seismic evaluation and retrofit of reinforced concrete

Research ArticleSeismic Evaluation and Retrofit of Reinforced ConcreteBuildings with Masonry Infills Based on Material StrainLimit Approach

Mangeshkumar R Shendkar1 Denise-Penelope N Kontoni 23 Sasankasekhar Mandal1

Pabitra Ranjan Maiti1 and Omid Tavasoli 4

1Department of Civil Engineering Indian Institute of Technology (IIT-BHU) Varanasi 221 005 India2Department of Civil Engineering University of the Peloponnese Patras GR-26334 Greece3School of Science and Technology Hellenic Open University Patras GR-26335 Greece4Department of Civil Engineering Islamic Azad University East Tehran Branch Tehran Iran

Correspondence should be addressed to Denise-Penelope N Kontoni kontoniuopgr

Received 1 February 2021 Revised 12 March 2021 Accepted 24 March 2021 Published 7 April 2021

Academic Editor Nerio Tullini

Copyright copy 2021 Mangeshkumar R Shendkar et al +is is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in anymedium provided the original work isproperly cited

+e seismic evaluation and retrofit of reinforced concrete (RC) structures considering masonry infills is the correct methodologybecause the infill walls are an essential part of RC structures and increase the stiffness and strength of structures in seismicallyactive areas A three-dimensional four-storey building with masonry infills has been analyzed with nonlinear static adaptivepushover analysis by using the SeismoStruct software Two models have been considered in this study the first model is a full RC-infilled frame and the second model is an open ground storey RC-infilled frame +e infill walls have been modeled as a doublestrut nonlinear cyclic model In this study the ldquomaterial strain limit approachrdquo is first time used for the seismic evaluation of RCbuildings with masonry infills +is method is based on the threshold strain limit of concrete and steel to identify the actualdamage scenarios of the structural members of RC structures+e twomodels of the four-storey RC building have been retrofittedwith local and global strengthening techniques (RC-jacketing method and incorporation of infills) as per the requirements of thestructure to evaluate their effect on the response reduction factor (R) because the R-factor is an important design tool that showsthe level of inelasticity in a structure A significant increase in the response reduction factor (R) and structural plan density (SPD)has been observed in the case of the open ground storey RC-infilled frame after the retrofit+us this paper aims to present a mosteffective way for the seismic evaluation and retrofit of any reinforced concrete structure through the material strainlimit approach

1 Introduction

Nowadays there is a need for seismic evaluation and retrofitof the structures due to too many problems like designdeficiency construction deficiency and aging of structuresRetrofitting is defined as the process of modification of anexisting structure like buildings and bridges to make themmore resistant to seismic activity and other natural disastersEarthquake is one of the most dangerous natural disasters tostructures so there is a need for special care mainly in thedesign of structures +e aging of structures mostly causes

the loss of their strength for many reasons like seismicactivity soil failure and failure of structural members likecolumns beams and slabs due to design and constructiondeficiency So for safety purposes there is a need forstrengthening options

Alguhane et al [1] presented the study on the seismicevaluation of an existing 5-storied RC building with differentinfill configurations at Madinah city +ey presented fourmodel systems as bare frame frame with infill from field testframe infilled as per ASCE 41 and frame infilled togetherwith open ground story according to ASCE 41 +e response

HindawiShock and VibrationVolume 2021 Article ID 5536409 15 pageshttpsdoiorg10115520215536409

modification factor (R) for the 5-storey RC building wasevaluated from capacity and demand spectra for all models+e authors concluded that the R-factor increases due to thepresence of infill and it satisfies the requirement of the code(SBC 301) but the bare frame does not satisfy the re-quirement of the response modification factor Chaulagainet al [2] evaluated the response reduction factor (R-factor)of 12 existing irregular reinforced concrete buildings inKathmandu Valley using pushover analysis +ey concludedthat the computed values of the R-factor obtained for dif-ferent bare frame structures were less than the suggestedvalues in the IS 1893 (2002) code Sadrmomtazi et al [3]worked on the seismic evaluation and retrofitting of dam-aged structures in the Sarpole earthquake In that study a 3-storey RC building was evaluated in Iran Initially they havecollected the general information of the sample building andafter that conducted the NDT Ultimately after a detailedstudy they concluded that a lack of monitoring and con-struction mistakes such as reinforcement bending stirrupspacing and covers makes a more vulnerable structure+erefore it is necessary to monitor the building for preciseconstruction to vanish the disaster effect Dolsek and Fajfar[4] worked on the seismic assessment of a four-storey RCframe with masonry infills by using the N2 method +reemodels have been taken for the study purpose as bare framepartially infilled frame and fully infilled frame+e results ofthat study indicate that the infills can completely change thedistribution of damage throughout the structure and it canhave a beneficial effect on the structural response Uva et al[5] worked on the seismic evaluation of an existing RCframed building located in a high seismic risk area inCalabria An experimental test has been carried out on thebuilding to assess the present condition and its qualityNonlinear static pushover analysis has been performed onthe bare frame and infilled frame models +e results of thatstudy recommended that the failure mechanism of theinfilled frame was less as compared with the bare frame dueto the presence of infill walls Cavaleri et al [6] worked onthe influence of column shear failure on the seismic as-sessment of RC-infilled structures +e seismic performanceof the RC structure was evaluated by using concentricequivalent struts for modeling infills and the level of theadditional shear on the columns+rough that paper the useof concentric struts for the infills may overestimate thestructural capacity and the additional shear demand pro-duced by infills just for the base columns Mazza [7] eval-uated a hospital structure against in-plane and out-of-planeseismic collapse of masonry infills In that study the base-isolation as a retrofitting technique was used for improvingthe IP (in-plane) and OOP (out-of-plane) response of infillwalls Mazza [8] worked on dissipative steel exoskeletons(DEX) for the seismic control of RC buildings +e dissi-pative exoskeleton (DEX) appears convenient from ener-getic and functional points of view +ree arrangements ofDEX were applied externally parallel (DEXPa) and per-pendicular (DEXPe) to all faccedilades of the existing buildingand a mixed (DEXMi) solution +e results of that studyindicate that the axial load in the columns whose intensity islarger for DEXPa than DEXPe and DEXMi due to

overturning moments induced by seismic loads and DEXPeis the most attractive solution for the tensile axial loadtransformation to the foundation El-Betar [9] worked onthe seismic vulnerability of two existing RC buildings inEgypt +e two case studies were selected for the seismicevaluation purpose as old and new school buildings +eresults of the study recommended that an old schoolbuilding was a more vulnerable structure under high seismicload

Most of the residential buildings were designed forgravity loading only in a high seismic region so there isalways a need to check the seismic performance of thestructures by using pushover analysis +e pushover analysismay help engineers to take the initiative for rehabilitationwork by identifying the weak elements [10 11]

Arya and Agarwal [12] explained the guidelines onseismic evaluation and the strengthening of existing rein-forced concrete buildings +e preliminary and detailedevaluation process of the existing buildings was explainedclearly As per the report site visit collection of data con-figuration-related checks and strength-related checks arerequired for preliminary evaluation purposes and if all thesechecks are satisfied with structural integrity then there is noneed to go for detailed evaluation In detailed evaluationlinear static or linear dynamic analysis is required to checkthe demand to capacity ratio of structural members If thedemand to capacity ratio is greater than 1 then the structuralmember is considered as a deficient member and the dif-ferent retrofitting strategies are applied (such as RC jack-eting addition of infills shear wall and bracings) tostrengthen the structure

+e failure pattern of a reinforced concrete structure isan important aspect to be assessed Many researchers haveworked on the failure pattern of the RC frames in severalways +e ldquomaterial strain limit approachrdquo is the newlydeveloped and most realistic method to identify the damageof the reinforced concrete structures Based on this ap-proach it will help to get information regarding the actualdamage in the materials of RC structures [13ndash15] Reliabilityanalysis of RC structures is very important because of theconsideration of uncertainties as an important dimension ofperformance-based earthquake engineering which accountsfor uncertainties in modeling and design [16 17]

+e present study attempts to seismically evaluate thereinforced concrete buildings with masonry infills in asystematic approach viz by using the ldquomaterial strain limitapproachrdquo and the retrofit is based on the deficiencies in thebuilding Also we present a comparison between the valuesof seismic design parameters (R-factor ductility andoverstrength factor) obtained from numerical analyses be-fore and after the retrofit of the RC buildings

2 Methodology

21 Adaptive Pushover Analysis In recent years the appli-cation of pushover analysis is generally used to check thenonlinear response of structures It represents a significantalternative solution for nonlinear dynamic analysis ofstructures In the case of a multistoried structure ignoring

2 Shock and Vibration

the effect of higher modes is one of the limitations of suchapproaches Some researchers proposed considering highermode effects depending on adaptive pushover procedureswhich include the increasing variation in the dynamicproperties like time period and frequency [18 19] For thisthe applied load is revised at every incremental actiondepending on the current dynamical properties of thestructure

Antoniou and Pinho [20] used a force-based adaptivepushover analysis in which the lateral load is continuouslyrevised at every single step during the eigenvalue analysis+e SRSS method was used to combine the responses of eachmode In this advanced static analysis method the spectralamplification part is also important for updating the loadvectors According to the literature for the adaptive push-over case one can introduce the record of earthquakeground motion and define the level of damping In thepresent study for spectral amplification we considered theaccelerogram time history of the Chi-Chi earthquake(magnitude 76 location 2378deg N and 12109deg E and re-cording station TCU045) in Taiwan (date 20 September1999) taken from PEER database [21] as shown in Figure 1and its response spectrum is shown in Figure 2 In thepresent study adaptive and conventional pushover analyseshave been used for comparison purposes and finally all theseismic design parameters have been evaluated based onlyon the adaptive pushover analysis due to its more realisticnature as compared with the conventional pushoveranalysis

22 Response Reduction Factor +e R factor is generallyused to minimize elastic response to inelastic responsestructures In other words the response reduction factor (R)is defined as the ratio of elastic strength to inelastic designstrength From the existing literature it is seen that the R-factor is mainly a function of three factors viz the ductilityfactor the overstrength factor and the redundancy factor Itis mathematically expressed as

R Rd times RO times RR (1)

where R is the response reduction factor Rd is the ductilityreduction factor RO is the overstrength factor and RR is theredundancy factor Figure 3 provides an explanation of allthese factors According to the BIS (Bureau of IndianStandards) code provisions it is mathematically representedas follows [23 24]

2R Rd times RO (2)

According to ATC-19 [25] the product of the ductilityreduction factor redundancy and the overstrength factor isthe response reduction factor

221 Ductility Reduction Factor +e ductility reductionfactor (Rd) provides a measure of the global nonlinear re-sponse of a structure It mainly depends on the ductility andthe fundamental time period of any structure +e dis-placement ductility μ is expressed as

μ Δmax

Δy

(3)

where Δmax is the maximum displacement corresponding tothe peak base shear of the pushover curve and Δy is the yielddisplacement calculated by using the reduced stiffnessmethod based on the bilinearization curve (Figure 4) [26]

+e R-μ-Trelationships developed by Newmark andHall[27] were used to evaluate Rd as follows

If time period lt02 seconds Rd 1If 02 secondslt time periodlt 05 seconds Rd 2μ minus 1

1113968

If time periodgt 05 seconds Rd μ

222 Overstrength Factor +e overstrength factor (RO) is ameasure of the reserved strength present in a structure +emain sources of the overstrength factor are (i) materialstrength (ii) load factors and their combination (iii) par-ticipation of nonstructural elements like infill walls and (iv)redundancy It may be expressed as follows

RO Vy

Vd

(4)

where Vy is the ideal yield base shear and Vd is the designbase shear

223 Redundancy Factor +e redundancy factor (RR) isusually defined as the gap between the local yield point to theglobal yield point of a structure Any building should have ahigh degree of redundancy for lateral resistance In thisstudy the redundancy factor is incorporated into theoverstrength factor

Recommended values of the response reduction factor(R) by the BIS (Bureau of Indian Standards) code are shownin Table 1

3 Seismic Evaluation and Retrofitting Procedure

31 General Practice for Seismic Evaluation and RetrofittingGenerally for the seismic evaluation purpose of structures anequivalent static method (linear static method) is used In thismethod the base shear is calculated based on different seismicparameters like zone factor importance factor R-factorspectral acceleration coefficient and seismic weightAfter the calculation of the base shear it is distributed ateach floor as per IS (Indian Standards) code provisionsSubsequently a check is done of the deficient members ofstructures based on different deformations criteria egcheck of the demand (D) to capacity (C) ratio (DC) IfDC gt 1 then the member is called a deficient memberAfter that different retrofitting techniques are used forthe respective deficient members and thus the structureis finally retrofitted

32 A Systematic Approach for Seismic Evaluation andRetrofit In current practice a linear static method is morepopular for the seismic evaluation of structures In this

Shock and Vibration 3

ndash04

ndash03

ndash02

ndash01

0

01

02

03

0 10 20 30 40 50 60

Acc

eler

atio

n (g

)

Time (s)

Figure 1 Acceleration time history of the Chi-Chi earthquake [21]

07

06

05

04

03

02

01

0

Acce

lera

tion

(g)

0 05 1 15 2 25Time (s)

3 35 4 45

Figure 2 Acceleration response spectrum of the Chi-Chi earthquake [22]

VE

Vy

Vd

Base

shea

r

075 Vy

Δy Δmax

Top displacement

2R

Rd

Ro

Elastic strength

Actual strength

Actual capacitycurve

Design strength

Idealized envelope

Figure 3 Interrelation between response reduction factor overstrength factor and ductility reduction factor [23 24]


article a systematic approach ie the nonlinear staticadaptive pushover analysis has been used for the seismicassessment of the RC structure through the ldquomaterial strainlimit approachrdquo +e following steps are used

(1) Calculate the design base shear value based on theseismic weight of the structure as per IS 1893 (Part-1)2016 [28]

(2) Distribute the design base shear value at each floor(3) Perform an adaptive pushover analysis of the structure(4) Based on the adaptive pushover analysis results the

pushover curves are plotted and the seismic pa-rameters of the structure are calculated

(5) Based on the material strain limits approach (ieperformance criteria) the deficient members (ifDCgt 1) present in the structure can be identified

(6) +ereafter different techniques of retrofitting (localand global retrofitting schemes) can be applied to thedeficient members

+e ldquomaterial strain limit approachrdquo is a method for theseismic assessment of the reinforced concrete structures basedon the threshold strain limit of concrete and steel to identify theactual damage state of structural members ie microlevelevaluation +is method gives a more precise and reliable so-lution for the seismic assessment of RC structures In this studythe ldquomaterial strain limit approachrdquo is first time used for theseismic evaluation of the RC structures with masonry infills

4 Model Description

For this study a four-storey three-dimensional building (floorto floor height 3m) symmetrical on plan with 3 bays (each span

4m) in both directions is studied+e building is considered inseismic zone ldquoIVrdquo and designed for gravity and lateral earth-quake load +e building is modeled using the SeismoStructsoftware [22] Models were studied for seismic evaluation andretrofitting of structures with an opening in infills as follows

(1) Full RC-infilled frame in both directions(2) Open ground storey RC-infilled frame in both

directions

Figure 5 shows the building plan while Figure 6 showsthe models of the building Table 2 provides the structuraldetails of the building Tables 3 and 4 show the column andbeam dimensions respectively +e structural detailing ofthe column and beam is shown in Figure 7

41 Inelastic Infill Panel Element +e inelastic infill elementis characterized by four axial struts and two shear springs asshown in Figure 8 where Xoi and Yoi represent the hori-zontal and vertical offsets respectively dm is the diagonalstrut length and hz is the equivalent contact length Fournode panel masonry elements were developed by Crisafulli[29] +is element accounts for separately shear and com-pressive behavior of masonry infill and adequately repre-sents the hysteretic response +e stiffness reduction factorto consider opening effects in the infill in numerical mod-eling is given as follows

Wdo 1 minus 25Ar( 1113857Wd (5)

where Wdo is the width of the diagonal strut with an openingin infill Wd the width of the diagonal strut and Ar is theratio of opening area to face area of infill Equation (5) isvalid for openings in walls ranging from 5 to 40 In thispaper the opening size is considered approximately 20

411 Sample Calculation of Equivalent Parameters of Ma-sonry Infill

For bay length 4m storey height 3m and thicknessof infill (t) 230mm

Table 1 Recommended values of the response reduction factor (R)by IS1893 (Part-1) 2016 [28]

Frame system R valueOrdinary moment resisting frame 3Special moment resisting frame 5

V

Vmax

075Vmax

Tota

l bas

e she

ar

Ultimate load

ΔyTop lateral displacement

Figure 4 Reduced stiffness method [26]


Y

X

12m

12m

4m

Figure 5 Plan of the building

(a) (b)

Figure 6 +e two models of the building (a) full RC-infilled frame (b) open ground storey RC-infilled frame

Table 2 Structural details of the building

Type of structure Special moment resisting framesNumber of storeys 4Seismic zone IVFloor height 3mBay span 4m along the X direction and Y directionInfill wall thickness 230mmComp Strength of masonry 5MPaYoungrsquos modulus of masonry 2750MPaWidth of strut with opening in infill 262mmEquivalent contact length (hz) 2037Horizontal offset (Xo) 562Vertical offset (Yo) 75Type of soil Medium stiff soilColumn size (mm) 300times 450Beam size (mm) 250times 450Slab depth (mm) 150Live load (kNm2) 3Material M-25 grade concrete and Fe-415 reinforcementDamping in structure 5Importance factor 12


Compressive strength of infill (fm) 5MPa andmodulus of elasticity of infill 550times fm 2750MPaInfill panel net length 4ndash045 355mInfill panel net height 3ndash045 255mDiagonal length (dinf ) 437mλh h

(Einf t sin 2empty)(4EcIchinf )

41113968

(dimensionlessparameter)Z (π2λh) times h

hz (z3hinf ) times 100Equivalent contact length (hz) 2037For the evaluation of equivalent contact length ofdouble strut Stafford and Smith (1966) adopted thevalue as Z3 and width of strut is calculated as followsWidth of strut 0175 dinf(λh)minus 04

Width of strut with opening (bw) 62mmArea of strut for infill with opening bw times t

6026000 mm2

Horizontal offset (Xoi) 562Vertical offset (Yoi) 75

5 Results and Discussion

51 Pushover Curves +e utilization of nonlinear staticanalysis came into practice in the 1970s but the importanceof this pushover analysis has been realized primarily in thelast two decades In this study the adaptive pushover and

conventional pushover analysis have been used for thesimulation of different models For comparison purposeswe have conducted the two analyses for different models butthe calculation of several parameters like strength ductilityoverstrength factor and R-factor is evaluated only from theadaptive pushover analysis due to the more realistic seismicanalysis as compared with conventional pushover analysis+e significance of infills which play an important role in thereinforced concrete frame has been quantified

Figure 9 shows the pushover curves of two modelsnamely full RC-infilled frame and open ground storey RC-infilled frame in terms of horizontal seismic coefficientversus drift in As per Figure 9 there is a slight differencein adaptive and conventional pushover curves +e im-portant parameters such as ductility overstrength factorand R-factor have been obtained from the adaptive pushovercurves before the retrofit which are presented in Tables 5and 6+e base shear is lower in the open ground storey RC-infilled frame as compared with the full RC-infilled framedue to the absence of masonry infills at the ground storey

52 Damage Patterns Engineers must be capable ofidentifying the instants at which different performancelimit states (eg structural damage) are reached +is canbe efficiently carried out in the SeismoStruct softwarethrough the definition of performance criteria wherebythe attainment of a given threshold value of material strainis monitored during the analysis of a structure Materialstrains usually constitute the best parameter for the

Table 3 Column dimensions and detailing

Column Size (mm) Main reinforcement Shear reinforcementAll columns of thebuilding 300times 450 4 nos of 16mm diameter at the corner and 2 nos of 16mm on the longer

side8mm dia 100mm c

c

Table 4 Beam dimensions and detailing

Beam Size (mm) Main reinforcement Shear reinforcementAll beams of the building 250times 450 2 nos of 16mm diameter at the top as well as the bottom 8mm dia 100mm cc

(a) (b)

Figure 7 Structural detailing of (a) column detailing and (b) beam detailing


080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in

Capacity curves before retrofit

Full RC-infilled frame adaptivepushover-X and Y direction

Full RC-infilled frame conventionalpushover-X and Y direction

Open ground storey RC-infilled frame adaptivepushover-X and Y direction

Open ground storey RC-infilled frame conventionalpushover-X and Y direction

Figure 9 Pushover curves of different frames before the retrofit

Internal nodeExternal node

dm

XoiYoi

hz

(a)

Deactivate (tension)

Active (compression)

(b)

Figure 8 Inelastic infill panel element [29]

Table 5 Comparison of different parameters for the full RC-infilled frame

Parameters

Before retrofit After retrofit

RemarksFull RC-infilledframe

Full RC-infilledframe



In X-axis In Y-axis In X-axis In Y-axis

Ultimate capacity 705610 kN 706399 kN 788747 kN 807272 kN After retrofitting 1178 increases in X-axisand 1427 increases in the Y-axis

Yield displacement 6048mm 6042mm 6633mm 685mm After retrofitting 967 increases in the X-axis and 1337 increases in the Y-axis

Maximumdisplacement 70mm 70mm 100mm 100mm After retrofitting 4285 increases in X-axis

and Y-axis

Ductility 116 116 151 146 After retrofitting 3017 increases in X-axisand 2586 increases in the Y-axis

Ductility reductionfactor 115 115 142 138 After retrofitting 2347 increases in X-axis

and 2000 increases in Y-axisOverstrengthfactor 1019 1020 1139 1166 After retrofitting 1177 increases in X-axis

and 1431 increases in the Y-axis

Time period 032 s 032 s 031 s 031 s After retrofitting 3125 decreases in X-axisand Y-axis

R-factor 585 586 808 804 After retrofitting 3811 increases in X-axisand 3720 increases in the Y-axis


identification of the performance state of a given structurewhen compared with other existing methods It is possiblein the SeismoStruct program because in this software thedistributed inelasticity (ie realistic phenomena) is givento each structural member so it is easy to identify theactual damage phenomena based on the materials in astructure

To check the damage patterns of the structures theperformance criteria based on material strain used in thepresent numerical simulation are (1) yield strain limit forsteel 00025 (2) crushing strain limit for unconfined con-crete 00035 (3) crushing strain limit for confined concrete0008 and (5) fracture strain limit for steel 006 [13ndash15 30]+e different damage states have been described in detail forthe different models as in Tables 7 and 8

As per Figure 10 the first yielding of reinforcing steeloccurred at base shear of 469447 kN and displacement of35mm +us this frame is able to sustain more load ascompared with open ground storey RC-infilled frames Firstcrushed unconfined concrete ie spalling of cover concreteoccurred at base shear of 652723 kN and displacement of8167mm also the first crushed confined concrete iecrushing of the core portion of concrete occurred at524889 kN and displacement of 15167mm

As per Figure 11 the first yielding of steel occurred atbase shear of 468856 kN and displacement of 35mm +isframe is able to sustain more load as compared with openground storey RC-infilled frames First crushed unconfinedconcrete ie spalling of cover concrete occurred at baseshear of 652916 kN and displacement of 8167mm also first

crushed confined concrete ie crushing of the core portionof concrete occurred at 525425 kN and displacement of15167mm

As per Figure 12 the first yielding of reinforcing steeloccurred at base shear of 143730 kN and displacement of2801mm+is frame sustains less load as compared with thefull RC-infilled frame First crushed unconfined concreteie spalling of cover concrete occurred at base shear of149859 kN and displacement of 4202mm also first crushedconfined concrete ie crushing of the core portion ofconcrete occurred at 115256 kN and displacement of12595mm

As per Figure 13 the first yielding of steel occurred atbase shear of 143411 kN and displacement of 28mm +isframe sustains less load as compared with the full RC-infilledframe First crushed unconfined concrete ie spalling ofcover concrete occurred at base shear of 147610 kN anddisplacement of 56mm also first crushed confined concreteie crushing of the core portion of concrete occurred at115998 kN and displacement of 126mm

53 Retrofit of the Building To check the damage patterns ofdifferent frames the performance criteria based on thematerial strain used in the present numerical simulation are(i) yield strain limit for steel 00025 (ii) crushing strain limitfor unconfined concrete 00035 (iii) crushing strain limitfor confined concrete 0008 and (iv) fracture strain limit forsteel 006 [13ndash15 30] Based on the above values the de-ficient members in the structure are identified by a critical

Table 6 Comparison of different parameters for the open ground storey RC-infilled frame

Parameters


RemarksOpen ground

storey RC-infilledframe

Open groundstorey RC-infilled

frame


frame


frameIn X-axis In Y-axis In X-axis In Y-axis

Ultimate capacity 150598 kN 149858 kN 624119 kN 625054 kNAfter retrofitting 31442

increases in X-axis and 31709increases in the Y-axis

Yielddisplacement 2214mm 2193mm 5462mm 5472mm

After retrofitting 14670increases in the X-axis and

14952 increases in the Y-axis

Maximumdisplacement 42mm 42mm 9333mm 8667mm

After retrofitting 12221increases in X-axis and 10635

increases in the Y-axis

Ductility 189 191 170 158After retrofitting 1005

decreases in X-axis and 1727decreases in the Y-axis

Ductilityreduction factor 167 168 155 147

After retrofitting 718 decreasesin X-axis and 125 decreases in

Y-axis

Overstrengthfactor 217 216 901 902



Time period 048 s 048 s 032 s 032 s After retrofitting 3333decreases in X-axis and Y-axis

R-factor 181 181 698 662After retrofitting 28563



combination of strain limit criteria in X as well as Y di-rections +ere were 8 columns (at ground storey) deficientin the case of full RC-infilled frame while all ground col-umns ie 16 columns were deficient in the case of the openground storey RC-infilled frame Consequently the full RC-infilled frame has been retrofitted with the RC-jacketingmethod size of retrofitted column 450times 600mm ie they

are retrofitted with M30 grade of concrete around theexisting member as the core of a column with the 4 numbersof 20mm diameter of 415-grade steel as detailed in Fig-ure 14 +e retrofitted plan of the full RC-infilled frame isshown in Figure 15

+e open ground storey RC-infilled frame has beenretrofitted with the RC-jacketing method as well as the

Table 7 Material strain level of the open ground storey RC-infilled frame

Material strainlevel

Before retrofit After retrofitOpen ground storey RC-

infilled frame-XOpen ground storey RC-

infilled frame-YOpen ground storey RC-


infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

First yielding ofsteel 2800 143411 2801 143730 2667 381724 2667 381401

First crushing ofunconfinedconcrete

5600 147610 4202 149859 8000 603878 8667 625054

First crushing ofconfined concrete 12600 115998 12595 115256 15333 523776 14667 541695

Table 8 Material strain level of the full RC-infilled frame


Before retrofit After retrofitFull RC-infilled frame-X Full RC-infilled frame-Y Full RC-infilled frame-X Full RC-infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN

0 50 100 150 200 250 300 350 400Displacement in mm

First yield

First crush_unconfinedFirst crush_confined

469447

652723 524889

Figure 10 Damage pattern of full RC-infilled frame in Y direction


incorporation of infill panels at the corners in both direc-tions and also provided the four infill panels at central coreportion so ie 12 infills are provided at ground storeyadopted as the global strengthening method For the open

ground storey case it was adopted local strengthening aswell as global strengthening method because this case ismore vulnerable to lateral loads but in the case of full RC-infilled frame there is a need of only a few members toretrofit by local strengthening ie RC-jacketing method+e retrofitted plan of the open ground storey RC-infilledframe is shown in Figure 16

Figure 15 shows the retrofitted plan of the full RC-infilledframe +ere were eight deficient column members found atthe ground storey based on the material strain limit approach+e four corner columns and four middle columns at theground storey of the building were identified as deficient sothe RC-jacketing method (local strengthening) was used tostrengthen these deficient members of the building

Figure 16 shows the retrofitted plan of the open groundstorey RC-infilled frame +ere were 16 deficient columnmembers found at the ground storey based on the materialstrain limit approach +e RC-jacketing method (localstrengthening) was used to strengthen all the deficientmembers of the building and also the addition of masonryinfills (global strengthening) at the ground storey of thebuilding ie masonry infills were added at the middle coreportion and both directions of each corner as shown inFigure 16

531 Pushover Curves after Retrofit Figure 17 shows thepushover curves of different frames after retrofit in terms ofhorizontal seismic coefficient versus drift in As perFigure 17 there is a slight difference in adaptive and con-ventional pushover curves +e important parameters suchas ductility overstrength factor and R-factor have beenobtained from the adaptive pushover curves after the

010002000300040005000600070008000

Base

shea

r in

kN

50 200 300100 2501500 400350Displacement in mm

525425

652916

468856

First yieldFirst crush_unconfinedFirst crush_confined

Figure 11 Damage pattern of full RC-infilled frame in X direction

50 100 150 200 250 3000Displacement in mm

0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256


Figure 12 Damage pattern of open ground storey RC-infilledframe in Y direction

0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998


Figure 13 Damage pattern of open ground storey RC-infilledframe in X direction

Figure 14 RC jacketed column


retrofit which are presented in Tables 5 and 6 +e majorstudy observed that the capacity of the frames has beenincreased significantly after the retrofit

A comparison of different parameters is presented inTable 5 From Table 5 significant conclusions can be drawnBased on Table 5 the most important parameter the R-factorof the building is increased by averagely (average value in Xand Y direction) 3765 due to the RC jacketing of few groundcolumns In full RC-infilled frames the probability of gettingdeficientmembers is less as comparedwith that of open groundstorey RC-infilled frame because infills are present in theground storey thus it lowers the cost of retrofitting of thebuilding It could be noted that the parameters viz ductilityductility reduction factor overstrength factor and responsereduction factor are slightly increased as compared with theopen ground storey RC-infilled frame after the retrofit

Based on Table 6 the most important parameter theR-factor of the building is significantly increased byaveragely (average value in X and Y direction) 27568due to RC jacketing of ground columns as well as theaddition of infills at the ground storey In the open groundstorey RC-infilled frame the probability of getting defi-cient members is more than that of the full RC-infilledframe because infills were not present in the groundstorey which makes the soft storey building increase thecost of retrofitting the building due to such a vulnerablesoft storey effect In this case the ductility decreases byaveragely 1366 due to the application of both local (RCjacketing of column) and global (addition of infills) ret-rofitting techniques and the other parameters like theoverstrength factor and the response reduction factor aresignificantly increased after the retrofit

4m

12m

12m

RC jacketedcolumn

Y

X

Figure 15 Retrofitted plan of the full RC-infilled frame

4m

12m

12m

RC jacketedcolumn

Y

X

Incorporationof infill

Figure 16 Retrofitted plan of the open ground storey RC-infilled frame


Based on Table 7 after the retrofit of open ground storeyRC-infilled frame the deformations like yielding of steelcrushing of unconfined and confined concrete have oc-curred late as compared with those before the retrofitQuantitatively after the retrofit of the building the baseshear corresponding to the yielding of steel is averagely 265times more as compared with that before the retrofitSimilarly in the same case the base shear corresponding tothe crushing of unconfined concrete is averagely 413 timesmore as compared with that before the retrofit Also in thelast stage the base shear corresponding to the crushing ofconfined concrete is averagely 460 times more as comparedwith that before the retrofit

Based on Table 8 after the retrofit of the full RC-infilledframe the deformations like yielding of steel crushing ofunconfined and confined concrete have occurred late ascompared with those before the retrofit Quantitatively afterthe retrofit of the full RC-infilled frame the base shearcorresponding to the yielding of steel is averagely 106 timesmore as compared with that before the retrofit Similarly inthe same case the base shear corresponding to the crushingof unconfined concrete is averagely 114 times more ascompared with that before the retrofit Also in the last stagethe base shear corresponding to the crushing of confinedconcrete is averagely 120 times more as compared with thatbefore the retrofit

54 Structural Plan Density Structural plan density is animportant structural parameter that helps to make anearthquake-resistant structure +e area of vertical membersof a building has been reduced significantly from about50ndash60 of the plinth area in historic masonry buildings to a

small 2ndash4 in modern RC frame buildings +e structuralplan density (SPD) is the ratio of the area of the footprint ofvertical elements (at ground) resisting the lateral load to theplinth area of the building SPD is low for gravity load designof buildings and increases for gravity plus lateral load designof buildings (to about 4 or more) [31] +e area of verticalmembers is necessary to be larger in order to make thebuildings more earthquake resistant In the present studytwo models are as follows (a) full RC-infilled frame and (b)open ground storey RC-infilled frame We have evaluatedthe SPD in for these two models before and after theretrofit and also demonstrated a graph between the averageresponse reduction factor and structural plan density in asshown in Figures 18 and 19

541 Calculation of Structural Plan Density (SPD)

(1) Full RC-infilled frame before the retrofit is as followsTotal area of footprint of vertical elements columnfootprint + infill footprint 216 + 2001 2217m2

Total plinth area 123times124515313m2

SPD (221715313) times 100 1447(2) Open ground storey RC-infilled frame before the

retrofit is as followsTotal area of footprint of vertical elements columnfootprint + infill footprint 216 + 0 216m2


SPD (21615313) times 100 141(3) Full RC-infilled frame after the retrofit is as follows

Total area of footprint of vertical elements columnfootprint + infill footprint 324 + 1959 2283m2


SPD (228315313) times 100 1490(4) Open ground storey RC-infilled frame after the

retrofit is as followsTotal area of footprint of vertical elements columnfootprint + infill footprint 432 + 9571389m2


SPD (138915313) times 100 907

Figure 18 shows the graph of average R-factor versusstructural plan density () for the full RC-infilled frame Asper Figure 18 after the retrofit of the full RC-infilled framethe value of average R-factor and structural plan densityincreases by 3777 and 297 respectively Also we canobserve that as the structural plan density increases and thevalue of the response reduction factor also increases

Figure 19 shows the graph of average R-factor versusstructural plan density () for the open ground storey RC-infilled frame As per Figure 19 after the retrofit of the openground storey RC-infilled frame the value of average R-factor and structural plan density increases by 375 times and643 times respectively Also we can observe as the struc-tural plan density increases and the value of the responsereduction factor also increases

080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in


Full RC-infilled frame adaptive pushover-Y direction

Full RC-infilled frame adaptive pushover-X direction

Full RC-infilled frame conventional pushover-X direction

Full RC-infilled frame conventional pushover-Y direction



Figure 17 Pushover curves of different frames after retrofit


6 Conclusions

According to analytical results the following conclusionscan be drawn from the present study +e base shear valuesof the retrofitted building are slightly larger as comparedwith those before retrofit in the case of the full RC-infilledframe Also in the case of the open ground storey RC-infilled frame the values of the base shear increase signif-icantly after the application of local and global retrofittingtechniques In the case of the open ground storey RC-infilledframe the ductility and ductility reduction factors areslightly decreased after the retrofit due to the application ofboth local and global retrofitting techniques +e over-strength factors are significantly influenced in the retrofittedbuilding by the application of RC jacketed columns as well asthe incorporation of infills Also as a result of it the responsereduction factors of the retrofitted buildings are significantlyhigher as compared with those before the retrofit Beforeretrofitting the computed values of R for the full RC-infilledbuilding are slightly more than the value (ie 5 for specialmoment resisting frames SMRF) recommended by the IS1893 (Part I) 2016 code but in the case of the open groundstorey RC-infilled building the calculated R values aresignificantly less as compared with the values given by theBIS code due to the soft storey effect After retrofitting thecomputed values of R for the full RC-infilled building aresignificantly more than the value (ie 5 for SMRF) rec-ommended by the IS 1893 (Part I) 2016 code due to theapplication of local retrofitting technique However in thecase of open ground storey RC-infilled building the cal-culated R values are more than the values given by the BIS

(Bureau of Indian Standards) code due to the application ofboth local and global retrofitting techniques As the struc-tural plan density increases the value of the response re-duction factor increases due to the higher structuralfootprint area Generally in current construction practicesof open ground storey RC buildings the structural plandensity should be greater as possible to make a strongearthquake-resistant structure Based on the present studythe material strain limit approach is the most effective way toidentify the realistic damage state of reinforced concretestructures

Data Availability

+e data used to support the findings of this study are in-cluded within the article and there are no restrictions ondata access

Conflicts of Interest

+e authors declare that they have no conflicts of interestregarding the publication of this paper

References

[1] T M Alguhane A H Khalil M N Fayed and A M IsmailldquoSeismic assessment of old existing RC buildings with ma-sonry infill in Madinah as per ASCErdquo International Journal ofComputer and Systems Engineering vol 9 no 1 pp 52ndash632015

[2] H Chaulagain H Rodrigues E Spacone R GuragainR Mallik and H Varum ldquoResponse reduction factor of ir-regular RC buildings in Kathmandu valleyrdquo EarthquakeEngineering and Engineering Vibration vol 13 no 3pp 455ndash470 2014

[3] A Sadrmomtazi H Nsersaeed and H Vakhshoor ldquoSeismicperformance evaluation and retrofitting scheme of damagedstructures in sarpol earthquakerdquo in Proceedings of the 4thInternational Congress on Engineering Technology amp AppliedSciences New Zealand Auckland June 2019

[4] M Dolsek and P Fajfar ldquo+e effect of masonry infills on theseismic response of four storey reinforced concrete frame-adeterministic assessmentrdquo Engineering Structures vol 30no 7 pp 1991ndash2001 2008

[5] G Uva F Porco and A Fiore ldquoAppraisal of masonry infillwalls effect in the seismic response of RC framed buildings acase studyrdquo Engineering Structures vol 34 pp 514ndash526 2012

[6] L Cavaleri F Di Trapani P G Asteris and V SarhosisldquoInfluence of column shear failure on pushover based as-sessment of masonry infilled reinforced concrete framedstructures a case studyrdquo Soil Dynamics and EarthquakeEngineering vol 100 pp 98ndash112 2017

[7] F Mazza ldquoBase-isolation of a hospital pavilion against in-plane-out-of-plane seismic collapse of masonry infillsrdquo En-gineering Structures vol 228 Article ID 111504 2021

[8] F Mazza ldquoDissipative steel exoskeletons for the seismiccontrol of reinforced concrete framed buildingsrdquo StructuralControl and Health Monitoring vol 28 no 3 p e2683 2021

[9] S A El-Betar ldquoSeismic vulnerability evaluation of existingRC buildingsrdquo HBRC Journal vol 14 no 2 pp 189ndash1972018

0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in

Before retrofit(1447 585)

After retrofit(149 806)

Full RC-infilled frame

Figure 18 Graph of average R-factor versus structural plan density(SPD)

012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in



Open ground storey RC-infilled frame



[10] R Suwondo and S Alama ldquoSeismic assessment of RCbuilding designed by local practicerdquo IOP Conference SeriesEarth and Environmental Science vol 426 pp 1ndash8 2020

[11] M Rahman and A U M Shajib ldquoSeismic vulnerability as-sessment of RC structures a reviewrdquo International Journal ofScience amp Emerging Technologies vol 4 no 4 pp 171ndash1772012

[12] A S Arya and A Agarwal Seismic Evaluation andStrengthening of Existing Reinforced Concrete Buildings-Guidelines National Disaster Management Division Ministryof Home Affairs North Block New Delhi India 2012

[13] M Shendkar S Mandal R Pradeep Kumar and P R MaitildquoResponse reduction factor of RC-infilled frames by usingdifferent methodsrdquo Indian Concrete Institute (ICI) Journalpp 14ndash23 2020

[14] S Mandal and M R Shendkar ldquoEvaluation of response re-duction factor of RC-infilled framesrdquo in Proceedings of the17thWorld Conference on Earthquake Engineering (17WCEE)pp 1ndash12 Sendai Japan September 2020

[15] M R Shendkar S Mandal and R Pradeep Kumar ldquoEffect oflintel beam on response reduction factor of RC-infilledframesrdquo Current Science vol 118 no 7 pp 1077ndash1086 2020

[16] M Grubisic J Ivosevic and A Grubisic ldquoReliability analysisof reinforced concrete frame by finite element method withimplicit limit state functionsrdquo Buildings vol 9 no 5 pp 1ndash222019

[17] A Rezaei Rad and M Banazadeh ldquoProbabilistic risk-basedperformance evaluation of seismically base-isolated steelstructures subjected to far-field earthquakesrdquo Buildings vol 8pp 1ndash22 2018

[18] E Kalkan and S K Kunnath ldquoAdaptive modal combinationprocedure for nonlinear static analysis of building structuresrdquoJournal of Structural Engineering vol 132 no 11 pp 1721ndash1731 2006

[19] B Gupta and S K Kunnath ldquoAdaptive spectra-basedpushover procedure for seismic evaluation of structuresrdquoEarthquake Spectra vol 16 no 2 pp 367ndash391 2000

[20] S Antoniou and R Pinho ldquoAdvantages and limitations ofadaptive and non-adaptive force-based pushover proceduresrdquoJournal of Earthquake Engineering vol 8 no 4 pp 497ndash5222004

[21] Pacific Earthquake Engineering Research Center (PEER)PEER Strong Ground Motion Databases Pacific EarthquakeEngineering Research Center University of CaliforniaBerkeley CA USA 2020 httpspeerberkeleyedupeer-strong-ground-motion-databases

[22] SeismoStruct A Computer Program for Static and DynamicNonlinear Analysis of Framed Structures Seismosoft LtdPavia Italy 2020 httpsseismosoftcom

[23] H Chaulagain ldquoAssessment of response reduction factor ofRC buildings in Kathmandu Valley using nonlinear pushoveranalysisrdquo MEng thesis Purbanchal University BiratnagarNepal 2010

[24] M R Shendkar D-P N Kontoni S Mandal P R Maiti andD Gautam ldquoEffect of lintel beam on seismic response ofreinforced concrete buildings with semi-interlocked andunreinforced brick masonry infillsrdquo Infrastructures vol 6no 1 pp 1ndash18 2021

[25] ATC-19 Structural Response Modification Factors ATC-19Report Applied Technology Council (ATC) Redwood CityCA USA 1995

[26] R Park ldquoDuctility evaluation from laboratory and analyticaltestingrdquo in Proceedings of the 9th World Conference on

Earthquake Engineering vol 8 pp 605ndash616 Tokyo JapanAugust 1988

[27] N M Newmark and W J Hall Earthquake Spectra andDesign Earthquake Engineering Research Institute BerkeleyCA USA 1982

[28] IS 1893 Criteria for Earthquake Resistant Design of Structures-Part 1 General Provisions and Buildings Bureau of IndianStandards New Delhi India 2016

[29] F J Crisafulli Seismic behaviour of reinforced concretestructures with masonry infills PhD thesis University ofCanterbury Christchurch New Zealand 1997

[30] P T Aswin ldquoSeismic evaluation of four story reinforcedconcrete structure by non-linear static pushover analysisrdquoBachelor of Technology thesis National Institute of Tech-nology Rourkela Odisha 2013

[31] A R Vijayanarayanan R Goswami and C V R MurtySpecial Class of Open Ground Storey RC Buildings Built inIndia UNSAFE During Earthquakes Indian Institute ofTechnology Madras Chennai Tamil Nadu 2012


modification factor (R) for the 5-storey RC building wasevaluated from capacity and demand spectra for all models+e authors concluded that the R-factor increases due to thepresence of infill and it satisfies the requirement of the code(SBC 301) but the bare frame does not satisfy the re-quirement of the response modification factor Chaulagainet al [2] evaluated the response reduction factor (R-factor)of 12 existing irregular reinforced concrete buildings inKathmandu Valley using pushover analysis +ey concludedthat the computed values of the R-factor obtained for dif-ferent bare frame structures were less than the suggestedvalues in the IS 1893 (2002) code Sadrmomtazi et al [3]worked on the seismic evaluation and retrofitting of dam-aged structures in the Sarpole earthquake In that study a 3-storey RC building was evaluated in Iran Initially they havecollected the general information of the sample building andafter that conducted the NDT Ultimately after a detailedstudy they concluded that a lack of monitoring and con-struction mistakes such as reinforcement bending stirrupspacing and covers makes a more vulnerable structure+erefore it is necessary to monitor the building for preciseconstruction to vanish the disaster effect Dolsek and Fajfar[4] worked on the seismic assessment of a four-storey RCframe with masonry infills by using the N2 method +reemodels have been taken for the study purpose as bare framepartially infilled frame and fully infilled frame+e results ofthat study indicate that the infills can completely change thedistribution of damage throughout the structure and it canhave a beneficial effect on the structural response Uva et al[5] worked on the seismic evaluation of an existing RCframed building located in a high seismic risk area inCalabria An experimental test has been carried out on thebuilding to assess the present condition and its qualityNonlinear static pushover analysis has been performed onthe bare frame and infilled frame models +e results of thatstudy recommended that the failure mechanism of theinfilled frame was less as compared with the bare frame dueto the presence of infill walls Cavaleri et al [6] worked onthe influence of column shear failure on the seismic as-sessment of RC-infilled structures +e seismic performanceof the RC structure was evaluated by using concentricequivalent struts for modeling infills and the level of theadditional shear on the columns+rough that paper the useof concentric struts for the infills may overestimate thestructural capacity and the additional shear demand pro-duced by infills just for the base columns Mazza [7] eval-uated a hospital structure against in-plane and out-of-planeseismic collapse of masonry infills In that study the base-isolation as a retrofitting technique was used for improvingthe IP (in-plane) and OOP (out-of-plane) response of infillwalls Mazza [8] worked on dissipative steel exoskeletons(DEX) for the seismic control of RC buildings +e dissi-pative exoskeleton (DEX) appears convenient from ener-getic and functional points of view +ree arrangements ofDEX were applied externally parallel (DEXPa) and per-pendicular (DEXPe) to all faccedilades of the existing buildingand a mixed (DEXMi) solution +e results of that studyindicate that the axial load in the columns whose intensity islarger for DEXPa than DEXPe and DEXMi due to

overturning moments induced by seismic loads and DEXPeis the most attractive solution for the tensile axial loadtransformation to the foundation El-Betar [9] worked onthe seismic vulnerability of two existing RC buildings inEgypt +e two case studies were selected for the seismicevaluation purpose as old and new school buildings +eresults of the study recommended that an old schoolbuilding was a more vulnerable structure under high seismicload

Most of the residential buildings were designed forgravity loading only in a high seismic region so there isalways a need to check the seismic performance of thestructures by using pushover analysis +e pushover analysismay help engineers to take the initiative for rehabilitationwork by identifying the weak elements [10 11]

Arya and Agarwal [12] explained the guidelines onseismic evaluation and the strengthening of existing rein-forced concrete buildings +e preliminary and detailedevaluation process of the existing buildings was explainedclearly As per the report site visit collection of data con-figuration-related checks and strength-related checks arerequired for preliminary evaluation purposes and if all thesechecks are satisfied with structural integrity then there is noneed to go for detailed evaluation In detailed evaluationlinear static or linear dynamic analysis is required to checkthe demand to capacity ratio of structural members If thedemand to capacity ratio is greater than 1 then the structuralmember is considered as a deficient member and the dif-ferent retrofitting strategies are applied (such as RC jack-eting addition of infills shear wall and bracings) tostrengthen the structure

+e failure pattern of a reinforced concrete structure isan important aspect to be assessed Many researchers haveworked on the failure pattern of the RC frames in severalways +e ldquomaterial strain limit approachrdquo is the newlydeveloped and most realistic method to identify the damageof the reinforced concrete structures Based on this ap-proach it will help to get information regarding the actualdamage in the materials of RC structures [13ndash15] Reliabilityanalysis of RC structures is very important because of theconsideration of uncertainties as an important dimension ofperformance-based earthquake engineering which accountsfor uncertainties in modeling and design [16 17]

+e present study attempts to seismically evaluate thereinforced concrete buildings with masonry infills in asystematic approach viz by using the ldquomaterial strain limitapproachrdquo and the retrofit is based on the deficiencies in thebuilding Also we present a comparison between the valuesof seismic design parameters (R-factor ductility andoverstrength factor) obtained from numerical analyses be-fore and after the retrofit of the RC buildings

2 Methodology

21 Adaptive Pushover Analysis In recent years the appli-cation of pushover analysis is generally used to check thenonlinear response of structures It represents a significantalternative solution for nonlinear dynamic analysis ofstructures In the case of a multistoried structure ignoring







2R Rd times RO (2)



μ Δmax

Δy

(3)




1113968



RO Vy

Vd

(4)








ndash04

ndash03

ndash02

ndash01

0

01

02

03

0 10 20 30 40 50 60

Acc

eler

atio

n (g

)

Time (s)


07

06

05

04

03

02

01

0

Acce

lera

tion

(g)

0 05 1 15 2 25Time (s)

3 35 4 45


VE

Vy

Vd

Base

shea

r

075 Vy

Δy Δmax

Top displacement

2R

Rd

Ro

Elastic strength

Actual strength


Design strength

Idealized envelope










4 Model Description




directions



Wdo 1 minus 25Ar( 1113857Wd (5)






V

Vmax

075Vmax

Tota

l bas

e she

ar

Ultimate load




Y

X

12m

12m

4m


(a) (b)







41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in



































2R Rd times RO (2)



μ Δmax

Δy

(3)




1113968



RO Vy

Vd

(4)








ndash04

ndash03

ndash02

ndash01

0

01

02

03

0 10 20 30 40 50 60

Acc

eler

atio

n (g

)

Time (s)


07

06

05

04

03

02

01

0

Acce

lera

tion

(g)

0 05 1 15 2 25Time (s)

3 35 4 45


VE

Vy

Vd

Base

shea

r

075 Vy

Δy Δmax

Top displacement

2R

Rd

Ro

Elastic strength

Actual strength


Design strength

Idealized envelope










4 Model Description




directions



Wdo 1 minus 25Ar( 1113857Wd (5)






V

Vmax

075Vmax

Tota

l bas

e she

ar

Ultimate load




Y

X

12m

12m

4m


(a) (b)







41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in






























ndash04

ndash03

ndash02

ndash01

0

01

02

03

0 10 20 30 40 50 60

Acc

eler

atio

n (g

)

Time (s)


07

06

05

04

03

02

01

0

Acce

lera

tion

(g)

0 05 1 15 2 25Time (s)

3 35 4 45


VE

Vy

Vd

Base

shea

r

075 Vy

Δy Δmax

Top displacement

2R

Rd

Ro

Elastic strength

Actual strength


Design strength

Idealized envelope










4 Model Description




directions



Wdo 1 minus 25Ar( 1113857Wd (5)






V

Vmax

075Vmax

Tota

l bas

e she

ar

Ultimate load




Y

X

12m

12m

4m


(a) (b)







41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in





































4 Model Description




directions



Wdo 1 minus 25Ar( 1113857Wd (5)






V

Vmax

075Vmax

Tota

l bas

e she

ar

Ultimate load




Y

X

12m

12m

4m


(a) (b)







41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in






























Y

X

12m

12m

4m


(a) (b)







41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in
































41113968




6026000 mm2









side8mm dia 100mm c

c



(a) (b)



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in






























080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250 300 350Drift in








dm

XoiYoi

hz

(a)



(b)



Parameters










and Y-axis

















Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in







































Parameters


RemarksOpen ground



frame


frame















Y-axis

















infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in







































infilled frame-Y

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



5600 147610 4202 149859 8000 603878 8667 625054





Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)

Displacement(mm)

Baseshear(kN)



8167 652916 8167 652723 8333 715972 9167 773815


8000

7000

6000

5000

4000

3000

2000

1000

0

Base

shea

r in

kN


First yield


469447

652723 524889








010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in



































010002000300040005000600070008000

Base

shea

r in

kN


525425

652916

468856




0200400600800

1000120014001600

Base

shea

r in

kN

143730

149859

115256



0

200

400

600

800

1000

1200

1400

1600

Base

shea

r in

kN


143411

147610

115998








4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in

































4m

12m

12m

RC jacketedcolumn

Y

X


4m

12m

12m

RC jacketedcolumn

Y

X




















SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in














































SPD (138915313) times 100 907



080

070

060

050

040

030

020

010

000

Hor

izon

tal s

eism

ic co

effic

ient

(Ah)

000 050 100 150 200 250Drift in










6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in






























6 Conclusions



Data Availability




References










0123456789

Aver

age R

-fact

or

145 148 149 15146 147144SPD in





012345678

Aver

age R

-fact

or

1 74 80 6 953 102SPD in






























seismic evaluation and retrofit of reinforced concrete

Documents