Seismic optimization of horizontally irregular buildings with floating column using dampers

International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

Volume: 09 Issue: 07 | July 2022 www.irjet.net p ISSN: 2395 0072

Seismic optimization of horizontally irregular buildings with floating column using dampers

Thasfia Jamal1, Jinu V R2

1PG student, Dept of Civil Engineering, KMEA Engineering College, Kerala, India

2Asst.Professor, Dept. of Civil Engineering, KMEA Engineering College, Kerala, India ***

Abstract – Nowadays multistory buildings are constructed for the purpose of residential, commercial, etc with open ground story. For the purpose of parking, usually ground story is kept open. Buildings which have discontinuity of columns and buildings having columns which transfer load to the beam in lateral direction are called as floating column. Here, the seismic analysis of horizontally irregular buildings with floating column is done. It is then optimized using dampers.

Key Words: Seismic optimisation, Floating columns, Diaphragm discontinuity, Re entrant corners, Etabs, Viscous dampers, Time history analysis

1. INTRODUCTION

Indiaisadevelopingcountry,whereurbanizationisatthe faster rateinthecountry.Asa partofurbanizationmulti story buildings with architectural provisions are constructed. These necessities are nothing but soft story, floating column, hefty load, the lessening in stiffness, etc. mostofthemultistoriedbuildingshavingopengroundstory as an obligatory feature to afford parking area, reception lobbiesandforotherarchitecturalneeds.Nowadaysmulti story building construction for residential, industrial or commercialpurposehasbecomeacommonfeature.These multi story building need more parking or open spaces below.Thisopengroundstoryconceptleadstointerruption of columns called floating columns These are more advantageousinurbanareaswherespaceisanissue.

In this paper, effect of floating column on multi story building has been studied and optimized by viscous dampers. The results on structures with floating column having horizontal irregularities have been compared. Various parameters such as displacement, base shear and time period are discussed. The material properties and section properties considered for analysis are shown in Table1&2.

1.1 Floating Column

Infloatingcolumntransferofloadtothecolumnbelowitby the beam. The transfer of load in floating column changes fromverticaltohorizontalwithintheintermittentframe.In many cases these columns are chosen specially above

bottom floor. Thus more open spaces is offered within groundfloorwhichcanbeusedforauditoriumorparking intention. Thus floating column is additionally used in construction practice and it is avoided due to excess of beams.Tomaintainthestabilityofbuildingthejointamong beamandfloatingcolumnaretreatedascritical.Maincause of collapse of this type of structure is the failure of large beam column specimens occurs in the joint in concrete moment resisting frame. The geometry of the considered modelisshownintable3.

2. SCOPE

Thestudyislimitedtoimprovingtheseismicperformanceof horizontally irregular structures such as plan irregular, diaphragmdiscontinuityandre entrantcornerirregularity withfloatingcolumnusingviscousdampers.ETABSsoftware isused.

3. METHODOLOGY

Themainobjectiveofthisresearchistostudytheseismic performanceofaregularandirregularmulti storeybuilding with floating column with parameters like displacement, timeperiodandbaseshearandtooptimizefloatingcolumn buildings with viscous dampers. Three dimensional mathematical modelling of floating column buildings with ETABSsoftware.Non lineardynamicanalysis(timehistory analysis)wascarriedouttostudytheseismicperformance ofthebuilding.

4. MODELLING

Nine building models having G+9 story are created and analyzed

MODEL 1 Regular building with floating column in the middleandtheendsofstory1inbothdirection.

MODEL 2 Irregular building having diaphragm discontinuity with floating column in the middle and the endsofstory1inbothdirection.

MODEL 3- Irregular building having diaphragm discontinuity with floating column in the middle and the ends of story 1 in both direction with strut introduced at story2.

International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

Volume: 09 Issue: 07 | July 2022 www.irjet.net p ISSN: 2395 0072

MODEL 4 Irregular building having diaphragm discontinuity with floating column in the middle and the endsofstory1inbothdirectionwithdamperintroducedat story2.

MODEL 5- Irregular building having diaphragm discontinuity with floating column in the middle and the ends of story 1 in both direction with strut introduced at story2anddamperintroducedatallotherstoriesexcept1 and2.

MODEL 6 Irregularbuildinghavingreentrantcornerwith floatingcolumninthemiddleandtheendsofstory1inboth direction.

MODEL 7 Irregularbuildinghavingreentrantcornerswith floatingcolumninthemiddleandtheendsofstory1inboth directionwithstrutintroducedatstory2.

MODEL 8 Irregularbuildinghavingreentrantcornerswith floatingcolumninthemiddleandtheendsofstory1inboth directionwithdamperintroducedatstory2.

MODEL 9 Irregularbuildinghavingreentrantcornerswith floatingcolumninthemiddleandtheendsofstory1inboth direction with strut introduced at story 2 and damper introducedatallotherstoriesexcept1and2.

Fig -2:3Dviewbyfloatingcolumninthemiddleandthe endsofstory1inbothdirection.(Model1)

Fig 1:Planbyfloatingcolumninthemiddleandtheends ofstory1inbothdirection.(Model1)

Fig -3:Planbyfloatingcolumninthemiddleandtheends ofstory1inbothdirectionhavingdiaphragm discontinuity(Model2)

Fig 4:3Dbyfloatingcolumninthemiddleandtheendsof story1inbothdirectionhavingdiaphragmdiscontinuity (Model2)

International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

Volume: 09 Issue: 07 | July 2022 www.irjet.net p ISSN: 2395 0072

Fig -5:3Dviewbyfloatingcolumninthemiddleandthe endsofstory1inbothdirectionhavingdiaphragm discontinuitywithstrut.(Model3)

Fig -8:Planbyfloatingcolumninthemiddleandtheends ofstory1inbothdirectionhavingreentrantcorners (Model6)

Fig -6:3Dviewbyfloatingcolumninthemiddleandthe endsofstory1inbothdirectionhavingdiaphragm discontinuitywithdamper.(Model4)

Fig 9:3Dbyfloatingcolumninthemiddleandtheendsof story1inbothdirectionhavingreentrantcorners(Model 6)

Fig 7:3Dviewbyfloatingcolumninthemiddleandthe endsofstory1inbothdirectionwithstrutanddamper. (Model5)

Fig 10:3Dbyfloatingcolumninthemiddleandtheends ofstory1inbothdirectionhavingreentrantcornerswith strut(Model7)

International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

M20gradeconcrete

Column(1F 3F)

Column(4F 6F)

550×550mm M25gradeconcrete 450×450mm

M25gradeconcrete

Column(7F 9F) 350×350mm M25gradeconcrete Slab 130mm M20gradeconcrete

Fig 11:3Dbyfloatingcolumninthemiddleandtheends ofstory1inbothdirectionhavingreentrantcornerswith damper(Model8)

Deadload 1.5kN/m2 Liveload 2.5kN/m2 Rooflive 1kN/m2

Table 3: Geomtryofmodels

No.of storeys Xdirection baywidth Ydirection baywidth Heightof bottom storey

Heightof storey 9 4.5 4.5 4 3

4. RESULTS AND DISCUSSION

Table -3: Comparisonvaluesofdisplacement,baseshear andtimeperiod

Fig 11:3Dbyfloatingcolumninthemiddleandtheends ofstory1inbothdirectionhavingreentrantcornerswith strutanddamper(Model9)

Table 1: Materialpropertiesofmodels

Properties Values

Displacement Baseshear Time period

X Y X Y X Y

FCM&E 200.31 200.31 38863.9 38863.9 18 18

DCFC M&E 188.6 188.6 30624.5 30624.5 17 17

DCFC M&ES 121.5 121.5 33533.2 33533.2 1.4 1.4

DCFC M&ED 120.3 120.07 33279.7 33364.7 14 14

25000MPa

Characteristiccompressive strengthofconcrete,fck 25MPa Yieldstressforsteel,fy 415MPa Elasticmodulusofsteel,Es 20,0000MPa Elasticitymodulusofconcrete, Ec

Table 2: Sectionpropertiesofmodels

Parameters Structurewithfloating columnat1st floor

LengthinX direction 45

LengthinY direction 45

No.ofstoreys Ten(G+9) Beam 400×350mm

DCFC M&E S+D

145.8 145.8 35444.4 35444.4 13 14

REFC M&E 211.4 211.4 19508.5 19508.5 1.7 1.8

REFC M&ES 124.1 124.1 21182.1 21182.1 14 14

REFC M&ED 119.8 120.7 20727.4 20774.2 1.4 14

REFC M&E S+D

168.9 168.9 25120.8 25120.8 12 13

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International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

Fig -11:Comparisonvaluesofdisplacementofmodel 1,2,3,4

Fig -14:Comparisonvaluesofdisplacementofmodel 6,7,8,9

Fig 12:Comparisonvaluesoftimeperiodofmodel1,2,3,4

Fig 15:Comparisonvaluesoftimeperiodofmodel6,7,8,9

Fig 13:Comparisonvaluesofbaseshearofmodel1,2,3,4

Fig 16:Comparisonvaluesofbaseshearofmodel6,7,8,9

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International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056

Volume: 09 Issue: 07 | July 2022 www.irjet.net p ISSN: 2395 0072

3. CONCLUSIONS

This research studied the effect of floating column in horizontally irregular buildings and the optimization by viscous dampers.Atimehistoryanalysishasbeencarried out to study the seismic performance. As a result of the investigationfollowingresultsweremade:



Thereisadecreaseindisplacementandincreasein baseshearofmodelshavingstrutanddamper.



Modelwithdamperonlyshowslowerdisplacement valuesinthecaseofdiaphragmdiscontinuityand reentrantcorner.

Fromoverallresearchitcanbeconcludedthattomakethe building safe from seismic effect, viscous dampers can be providedwhichreducethedisplacementofbuildingscaused byfloatingcolumn.Bythiswaywecanincreasetheuseof floatingcolumn.

REFERENCES

[1] Sreadha A R, C Pany,(2020)Seismicstudyofmultistory buildingusingfloatingcolumn, IJESE, 4,4.

[2] Pradeep D, et.al, (2017)Seismicanalysisofmultistory buildingwithfloatingcolumnusingETABS, ISSN,2,9.

[3] ShivamTyagi, Prof. B S Tyagi, (2018)Seismicanalysis ofmultistorybuildingwithfloatingcolumn, IRJET, 5,5.

[4] S Boopathi Raja, V Preetha, (2017)Studiesoneffectof structural irregularities on seismic performance of reinforcedconcretebuilding, IJTSRD,1,6.

[5] Prof. SujeetPatil, et.al, (2019)Seismicanalysisofplan regularandirregularbuildings, IRJET,6,5

2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal