricatedcagesforbeam with varying thickness are modelled in ANSYS software. ConventionalRCCisdesignedasperIScodehavingmainbar 12mmdiameterand8mmdiameterstirrupsareusedwitha spacingof100mmc/c.Prefabricatedthicknessvariedlike T3, T4, T5, T6. Modelling is done by using element type

BEAM188andtheelementtypeofconcreteSOLID186.Fig-1 showsthemodelofpcsbeam.

2.1.1 Meshing

loading

Prefabricatedcageforbeamismodelledusinghexahedral whichisa20-nodedmesh.Programcontrolledcoarsemesh is adopted for meshing the beams. The mesh size 40 mm. Load is applied as displacement of 10mm according to displacement convergence method.Theloadingis applied 300mmawayfromboththesupports.

2.2 Analysis

Analysisiscarriedouttostudytheflexuralperformanceof prefabricatedbeamwithdifferentprefabricatedcage

Fig-1:Modelofprefabricatedcageforbeam

and

Fig-2:meshingofprefabricatedcageforbeam

Fig-3:Loadingofprefabricatedcageforbeam

Deformation

Deformation

Deformation

Deformationof

Fig-3:Deformationdiagram

2.3 Result and discussion

The result obtained from the Nonlinear static structural analysis prefabricated cage like T3 80x160x3mm, T4 80x160x4mm, T5 80x160x5mm, T6 80x160x6mm are comparedwithconventionalRCC.Forthatloaddeformation curveistakenforeachmodel.

Table-1: Propertiesofprefabricatedcageforbeams

Stirrups

Longitudinal reinforcement

Model

Note:Allunitsareinmillimetre.

Table2showsthereinforcementdetailsofthemodels.Astareaoftensionsteel,Asc-areaofcompressionsteel.theyare given in the table from T4 to T6 their Ast and Asc are 128,150,168 mm^2 respectively which is higher than the conventionalRCCbeam113.04mm^2.T4,T5,T6satisfies theminimumandthemaximumAsrequirements.

DeformationofconventionalRCC

ofT380x160x3mm

ofT480x160x4mm

ofT580x160x5mm

T680x160x6mm

Table -3: Comparisonofresults

Note: a* – area of stirrups, t*- thickness, l*-length, Def*deformation, b*-breadth. All the dimensions are in millimetres

Theloadanddeflectionobtainedarecompared.TheTable 6.3showsthecomparisonofresults

Chart-1:Loaddeflectioncomparison

FromthestudyfindingouttheoptimumthicknessasT6 The thickness varied from 3 to 6, among this T6 shows better performance compared with conventional RCC. Since the maximumloadanddeflectionwasobtainedforthespecimen T680x160x6mmtheoptimumvalueforDis31.03mmand themaximumloadcarryingcapacityis54.22kN.Fromthe studyofimplementingprefabricatedcageforbeamsinstead ofconventionalRCCbeam,itwasfoundthat,Loadcarrying capacity was increased by 8.5%. T6 performs better than RCC,whencomparing with itsarea ofsteel reinforcement anditsweight.Theareaoflongitudinalsteelreinforcement is 452.16 for conventional RCC beam and for T6 it is 336 mm^2. Hence the steel reinforcement is lesser in T 6 and showsbetterperformance.TheweightofmainbarforRCC

Table -2: Reinforcementdetailsofmodels

beamis3.6kg,forT6is2.6kg,theweightisalsolesserwhen itcomparedwiththeRCC.

3. SHEAR CONFINEMENT EFFECT OF THE PCS IN BEAM

shear confinement effect of prefabricated Cage for beam, taking the optimum thickness as 6 mm from the above result. And finding the shear confinement effect using the patternelliptical,tringle,diamond,doublespiral(DS),single spiral (SS), then finding the better performed one in comparison with conventional RCC beam. The different models used are elliptical 80x160x6mm, triangle 80x160x6mm,diamond80x160x6mm,DS80x160x6mm,SS 80x160x6mm. For single spiral selecting 4 models with varyingstirrupwidth(20,30,40,50mm)

3.1 Modelling

PrefabricatedbeamcageismodelledinANSYSsoftwarewith differentspecimendimensionslikeelliptical80x160x6mm, triangle 80x160x6mm, diamond 80x160x6mm, DS 80x160x6mm,SS80x160x6mm.Singlespiral80x160x6mm withvaryingbreadthoftheconfinementsuchasSS10x20x6 mm,SS10x30x6mm,SS10x40x6,SS10x50x6mm.8beams aremodelled.

3.1.1 Meshing and loading

Prefabricatedcageforbeamismodelledusinghexahedral which is a 20-noded mesh. Programme controlled coarse meshisadoptedformeshingthebeams.Themeshsize40 mm.Loadisappliedasdisplacementof10mmaccordingto displacementconvergence method.Theloadingis applied 300mmawayfromthesupport

3.2 Analysis

Analysisiscarriedouttostudytheflexuralperformanceand shear confinement effect of prefabricated beam with differentcuttingshape.Nonlinearstaticstructuralanalysisis carried out in ANSYS software. Deformation and load carryingcapacityisstudied.Thedeformationdiagramsare showninFig4

DS80x160x6mm

SS80x160x6mmwithStirrupwidth20mm

elliptical80x160x6mm

SS80x160x6mmwithStirrupwidth30mm

triangle80x160x6mm

diamond80x160x6mm

SS80x160x6mmwith SS80x160x6mmwith

SS80x160x6mmwithStirrupwidth50mm

ConventionalRCCbeam

3.3

The result obtained from the Nonlinear static structural analysis prefabricated cage like elliptical 80x160x6mm, triangle 80x160x6mm, diamond 80x160x6mm, DS 80x160x6mm,SS80x160x6mm.Singlespiral80x160x6mm withvaryingbreadthoftheconfinementsuchasSS10x20x6 mm,SS10x30x6mm,SS10x40x6,SS10x50x6arecompared withconventionalRCCinordertofindwhichcuttingshape has more confinement effect. For that load deformation curve is taken for each model. The load and deflection obtained are compared with conventional RCC beam. According to the result obtained from objective 1 the optimumthicknessistaken(T6).TheTable6.3showsthe comparisonofresultsandFig.6.5showscomparisonofload deflectioncurve.

Fig-4:Deformationdiagram

Result and discussion

Table-4: Propertiesofprefabricatedcageforbeams

Table-5: Comparisonofresults

Chart-1:Loaddeflectioncomparison

Fromtheeffectofdifferenttypeofconfinementstudyusing different cutting shape on prefabricated cage by using optimum thickness, it was found that, Elliptical, triangle, diamond among these three-shape diamond gives the effective performance with 35.3 % load increase in the confinementstudy.Loadcarryingcapacitywasincreasedby 35.3 % for diamond cutting shape compared with conventionalRCC Loadcarryingcapacitywasincreasedby 2.7%forellipticalcuttingshape.Spiralconfinementstudyof double and Single spiral confinement, load capacity is slightlydecreasefromtheconventionalRCC beam.ForDS andSSdeformationcapacityisincreasedsothattheductility performance increases. Ultimate deflection capacity increasedinthespiralconfinementwhenthebreadthofthe confinement increases to 20,30m40,50 mm. Deflection capacity of 79.42% increases for single spiral 60x50 comparedwithconventionalRCCbeam.

4. CONCLUSIONS

Prefabricatedcageforbeamswithdifferentcagethickness anddifferentcuttingshapearemodelledandanalysed.The comparison of prefabricated cage for beams are studied. Shear confinement effect of different cutting shapes are analysed by ANSYS software and obtain the load v/s deformationbehaviour.

• ComparedtothestandardRCCbeam,theprefabricated cage for beam with a cage thickness of 6 mm demonstratesgreaterloadcarryingcapacity.Sincethe specimenT680x160x6mmachievedtheultimateload anddeflection.Theidealdeflectionvalueis31.03mm, andtheidealloadis54.22kN.

• For a conventional RCC beam, the longitudinal steel reinforcement area is 452.16 mm^2, while for a T6 beam, it is 336 mm^2. As a result, T6 has less steel reinforcementandperformsbetter.

• Elliptical,triangular,anddiamondamongthesethreeshapediamonddeliverstheeffectiveperformancewith a 35.3% load increase in the confinement study, according to the results of the confinement study utilizingthebestthicknessandvariouscuttingshapes onaprefabricatedcage.

• The load capacity of double and single spiral confinements is slightly lower than that of a conventionalRCC beam. Deformation capacity is improved for DS and SS, improving ductility performance. When compared to a conventional RCC beam,thesinglespiral60x50'sdeflectioncapacityrose by79.42%.

• According to the study, the diamond model and T6 prefabricatedcageperformbetterthanthetraditional RCCintermsofflexuralstrength.

REFERENCES

[1] AbdulkadirGulec,M.MetinKoseb,M.Tolga“Ananalysis of the usability of prefabricated cage-reinforced compositebeamswithself-compactingandlightweight concreteunderflexuralloads”.(2020)

[2] AbdulkadirGulec,Mehmet Metin Kose,Mehmet Tolga Gogus “Experimental investigation of flexural performanceofT-sectionprefabricatedcagereinforced beamswithself-compactingconcrete”(2021)

[3] ChrisG.Karayannis,ConstantinE.Chalioris“Sheartests of reinforced concrete beams with continuous rectangularspiralreinforcement”(2013)

[4] MahdiMomeni,JohanReleforsAbubakarKhatry,Lars Pettersson, Alessandro Papadopoulos, Thomas Nolte “Automatedfabricationofreinforcementcagesusinga robotizedproductioncell”(2013)

[5] Yu-ChenOu,Jhe-YanLi,HwasungRohc,“Shearstrength of reinforced concrete columns with five-spiral reinforcement”(2021)

[6] MurtadaS.Mohsin,NameerA.Alwash,MohammedM. Kadhum “Structural behavior of reinforced concrete beamswithoutofplanepart”(2021)

[7] ChithraRethnasamya,ThenmozhiRajagopalb,Hareesh Muthuraj“Bendingbehavior,deformabilityandstrength analysis of Prefabricated Cage Reinforced Composite beams”(2013)

[8] Seung-HyeonHwang,Keun-HyeokYang,Yong-SooChoi, Seung-JunKwond“Axialandflexuralperformancesof columnsrestoredafterseveredamage“(2021)

[9] Song Xia a,b , Xinyi Wei , Chang He , Faxing Ding , WeizhenZhangd,JiayeWue,SenYang“Performanceof stirrup-confined concrete-filled steel tubular stub columns under axial loading: A further investigation” (2022)

[10] Worakarn Anuntasena, Akhrawat Lenwari, Thaksin Thepchatri “Axial compression behavior of concreteencasedcellularsteelcolumns”2020