analyzation of multistoried building strengthening in

International Journal of Science Engineering and Advance Technology,IJSEAT, Vol. 5, Issue 2

ISSN 2321-6905February -2017

www.ijseat.com, 1*Corresponding Author Page 227

Analyzation of Multistoried Building Strengthening in Seismic Regionwithin fills and Using Etabs

Kunche Bhavana1*,P.M.Lavanya2

M.Tech(Student)1,Assistant professor2 in Dept.of Civil engineeringkakinada institute of engineering & technology-II,korangi

ABSTRACT

Current building codes for seismic design andevaluation in Europe and American componentexecution based criteria that involve the estimation ofinelastic reaction of the building because of seismic.These seismic requests can be precisely decide byutilizing strategies for nonlinear time history analysis.Streamlined strategies in view of nonlinear staticanalysis, known as sucker analysis technique andstraight element analysis, known as time history analysisstrategy, have been produced by a few controls to fulfillthe execution based criteria for seismic design andevaluation of buildings. This proposal managesmultistory buildings with open (soft story) ground floorare inalienably defenseless against crumple because ofseismic burdens, their developments is still boundless increate countries. Social and utilitarian need to give autoparking spot at ground level far exceeds the noticeagainst such buildings from designing group. In thisreview, 3D expository model of multistory buildinghave been producing for multistoried building modeland breaking down utilizing auxiliary analysisinstrument 'ETABS'. The investigative model ofbuilding incorporates immeasurably vital segments thatimpact the mass, quality, solidness of the structure.Numerical outcomes for the accompanying seismicrequests considering the inelastic conduct of thebuilding, malleability coefficients of structures.

Keywords: soft story, ground soft, infill, mass, quality,solidness, inelastic conduct, float proportion, flexibilitycoefficients.

I. Introduction

The limit of auxiliary individuals to experience inelasticdisfigurements represents the basic conduct anddamageability of multi-story buildings amid seismictremor ground movements. Starting here of view, theevaluation and design of buildings ought to be foundedon the inelastic disfigurements requested by quakes,other than the anxieties instigated by the identical staticstrengths as determined in a few seismic directions andcodes. In spite of the fact that, the present practice forseismic tremor safe design is predominantly representedby the limit of auxiliary individuals to experienceinelastic distortions administers the basic conduct anddamageability of multi-story buildings amid quakeground movements. Starting here of view, theevaluation and design of buildings ought to be foundedon the inelastic disfigurements requested by tremors,other than the burdens incited by the comparable staticstrengths as determined in a few seismic controls andcodes. Standards of drive based seismic design, therehave been huge endeavors to consolidate the ideas ofdistortion based seismic design and evaluation into thequake building hone. As a rule, the investigation of theinelastic seismic reactions of buildings is not just helpfulto enhance the rules and code arrangements forminimizing the potential harm of buildings, additionallyimperative to give sparing design by making utilizationof the saved quality of the building as it encountersinelastic disfigurements. In late seismic rules and codesin Europe and USA, the inelastic reactions of thebuilding are resolved utilizing nonlinear static strategiesfor analysis known as the weakling techniques.Execution Based Engineering (PBE) in relationship withexisting ideas of seismic tremor safe design requiresnonlinear analysis to acquire appraisals ofdisfigurements for harm evaluation for various levels ofquakes. In the execution based method, the coveted

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levels of seismic execution for a building for determinedlevels of tremor ground movement are indicated. Theexecution is checked as far as post versatiledisfigurements. ATC-40 gives the Capacity SpectrumMethod for actualizing PBE for buildings. It utilizesNonlinear Static Pushover (NSP) analysis to build upthe limit bend (a plot of base shear Vs rooftopuprooting). In this paper, speculative multistoriedbuildings (i.e., twelve storied and nine storied with infilland with ground soft story) situated in zone V ofmedium soil locales has been broke down and designedfor load mixes given in code and assessed utilizingweakling analysis.

II. Literature Survey

A venture on study for SESIMIC EVALUATION OFMULTISTORIED BUILDING WITH GROUND SOFTSTORY& WITH INFILLS these review I have takenaround 2 unique models of the buildings arecontemplated. The open first story is a critical utilitarianprerequisite of all the urban multi-story buildings, andhenceforth, can't be disposed of. Elective measuresshould be received for this particular circumstance. Thedirt adaptability should be inspected deliberately beforesettling the investigative model of a building. Trialexamination of RC casings with block stone work infilldividers having focal opening subjected to cyclicrelocation stacking was done with a target to look at theexecution of infill workmanship outlines with that ofuncovered edges subjected to turn around cyclicremoval controlled stacking. They reasoned that thenormal starting solidness of an infill RC edge is around4.3times than that of an exposed casing where the brickwork is unreinforced, and around 4.0 circumstances thatof uncovered edge when the stone work is strengthened.From quality perspective it demonstrates that theunreinforced stone work infill outlines had around 70%more prominent quality than exposed edges; the esteemwas around half higher on account of RC infill outlines.Furthermore presumed that the yield relocation of infilled edges is much littler than that of the uncoveredcasing, and consequently demonstrated that the infilloutlines have extensively more noteworthy pliability.Hence, dynamic weakling bends for the buildings areproduced as the best fit bends for the dynamicoutcomes. For every building, the base shear limit isassessed by contrasting the static and element weaklingbends. At that point, the sucker bends together with aregular design reaction range are used to decide the

distortion state at which the seismic requests areassessed for execution evaluation of buildings.Numerical outcomes for the accompanying seismicrequests are demonstrated considering the inelasticconduct of the buildings: rooftop floats, story add up tofloats, bury story float proportions, malleabilitycoefficients and plastic pivot dispersions. The outcomesshow that the seismic requests assessed by applying thesucker methods concur well with the aftereffects of thenonlinear time-history examinations for the multistorysteel and RC buildings in this review. In this manner,these seismic requests are worthy for ordinary designpurposes. When all is said in done, the execution levelof the lower stories in light of the entomb story floatproportions is better for the steel buildings contrastedwith the RC buildings, though the upper stories of theRC buildings experience bring down bury story floats.The plastic pivot disseminations indicate thesignificance of consolidating the impacts of inelasticdisfigurements, which create in the building amid theweakling analysis, through the horizontal load designs.

III. Soft or flexible story

The delicate story abnormality, alludes to the presenceof a building floor that introduces an essentially bringdown firmness than the others, thus it is likewise called:adaptable story. It is generally create unconscientiouslybecause of the end or lessening in number of inflexiblenon-auxiliary dividers in one of the floors of a building,or for not considering on the basic plan andexamination, the confinement to free distortion thatupholds on whatever is left of the floors, the connectionof unbending components to basic segments that werenot initially mulled over. On account of the impactscreated by non-basic segments on the seismic executionof the building, the term non-deliberately nonstructuralhas been doled out to these parts since the finish of the1980's (Guevara, 1989). Table 12.3-2 in the ASCE/SEI7-10 record, (p. 83) characterizes delicate story asinconsistency sort 1. On the off chance that the delicatestory impact is not predicted on the auxiliary outline,irreversible harm will for the most part be available onboth the basic and nonstructural segments of that floor.This may bring about the nearby fall, and at times eventhe aggregate crumple of the building.




The least more adaptable part, in the wayof compel transmission, at first story may make a basiccircumstance amid a tremor; the firmness intermittencebetween the first and the second stories may bring aboutnoteworthy basic harm, or even the aggregate crumpleof the building. A standout amongst the most widelyrecognized cases of delicate story can be seen on thealleged "Open floor" in the primary story of present dayprivate structures. The basic components arehomogenously dispersed all through the building,however the flats are situated on the upper floors withnumerous workmanship dividers, while the least floor isleft absolutely or halfway free of segments for stoppingvehicles and for social ranges that require wide spaces.On account of twofold stature first delicate stories,sections are exceptionally adaptable not just because ofthe aggregate or incomplete nonappearance of dividershowever therefore of their altogether more noteworthytallness in connection with those from the upper floors.This setup is one of the trademark models of currentoutline for office structures, lodgings and clinics, inwhich the entrance for overall population has anawesome significance. . This design is likewiseextremely basic in blended utilize structures, in whichthe urban code requires that the lower floors are of amore noteworthy stature keeping in mind the end goal tosuit shops with mezzanines for capacity. As a variationof this arrangement, we can discover the utilization ofsegments of various statures in a side of the working togive more significance to that space. Fig. 2.4 shows twocases of present day structures with twofold tallness firstdelicate story arrangement. In a large portion of theseismic tremors that happen in contemporary urbanareas, there are dependably instances of given waydelicate first story. Fig. 2.5 presents two cases of lateextreme harm because of delicate first story ofinconsistency in L'Aquila seismic tremor, Italy in 2009,and in the private complex "San Fernando" of minimal

effort lodging in Lorca, Spain in 2011, where toward thestarting the structures didn't indicate obvious seriousharm, however, every one of the structures of this mindboggling that had delicate first story, were pulled down.The secured walkway, or arcade, is a setup got fromdelicate story inconsistency. It is a colonnade, similar toan order, in the principal story of the front façade that isnormal for structures on business roads. It is a typicalvariety of abnormality in the dispersion of theresistance, solidness and mass of structures, which islikewise incorporated into UZR of contemporary urbancommunities as a legacy of the medieval city.

Another adaptation of the secured walkways is thetwofold tallness sort. The majority of the UZRincorporate this setup in blended utilize structures(business and private), which permits to have twofoldtallness first stories, a mezzanine for capacity andtwofold stature grandstand confronting the securedwalkway, with a specific end goal to demonstrate thestock. The utilization for this situation of extremely thinsections, and in addition the utilization of twofoldstature discharge spaces, makes an unpredictablecirculation of the responsive mass, resistance andfirmness.

Soft story also exists at intermediate floors. It is atypical configuration of massive low cost housingprograms which follow the patterns of the United'Habitation in Marseilles of Marseille (1947-1952) byLC. The concept which prevailed on the layout of thissort of isolated building was the self- sufficiency, as theresidence features were included, communal facilities,such as, a library, nursery school, film club, recreationalareas, businesses and others; some of which neededwide available spaces therefore an entire floor or a greatsection of it was left with no walls.




Soft story failures

IV. Seismic analysis procedures

Seismic analysis is a subset of structural analysis and isthe calculation of the response of a building structure toearthquakes .A building has the potential to wave backand forth during an earthquake .This is called thefundamental modes and it is the lowest frequency ofbuilding response. Most of the buildings however havehigher modes of response, which are uniquely activatedduring earth quakes.

Safety Evaluation of Reinforced Concrete Buildings

Safety against collapse of reinforced concrete is usuallydefined in terms of its ductility ratios. The design ofreinforced concrete structures is performed by usingresistance smaller than the one required for the systemto remain elastic under intense ground shaking. Then,the seismic codes implicitly cause structural damagesduring strong earthquake motions and the design relieson the capacity of the structures to undergo largeinelastic deformations and to dissipate energy withoutcollapse. This design methodology is used by all designstandards including IS 1893.

SEISMIC VULNERABILITY

The vulnerability of a building subjected to anearthquake is dependent on seismic deficiency of thatbuilding relative to a required performance objective.The seismic deficiency is defined as a condition that

will prevent a building from meeting the requiredperformance objective. Thus, a building evaluated toprovide full occupancy immediately after an event mayhave significantly more deficiencies than the samebuilding evaluated to prevent collapse.

Depending on the vulnerability assessment, a buildingcan be condemned and demolished, rehabilitated toincrease its capacity, or modified so that the seismicdemand on the building can be reduced. Thus, structuralrehabilitation of a building can be accomplished in avariety of ways, each with specific merits andlimitations related to improving seismic deficiencies.

HOW DO BUILDINGS RESIST EARTHQUAKEFORCES?

As a building responds to ground motions produced byan earthquake, the bottom of the structure movesimmediately, but the upper portions do not because oftheir mass and inertia. Figure-3.4 shows the base of abuilding moving while the upper part lags behind.

The horizontal force, or base shear, created by groundmotion resulting from an earthquake must be resisted bythe building. The more the ground moves, or the greaterthe weight of the building, the more force must beresisted by the building. When an architect or engineerdesigns a building, he or she must determine themaximum force a building might have to resist in thefuture. Buildings are always designed to handle normalvertical and lateral forces. However, once you introducethe possibility of an earthquake, a building must bedesigned for extraordinary horizontal or lateral forces.The horizontal (lateral) forces associated with anearthquake can be thought of as a lateral force applied toeach floor and to the roof of a building. Figure 3.7.3shows the vertical and horizontal forces on a buildingduring an earthquake. Panel (a) shows the direction ofgravitational forces on a building, panel (b) shows thehorizontal force of seismic waves, and panel (c) showsthe combined forces of gravity and an earthquakeapplied to the floors and roof of a building.




Fig -behaviour of building in ground acceleration

Horizontal forces accumulate along the floors and roofand then are distributed through the vertical supportsinto the foundation. A structural engineer must design abuilding so that lateral forces are distributed throughoutthe building without a break. Several structural systems,such as floors, walls, and columns, may be used in newbuildings to reduce the effects of earthquakes andassociated natural disasters.

Fig –forces acting on the building during groundexcitation

STIFFNESS:

A building is comprised of both unbending andadaptable components. For instance, shafts andsegments might be more adaptable than solid dividers orboards. Less inflexible building components have amore prominent ability to assimilate a few cycles ofground movement before disappointment, as opposed tosolid components, which may bomb unexpectedly andsmash abruptly amid a seismic tremor. Tremor drivesconsequently concentrate on the stiffer, inflexiblecomponents of a building. Thus, structures must be builtof parts that have a similar level of adaptability, so thatone component does not twist excessively and exchangethe vitality of the quake to less pliable When the tremorstruck, the more drawn out, more adaptable sections atthe front of the building passed the seismic tremordrives on to the short, stiffer segments in the back asopposed to dispersing the powers similarly among themajority of the segments. Diversion, the degree to whicha basic component moves or curves under weight,assumed a noteworthy part. The more drawn outsections basically diverted or bowed without splitting.The short segments, in this way, were overpowered andsplit.

Fig showing long and short columns

V. Analytical Modelling

Most construction standards endorse the strategy forinvestigation in light of whether the building iscustomary or sporadic. All the codes recommend theutilization of static investigation for symmetric andchose class of customary structures. For structures withsporadic designs, the codes propose the utilization ofelement investigation strategies, for example, reactionrange technique or time history examination.

Seismic codes give diverse strategies to do parallel loadexamination, while doing this investigation infilldividers display in the structure are ordinarilyconsidered as non auxiliary components and theirnearness is generally overlooked while investigation andoutline. However despite the fact that they areconsidered as non-auxiliary components, they have atendency to connect with the edge when the structuresare subjected to parallel burdens.

In the present review horizontal load investigationaccording to the seismic code for the accompanying sortof structures, exposed edge, full infill, base delicatestory, focal center divider, shear divider in x and yheading and alongside focal center divider, shear dividerin corners and alongside focal center divider iscompleted and an exertion is made to concentrate theimpact of seismic loads on them and in this wayevaluate their seismic powerlessness by performingweakling examination. The investigation is doneutilizing etabs examination bundle.

DESCRIPTION OF THE SAMPLE BUILDING

The plan layout for all the building models are shown infigures

SYMMETRIC BUILDING MODELS:




Model 1: Twelve storied Building with full infillmasonry wall (230 mm thick) in all story’s.

Model 2: Twelve storied Building (ground story) nowalls in the soft storey and full brick infill masonrywalls (230 mm thick) in the upper story’s.

Model 3: Nine storied Building with full infill masonrywall (230 mm thick) in all story’s

Model 4: Nine storied Building (ground story) no wallsin the first storey and full brick infill masonry walls(230 mm thick) in the upper story’s.

Figure: Plan Layout

Figure: Plan Layout

Fig: Elevation of twelve storied Building Model 1(full infill)

Fig: Elevation of twelve storied Building Model 2(ground soft)

Fig: Elevation of nine storied Building Model 3 (fullinfill)

Fig: Elevation of nine storied Building model4(ground soft)

Manual calucuation:




Natural Periods And Average Response AccelerationCoefficients:

For Twelve-storied Frame Building:

Fundamental Natural period,longitudinal and transverse direction,Ta=0.075*360.75=1.102sec

For medium soil sites, Sa/g =1.36/T=1.36/1.102=1.234

For twelve-storied brick infill’s buildings:

Fundamental natural period longitudinal direction,Ta=0.09/√25=0.018 sec

For medium soil sites, Sa/g = 1+15T=1.27

Fundamental Natural period, transverse direction,Ta=0.09/√20=0.0045 sec

For medium soil sites, Sa/g = 1+15T=1.067

Design horizontal seismic coefficient,


g

Sax

R

Ix

ZAh 2

Ah= (0.36/2) x (1.5/5) x 2.060 =0.11124 in longitudinaldirection.

Ah= (0.36/2) x (1.5/5) x 2.11 =0.1139 in transversedirection.

Manual calucuation:

Natural Periods And Average Response AccelerationCoefficients:

For nine-storyed Frame Building:

Fundamental Natural period,longitudinal and transverse direction,

Ta=0.075*360.75=1.102sec

For medium soil sites, Sa/g =1.36/T=1.36/1.102=1.234

For nine-storied brick withoutinfill’s walls in buildings:


g

Sax

R

Ix

ZAh 2

Ah= (0.36/2) x (1.5/5) x 1.234=14.9931

Table (A) : Deign Seismic Based Shear for twelvestoried buildings

Table 1: Distribution of Lateral Seismic Shear forcefor twelve storiedbuilding for Model 1

Level (Qi)x(KN) (Qi)y (KN)

12 1840.97 1840.97

11 3877.20 3877.20

10 5578.70 5578.70

9 6889.70 6889.70

8 7977.55 7977.55

7 8758.57 8758.57

6 9400,12 9400,12

5 9790.63 9790.63

4 10097.46 10097.46

3 10236.46 10236.46

2 10264.82 10264.82

1 10264.82 10264.82

Table 2 : Distribution of Lateral Seismic Shear forcefor twelve storied building for Model 2


12 1820.01 1820.01

11 3855.23 3855.23

10 5526.22 5526.22




9 6802.23 6802.23

8 7932.24 7932.24

7 8721.57 8721.57

6 9320.02 9320.02

5 9784.55 9784.55

4 9984.22 9984.22

3 10085.21 10085.21

2 10095.97 1095.97

1 10095.97 1095.97

Table (B) : Deign Seismic Based Shear for ninestoried buildings

Table 3 : Distribution of Lateral Seismic Shear forcefor nine storied building for Model 3

Table 4 : Distribution of Lateral Seismic Shear forcefor nine storied building for

Model 4


9 1701.86 1701.86

8 3423.52 3423.52

7 4808.75 4808.75

6 5798.21 5798.21

5 6530.40 6530.40

4 6945.98 6945.98

3 7183.45 7183.45

2 7282.39 7282.39

1 7282.39 7282.39

Figure: Shear diagram for twelve storied Model 1along longitudinal and transverse direction

VI. Results and Discussions

Most of the past studies on different buildings andunsymmetrical buildings have adopted idealizedstructural systems without considering the effect ofmasonry infill and concrete shear walls. Although thesesystems are sufficient to understand the generalbehavior and dynamic characteristics of unsymmetricalbuildings, it would be interesting to know how realbuildings will respond to earthquake forces. For thisreason hypothetical buildings, located on level groundhaving similar ground floor plan have been taken asstructural systems for the study.


9 1721.07 1721.07

8 3523.14 3523.14

7 4879.75 4879.75

6 5892.15 5892.15

5 6621.08 6621.08

4 7107.03 7107.03

3 7350.00 7350.00

2 7451.24 7451.24

1 7451.24 7451.24




In this chapter, the results of the twelve selectedbuildings are presented and discussed in detail. Theresults are includes of all different building models andthe response results are computed using the responsespectrum and pushover analysis. The analysis anddesign of the different building models is performed byusing ETABS analysis package.

The results of natural period of vibration, base shear,lateral displacements and story drifts, ductility,reduction factor & overall performance for the differentbuilding models for each of the above analysis arepresented and compared. An effort has been made tostudy the effect of in fills, concrete core wall andvertical irregularities and mass irregularities in seismicanalysis.

TABLE 5.1 DISPLACEMENTS OF 12 STOREYINFILL STRUCTURE IN MM.

0

2

4

6

8

1 0

1 2

0 2 4 6 8 1 0 1 2 1 4 1 6

Y A x is T itle

X Ax

is Tit

le

B C

Fig displacement of linear static analysisof 12thstorey buildings in x – direction.

0

2

4

6

8

10

12

0 2 4 6 8 10 12 14 16 18

Y Axis Title

X Ax

is T

itle

B C

Fig displacement of linear static analysis of 12thstoreybuildings in y – direction.

DISPLACEMENTS

STOREYNO’S.

EQUIVALENTSTATIC

METHOD

RESPONSESPECTRUMMETHOD

PUSH OVERANALYSIS

UX UY UX UY UX UY

STORY12 15.6774 16.8968 11.1648 11.9447 78.3627 48.0587

STORY11 14.8334 15.8834 10.6235 11.2863 73.8908 44.4746

STORY10 13.7835 14.6708 9.9596 10.5086 69.0147 40.7936

STORY9 12.5598 13.2915 9.1799 9.6202 63.7169 37.0101

STORY8 11.2031 11.7879 8.2994 8.6381 57.9746 33.1076

STORY7 9.7531 10.2011 7.3347 7.5809 51.7636 29.0399

STORY6 8.2477 8.5715 6.3039 6.4687 45.0679 24.7732

STORY5 6.723 6.9376 5.2264 5.3225 37.9316 20.4227

STORY4 5.2128 5.3361 4.123 4.1649 30.4994 16.033

STORY3 3.7485 3.8014 3.0157 3.0194 22.7503 11.5995

STORY2 2.3598 2.3666 1.9293 1.9123 15.0849 7.4868

STORY1 1.0654 1.0536 0.8834 0.8649 7.6206 3.8314




0

2

4

6

8

10

12

0 2 4 6 8 10 12

Y Axis Title

X A

xis

Title

B C

Fig displacement of linear dynamic analysis of12thstorey buildings in x – direction.

0

2

4

6

8

10

12

0 2 4 6 8 10 12 14

Y Axis Title

X A

xis

Title

B C

Fig 5.4 displacement of linear dynamic analysis of12thstorey buildings in y – direction.

Performance point

The performance point of the building models inlongitudinal and transverse directions are shown infigure 5.25 to 5.32 as obtained from ETABS. Thevalues of seismic coefficients Ca and Cv for zone-V aretaken from the table 5.11.

Seismic Coefficient, CA

SoilZone II(0.10)

ZoneIII(0.16)

ZoneIV(0.24)

Zone V(0.36)

Type I 0.12 0.19 0.28 0.37

Type II 0.15 0.23 0.31 0.41

Type III 0.23 0.31 0.35 0.36

Seismic Coefficient, CV

Type I 0.17 0.26 0.37 0.52

Type II 0.23 0.34 0.46 0.60

Type III 0.34 0.53 0.72 0.91

Table-5.11: Interpolated values of SeismicCoefficient (CA and CV) for the soil type

Fig.Performance point of twelve storied buildingModel 1 along longitudinal direction

Figure: Performance point of twelve storied buildingModel 1 along transverse direction

VIII. CONCLUSION

Based on the results obtained from different analysis forthe various building models, the following conclusion isdrawn.

1. The codal time period and analytical timeperiod do not tally each other because codalcalculation is depends on empirical formula




2. Underestimation of design base shear in case ofbare models as compared to the infill modelsthe design of base shear increases withincreases in mass and stiffness of masonryinfill wall and vice versa.

3. Infill panel increases the lateral stiffness of thebuilding, measured in terms of the roofdisplacement there by reducing displacementsin all storey levels compared to bare framemodels.

4. As model spectral analysis more suitable forproblems involving in the structural design ofnew structures ,while pushover analysis ismore indicated for assessing the sesmicvulnerability of existing structures.

5. From the analysis it came to know that foranalysing the seismic evolution on the structurethrough E tabs we have to do both the responsespectrum analysis and pushover analysis for astructure as for the push over analysis tocapture dynamic effects we should calculateusing through response spectrum analysis only,and at this displacement we assess theperformance of the structure.

6. It came to know that with masonry infill wallsthroughout the structure and having soft storeyit may easily vulnerable mainly in seismicregions even we came to know these by themodels As compared to Model 1have adisplacement of 3.75% model 2 have adisplacement of 6.64%, As compared to Model3 have a displacement of 5.42% model 4 havea displacement of 10.16%

7. It is essential to consider the effect of masonryinfill for the seismic evaluation of movementresisting RC frames especially for theprediction of its ultimate state. Infills increasethe lateral resistance and initial stiffness of theframes they appear to have a significant effecton the reduction of the global lateraldisplacement. Infills having no irregularity inelevation having beneficial effects onbuildings. In infilled frames with irregularities,such as ground soft storey, damage was foundto concentrate in the level where thediscontinuity occurs.

8. The displacements and inter story drift ratios atedge of the buildings are compared at differentlevels of the building deformation. the resultsare drastically changed, at the level belowwhich there is no infill and above which theinfill wall is present(ground soft storey),thestorey drift has a value of 12mm it exceeds thisvalue .As it has The graph associated with thebuilding model-2 and model-4 is less stiff andyields at a lower base shear value than that ofthe other building models.

9. The capacity curve is intersecting the demandcurve of the infill structures which indicatesthat the performance level of the building isgood. The capacity curve and demand curveare intersecting only for infill structures. Theperformance level of the infill structure is goodand whereas the soft story structure is worst

Scope for future study

Further studies can be conducted on high rise buildings(sky-scrapers) by providing more thickness of shearwalls. Studies can be conducted by providing shear wallat various other locations and also by providing dualsystem, which consists of shear wall (or braced frame)and moment resisting frame such that the two systemsare designed to resist the total design force in proportionto their lateral stiffness considering the interaction ofdual system at all floor levels. The moment resistingframes may be designed to independently resist at least25% of design seismic base shear. For better ductilitybeam-column junction study can also be made. Andfurther study an existing building can be considered forevaluation. Where, a preliminary investigation usingFEMA-273 can be done before evaluation of theexisting building using mathematical modelling with thehelp of FEA package and further it can be evaluatedusing Non-Linear Dynamic Analysis and othersoftware’s like sap

This investigation can also be done on Sloping RCCbuildings constructed on hills in hill stations were landis at high cost and it will also attracts the tourists.

Various damping mechanisms and its applications onstructures can also be studied. Studies can also beconducted by modelling the structures having baseisolation system.




REFERENCES

1. Arlekar, N.J., Jain K.S., and Murthy, C.V.R. “SeismicResponse of RC Frame Buildings with Soft FirstStoreys”, Proceedings of the CBRI Golden JubileeConference on Natural Hazards in Urban Habitat, NewDelhi, 1997.

2. Krawinkler, H., and Seneviratna, G.D.P.K. (1998):Pros & Cons of Pushover Analysis of SeismicPerformance Evaluation.

3. Ashraf Habibullah, Stephen Pyle, “Practical three-dimensional non-linear static pushover analysis”Structure Magazsanine, Winter, 1998.

4. MOHAMED NOUR EL-DIN ABD-ALLA“Application of recent techniques of pushover forevaluating seismic performance of multistorybuildings”, Faculty of Engineering, Cairo UniversityGiza, Egypt September 2007.

5. KasımArmagan KORKMAZ, Fuat DEM_R andMustafa S_VR_ “Earthquake assessment of R/Cstructures with masonry infill walls” SuleymanDemirelUniversity, Civil Engineering Department, Cunur,Isparta, TURKIYE [email protected].(Received: 06.08.2007; Accepted: 03.10.2007

6.IS: 1893 (Part-I) 2002 (2002): Criteria for EarthquakeResistant Design of Structures, Part-I GeneralProvisions and Buildings, Fifth Revision, Bureau ofIndian Standards, New Delhi

7. Kanitkar, R., and Kanitkar, V., “Seismic Performanceof Conventional Multi-storey Buildings with OpenGround Storey for Vehicular Parking”, Indian ConcreteJournal, February 2004.

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