Seismic Rehabilitation of Concrete Buildings byyg y Converting …2... · 2012-04-27 · ¾Often by filling bay of existing frame, encapsulating its beams & columns. ¾“Collector

SERIES workshopSERIES workshopRole of research infrastructures in seismic rehabilitationRole of research infrastructures in seismic rehabilitationRole of research infrastructures in seismic rehabilitationRole of research infrastructures in seismic rehabilitationIstanbul, 8Istanbul, 8--9 February 20129 February 2012

Seismic Rehabilitation of Concrete Buildings Seismic Rehabilitation of Concrete Buildings by Converting Frame Bays into RC Wallsby Converting Frame Bays into RC Wallsy g yy g y

Michael N. Fardis, Antonis Michael N. Fardis, Antonis SchetakisSchetakis, Elias , Elias StrepeliasStrepelias,, ,, ppUniversity of Patras, GreeceUniversity of Patras, Greece

Strategies for seismic retrofitStrategies for seismic retrofitStrategies for seismic retrofitStrategies for seismic retrofitBaseShear

displacement demand of retrofitted structure

BaseShear

displacement demand of retrofitted structureShear

displacement capacity of existing

t

retrofitted structure

Shear

displacement capacity of existing

t


displacement demand

components

existing displacement demand

components

existingIncrease member deformation capacity

Roof Displacement

displacement demand of existing structure

existing structure

Roof Displacement

displacement demand of existing structure

existing structure

Base displacementBase displacement

deformation capacity (eg, w/FRPs)

Roof DisplacementRoof DisplacementSheardisplacement demand


Sheardisplacement demand


Increase building global stiffness to reduce member

deformation demandexisting structureexisting structure

deformation demand

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 2

Roof DisplacementRoof Displacement

Addition of new concrete wallsAddition of new concrete wallsAddition of new concrete wallsAddition of new concrete wallsMost effective for the reduction of deformation demands in the rest of the structure & avoidance of member strengtheningrest of the structure & avoidance of member strengthening.Often by filling bay of existing frame, encapsulating its beams & columns.“Collector elements” may need to be provided for the transfer of inertia forces from floors to the new wall.


Added walls


Most serious problem of added walls: FoundationMost serious problem of added walls: Foundation(transfer of large M with low N, w/o large uplift & base rotation that (transfer of large M with low N, w/o large uplift & base rotation that

k th l f th ll)k th l f th ll)may weaken the role of the wall)may weaken the role of the wall)

Possible solutions:Large & heavy

footing, encapsulating those of neighbouringthose of neighbouring vertical elements.

Connection to other footings via strong & stiff tie-beams.

Mi il tiMicropiles or tie-downs to the soil.

Uplift of footing of new walls should be modelled in nonlinear analysis


analysis

Example of building with 2 strong walls added in the Example of building with 2 strong walls added in the t di tit di titransverse directiontransverse direction


Footings of strong walls to avoid upliftFootings of strong walls to avoid upliftFootings of strong walls to avoid upliftFootings of strong walls to avoid uplift


X ti f ll / d t il fX-section of new wall w/ detail of boundary element encapsulating the

edge of an existing cross walledge of an existing cross-wall.Note large thickness of new wall


Desirable & most economic solution for the new wallDesirable & most economic solution for the new wallDesirable & most economic solution for the new wallDesirable & most economic solution for the new wall

The flange width of the new wall is equal to the minimum width of beams or columns in the existing frame

Objective: fully monolithic behaviour of the new wall with the beams and the columns of the existing frame


Connection of new “web” to existing Connection of new “web” to existing frame for monolithic behaviourframe for monolithic behaviourframe for monolithic behaviourframe for monolithic behaviour

Dowels along the perimeter, at the wall centreline, transfer the web shear

1) Orthodox solution: Direct connection of web bars to frame via overlapping with starter bars

2) Indirect connection of web bars to the frame – dowels double as anchorageDowel depth: 8Φ in frame length in wallpp g

anchored in the frame + dowelsDowel depth: 8Φ in frame or wall

Dowel depth: 8Φ in frame, length in wall = lapping of web bars (but max distance between spliced bars violated)

or


Design shear for dimensioning the dowelsDesign shear for dimensioning the dowelsDesign shear for dimensioning the dowelsDesign shear for dimensioning the dowels

Calculate max moment of wall at the base, maxMw

1. either from the “overturning” moment of its footing, Μ0=0.5BN, the footing height and the wall “shear span” Ls=M/V ~Hw/2:

M Μ /(1+h/L )Mwo= Μ0/(1+h/Ls)2. or from the moment capacity at the base, MRwd, for the new web

reinforcement and the reinforcement of the 2 existing columns. e o ce e t a d t e e o ce e t o t e e st g co u sIf Mwo< MRwd → maxMw=Mwo, no plastic hinge develops at the base. Design shear at the wall base: Vd=maxMw/Ls.If Mwo> MRwd → maxMw=MRwd, a plastic hinge forms at the base. The design shear at the base includes the shear magnification factor for higher modes (Keinzel): Vd=√[1+0 1(qS (T )/S (T1))2] maxM /Lhigher modes (Keinzel): Vd √[1+0.1(qSe(Tc)/Se(T1))2] maxMw/Ls

• Se(T): elastic spectral value, T1: building fundamental period, • Tc: T at upper limit of the spectrum constant-acceleration range,


c pp p g ,• q: calculated from yield & ultimate wall chord rotations: q ~ θu/θy.

Dimensioning of dowels in shearDimensioning of dowels in shearDimensioning of dowels in shearDimensioning of dowels in shear

Shear resistance of one dowel (design value)( g )1. working as dowel only (solution 1)

ss

maxmaxmax,0 6.1)(

ssffA

ssFsF ydcds=≈ s: slippage, smax ~ 0.1db

2. transferring the tension resistance of web bars (diameter dbw) to the existing frame (solution 2) through tensile stress σs=fyd(dbw/db)2

4

max,0

2

max,0max 11 ⎟⎟⎠

⎞⎜⎜⎝

⎛−=⎟

⎟⎠

⎞⎜⎜⎝

⎛−=

d

bw

yd

sdd

Ff

FFσ

If slippage is large the design shear resistance of the two existing

⎠⎝⎠⎝ dydf


If slippage is large, the design shear resistance of the two existing columns is activated (and added to the total capacity of the dowels)

NonlinearNonlinear modellingmodelling of footing upliftof footing upliftNonlinear Nonlinear modellingmodelling of footing upliftof footing uplift

nonlinear springs connecting the soil to the foundation


Nonlinear spring constitutive lawNonlinear spring constitutive lawNonlinear spring constitutive lawNonlinear spring constitutive law

End moving downwards (δ2>0) End moving upwards (δ1>0)

2d θ ⎛ ⎞

50

100

FB⎛ ⎞⎜ ⎟⎛ ⎞0

22 0

2 2KdF FBd B M

θδ

⎛ ⎞= −⎜ ⎟

⎝ ⎠

50

0 0 01

0

ln 22 2

B M FBFB MM

θδ⎜ ⎟⎛ ⎞⎜ ⎟= + −⎜ ⎟⎜ ⎟⎝ ⎠−⎜ ⎟⎝ ⎠2

⎛ ⎞

-100

-50

F(kN

) 0M⎝ ⎠2

002

22

FBMKdF

FBd Bθ

δ

⎛ ⎞−⎜ ⎟

⎝ ⎠=02 1 ln 2B FBθδ

⎛ ⎞⎛ ⎞= − −⎜ ⎟⎜ ⎟⎜ ⎟

02

2 2KdF FBd B M

θδ

⎛ ⎞= −⎜ ⎟

⎝ ⎠200

-150

21

0

FBd BM

δ202 M⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠⎝ ⎠

02

2 2KdF FBd B M

θδ

⎛ ⎞= −⎜ ⎟

⎝ ⎠2

2 0d B Mδ ⎜ ⎟⎝ ⎠

-0 01 -0 008 -0 006 -0 004 -0 002 0 0 002 0 004 0 006 0 008 0 01-250

-200 22 0d B Mδ ⎜ ⎟

⎝ ⎠θ0=Μ0/Κθ00 0.25Μ ≈ ΒΝ


0.01 0.008 0.006 0.004 0.002 0 0.002 0.004 0.006 0.008 0.01Μετατόπιση (m)Displacement (m)

Application to prototype building of 4 frames, converting Application to prototype building of 4 frames, converting the central bay of exterior frames into walls ( SERFIN)the central bay of exterior frames into walls ( SERFIN)the central bay of exterior frames into walls (~SERFIN)the central bay of exterior frames into walls (~SERFIN)


Nonlinear static analysis with fixed or uplifting footingsNonlinear static analysis with fixed or uplifting footingsNonlinear static analysis with fixed or uplifting footingsNonlinear static analysis with fixed or uplifting footingsEnd moving

upwardsWall fixed upwards

Wall uplifting

Μ-θ diagram of wall at the base

End moving downwards


End moving downwards

Nonlinear static analysis with fixed or uplifting footings (Nonlinear static analysis with fixed or uplifting footings (1.51.5xx1.51.5xx0.80.8mmnder col mnsnder col mns 1 51 5 44 00 0 80 8mm nder allsnder alls / or /o/ or /o 0 250 25 0 60 6m tiem tie beam)beam)under columnsunder columns, 1.5, 1.5x4x4..0x0x0.80.8mm under wallsunder walls,, w/ or w/o w/ or w/o 0.250.25xx0.60.6m tiem tie--beam)beam)

Green circle: “Damage :imitation” per EC8-3Yellow circle: “Significant damage” per ΕC8-3

2500

Yellow circle: Significant damage per ΕC8 3Red circle: “Near Collapse” in bending per EC8-3Purple square: “Near Collapse” in shear per EC8-3

2000Δ-0 22g

Δ-0.28gΔ-0.3gK16-0.32gΔ-0.34g

ΠακτωμένοΜε αποκόλληση-με συνδετήρια δοκάριαΜε αποκόλληση-χωρίς συνδετήρια δοκάρια

FixedUplift – w/ tie-beamsUplift – w/o tie-beams

1500

σης

(kN

)

T1&T2-0.15gT1&T2-0.15g

T1-0.19gΔ-0.22g

K16-0.22g

Κ16-0.22gΔ-0.26g

Δ-0.32g

ear (

kN)

1000

Τέμνουσα

Βάσ

Δ-0.09g Δ-0.09gΔ-0.09gBas

e sh

500

Τ

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 170 0.05 0.1 0.15

0

Μετατόπιση (m)

Displacement (m)

Flexural Flexural damage index for Significant Damage damage index for Significant Damage -- Nonlinear dynamic Nonlinear dynamic l i 0 25l i 0 25 fi dfi d f tif ti (( 1414 dd ))analysis, 0.25g analysis, 0.25g -- fixed fixed footingsfootings ((averageaverage over over 14 14 recordsrecords))

Beams


Vert. elements

FlexuralFlexural damage index for Significant Damage damage index for Significant Damage -- Nonlinear dynamic Nonlinear dynamic l il i liftilifti f tif ti / ti/ ti bb (( // 1414 dd 0 25 )0 25 )analysis, analysis, upliftinguplifting footings footings w/ tiew/ tie--beamsbeams ((av/geav/ge over over 14 14 records, records, 0.25g)0.25g)

Beams

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 19Vert. elements

FlexuralFlexural damage index for Significant Damage damage index for Significant Damage -- Nonlinear dynamic Nonlinear dynamic l il i liftilifti f tif ti titi bb (( // 1414 dd 0 25 )0 25 )analysis, analysis, upliftinguplifting footings, footings, no tieno tie--beamsbeams ((av/geav/ge over over 14 14 records, records, 0.25g)0.25g)

Beams


ShearShear damage index for Significant Damage damage index for Significant Damage -- Nonlinear dynamic Nonlinear dynamic l il i fi dfi d f tif ti (( // 1414 dd 0 25 )0 25 )analysis, analysis, fixedfixed footingsfootings ((av/geav/ge over over 14 14 records, records, 0.25g)0.25g)

Beams


Vert. elements

Shear Shear damage index for Significant Damage damage index for Significant Damage -- Nonlinear dynamic Nonlinear dynamic l il i liftilifti f tif ti / ti/ ti bb (( // 1414 dd 0 25 )0 25 )analysis, analysis, upliftinguplifting footings footings w/ tiew/ tie--beamsbeams ((av/geav/ge over over 14 14 records, records, 0.25g)0.25g)

Beams


ShearShear damage index for Significant Damage, nonlinear dynamic analysis,damage index for Significant Damage, nonlinear dynamic analysis,liftilifti f tif ti titi bb (( // 1414 dd 0 25 )0 25 )upliftinguplifting footings, footings, no tieno tie--beamsbeams ((av/geav/ge over over 14 14 records, records, 0.25g)0.25g)

Beams


Vert. elements

Conclusions from analysisConclusions from analysiswith fixed or uplifting footings with or w/o tiewith fixed or uplifting footings with or w/o tie beamsbeamswith fixed or uplifting footings, with or w/o tiewith fixed or uplifting footings, with or w/o tie--beamsbeams

Rocking of the foundation is beneficial for the walls, but increases the demand on columns, particularly at the base

Damage index values are smaller at the base of the walls without tie-beams

Columns: the maximum damage index values are at the base of the exterior columns in building with tie-beams or at the interior frames in building without tie-beams

Uplifting does not have a major effect on beams.


Seismic assessment and retrofitSeismic assessment and retrofitof 2 real irregular buildingsof 2 real irregular buildingsof 2 real irregular buildingsof 2 real irregular buildings

2-storey buildingith i li d fwith inclined roofs

7-storey buildingith 2 t b k


with 2 set-backs

77--storey buildingstorey building

2nd setback

Foundation planFoundation plan

1st - 5th storey plan


Pushover analysis, asPushover analysis, as--built, built, ±±Χ, Χ, ±±ΥΥ, fixed v uplifting footings, fixed v uplifting footingsFixedUplift

FixedUplift

ar (k

N)

Uplift UpliftB

ase

she

Displacement (m) Displacement (m)Green: Damage Limitation per EC8–3 Yellow: Significant Damage per EC ΕK8–3Red: Near Collapse in bending Purple: Near collapse in shear

p ( ) p ( )

FixedU lift

FixedU lift

ear (

kN)

Uplift Uplift

Bas

e sh

e

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 27Displacement (m) Displacement (m)

Shear & flexural damage index of vertical elements Shear & flexural damage index of vertical elements -- asas--built building for built building for Significant Damage nonlinear dynamic analysis (av/ge over 14 records 0 25gSignificant Damage nonlinear dynamic analysis (av/ge over 14 records 0 25g

FlexureFlexureShearShear

Significant Damage, nonlinear dynamic analysis (av/ge over 14 records 0.25gSignificant Damage, nonlinear dynamic analysis (av/ge over 14 records 0.25g


Seismic retrofit of 7Seismic retrofit of 7 storey building with new wallsstorey building with new wallsSeismic retrofit of 7Seismic retrofit of 7--storey building with new wallsstorey building with new walls


Foundation of new wallsFoundation of new wallsFoundation of new wallsFoundation of new walls


Static eccentricity between C M and C SStatic eccentricity between C M and C S

RetrofittedRetrofittedAsAs--builtbuilt

Static eccentricity between C.M. and C.S.Static eccentricity between C.M. and C.S.

No improvement (the contrary).But, although as-built building is torsionally flexible (torsional


mode T > 1st translational mode T), the retrofitted one is not !

3000Αρχικό Πακτωμένο

2000

Pushover analysis, as built v retrofitted, Pushover analysis, as built v retrofitted, ±±Χ, Χ, ±±Υ, fixed v uplifting footingsΥ, fixed v uplifting footingsPGA at 1st exceedance of Limit State in PGA at 1st exceedance of Limit State in vertical elementsvertical elements

A b ilt fi d

2000

2500

(kN

)

Y-0.26g

Y-0.34g

Y 0 29Y-0.36g

Αρχικό ΠακτωμένοΑρχικό με ΑποκόλλησηΕνισχυμένο ΠακτωμένοΕνισχυμένο με Αποκόλληση

1200

1400

1600

1800(k

N)

Y-0.28gY 0 28

Y-0.14g

Y-0.16g

Y-0.23g

Y-0.31g

Y-0.14g

Y-0.22g

Y-0.3g

Y-0.38gkN

)As-built, fixedAs-built, upliftRetrofitted, fixedRetrofitted, uplift

1000

1500

Τέμνουσα

Βάσης

Y-0.16g

Y-0.23g

Y-0.31g

Y-0.17gY-0.21g

Y-0.24gY-0.28g

Y-0.17gY-0.17g Y-0.21g

Y-0.22gY-0.29g

600

800

1000

1200

Τέμνουσα

Βάσης

Y-0.09g

Y-0.13g

Y-0.2gY-0.2g

Y-0.22gY-0.24g

Y-0.28g

Bas

e sh

ear(

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.450

500


Y-0.09g

-0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 00

200

400


Αρχικό ΠακτωμένοΑρχικό με ΑποκόλλησηΕνισχυμένο ΠακτωμένοΕνισχυμένο με Αποκόλληση

Displacement (m)

As-built, fixedAs-built, upliftRetrofitted, fixedRetrofitted, uplift

Displacement (m)

4000

4500

Y-0.5g4000

4500

Y-0.37g

η ( )Μετατόπιση (m)

Green: Damage Limitation per EC8-3 Yellow: Significant Damage per EC8-3Red: Near Collapse in bending Purple: Near collapse in shear

Displacement (m)

2500

3000

3500

σης

(kN

)

Y-0.19g

Y-0 27gY-0 15g

Y-0.22g

Y-0.26g

Y-0.35g

Y-0.19g

Y-0.36g

g

2500

3000

3500

σης

(kN

)

Y-0.21g

Y-0.26gY-0.31g

Y-0.27gY-0.32g

Y-0.29g

Y-0.35gY-0.39g

ar(k

N)

1000

1500

2000

2500Τέμνουσα

Βάσ

Y-0.07g

Y-0.13gY-0.17g

Y-0.23gY 0.27gY 0.15g

Y-0.16g

1000

1500

2000

2500

Τέμνουσα

Βάσ

Y-0.08g

Y-0.16g

Y-0.18g

g

Y-0.14gY-0.13g

Bas

e sh

ea

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 320 0.05 0.1 0.15 0.2 0.25 0.30

500

1000


Y-0.04g Y-0.04gΑρχικό ΠακτωμένοΑρχικό με ΑποκόλλησηΕνισχυμένο ΠακτωμένοΕνισχυμένο με Αποκόλλ

-0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 00

500

1000


Y-0.04Y-0.05gΑρχικό ΠακτωμένοΑρχικό με ΑποκόλλησηΕνισχυμένο ΠακτωμένοΕνισχυμένο με Αποκόλληση

Displacement (m)Displacement (m)



Pushover analysis, as built v retrofitted, Pushover analysis, as built v retrofitted, ±±Χ, Χ, ±±Υ, fixed v uplifting footingsΥ, fixed v uplifting footingsPGA at 1st exceedance of Limit State in PGA at 1st exceedance of Limit State in beamsbeams

kN)

Bas

e sh

ear(

Displacement (m)


Displacement (m)


Green: Damage Limitation per EC8-3 Yellow: Significant Damage per EC8-3Red: Near Collapse in bending Purple: Near collapse in shear

Displacement (m) p ( )

ar(k

N)

Bas

e sh

ea

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 33Displacement (m)Displacement (m)



Shear & flexural DI of Shear & flexural DI of vertical elementsvertical elements in retrofitted building for Significant in retrofitted building for Significant D li d i l i (D li d i l i (fi dfi d f ti / 14 d 0 25 )f ti / 14 d 0 25 )

ShearShear FlexureFlexureDamage, nonlinear dynamic analysis (Damage, nonlinear dynamic analysis (fixed fixed footings, av/ge over 14 records 0.25g)footings, av/ge over 14 records 0.25g)


Shear & flexural DI of Shear & flexural DI of vertical elementsvertical elements in retrofitted building, Significant Damage, in retrofitted building, Significant Damage, li d i l i (li d i l i ( liftilifti f ti / 14 d 0 25 )f ti / 14 d 0 25 )

ShearShearnonlinear dynamic analysis (nonlinear dynamic analysis (upliftinguplifting footings, av/ge over 14 records 0.25g)footings, av/ge over 14 records 0.25g)

SERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 35Flexure Flexure -- Significant DamageSignificant Damage

Flexural DI in Flexural DI in beamsbeams of retrofitted building for Significant Damage, nonlinear of retrofitted building for Significant Damage, nonlinear d i l i (fi d lif i f i / 14 d 0 2 )d i l i (fi d lif i f i / 14 d 0 2 )dynamic analysis (fixed v uplifting footings, av/ge over 14 records, 0.25g)dynamic analysis (fixed v uplifting footings, av/ge over 14 records, 0.25g)

Fi dFi dSERIES workshop “Role of research infrastructures in seismic rehabilitation”, Istanbul, 8-9 February 2012 36

UpliftUpliftFixedFixed

Conclusions from retrofitted 7Conclusions from retrofitted 7--storey buildingstorey buildingwith fixed or uplifting footingswith fixed or uplifting footings

Fixed footingsNew walls ΤΝ2 ΤΝ3 the elevator wall & some columns of the

with fixed or uplifting footingswith fixed or uplifting footings

New walls ΤΝ2, ΤΝ3, the elevator wall & some columns of the setbacks, don’t meet the flexure limit at Significant Damage LS.New wall ΤΝ1 fails in shear.More damage in beams compared to the as-built building.

Uplifting footingsUplifting footingsAlthough column DI-values increase, “Significant Damage” LS is met, except for few columns at the setbacks.met, except for few columns at the setbacks.Wall DI-values drop < 1.0, except for elevator shaft wall (DI=1.08)Elevator wall & few columns of top floor ~fail to meet shear LS.pFlexural damage in beams increases significantly.


In both cases CFRPs are added to fix the local shortfalls

Cost of retrofitting 7Cost of retrofitting 7 storey building forstorey building for fixedfixed footingsfootingsCost of retrofitting 7Cost of retrofitting 7--storey building for storey building for fixedfixed footingsfootingsCost of added walls:

3

Wall Starter bars plus dowels Dowels doubling as starter barsΤΝ1 13600 € 9300 €

@ 90€ /m3 concrete@ 1€ /kg steelepoxy grouting: @ 9€/Φ20mm dowel

@ 7€/Φ12mm dowel

ΤΝ2 12700 € 8400 €

ΤΝ3 26200 € 19500 €

Total 52500 € 37200 €@ 7€/Φ12mm dowel

Cost of adding CFRPs: @ 40€/m2 CFRP ply

Total 52500 € 37200 €

Cost of adding CFRPs: @ 40€/m CFRP plyVertical element Story DI to be made <1.0 required v provided CFRP Cost €

Column 156 7th - base 1.18 0.08mm → 1 ply 0.12mm 20

Column 157 7th - base 1.29 0.14mm → 2 plies 0.24mm 40

Column 157 7th - top 1.57 0.24mm → 2 plies 0.24mm 40

C l 132 6th b 1 13 0 73 6 li 0 72 260Column 132 6th - base 1.13 0.73mm → 6 plies 0.72mm 260

Elevator wall 1st 1.40 1 ply, 150mm strips / 125mm 1150

Elevator wall 2nd 1.16 1 ply, 100mm strips / 200mm 370


Elevator wall 2 1.16 1 ply, 100mm strips / 200mm 370

Total 1880

Cost of retrofitting 7Cost of retrofitting 7--storey building forstorey building for upliftinguplifting footingsfootingsCost of retrofitting 7Cost of retrofitting 7--storey building for storey building for upliftinguplifting footingsfootingsCost of added walls the same as for fixityCost of adding CFRPs @ 40€ /m2 CFRP plyCost of adding CFRPs, @ 40€ /m2 CFRP ply

Vertical element Story DI to be made <1.0 required v provided CFRP Cost €

Column 163 7th – base 1.71 0.52mm → 4 plies 0.48mm 100 thColumn 163 6th – top 1.06 0.05mm → 1 ply 0.12mm 30

Column 161 6th – base 1.21 0.184mm → 2 plies 0.24mm 50

Column 161 7th – base 1.22 0.19mm → 2 plies 0.24mm 50Column 161 7 base 1.22 0.19mm 2 plies 0.24mm 50

Column 161 7th – top 1.26 0.22mm → 2 plies 0.24mm 50



Column 154 6th – top 1.40 0.33mm → 3 plies 0.36mm 80

C l 157 7th b 1 54 0 24 2 li 0 24 40Column 157 7th – base 1.54 0.24mm → 2 plies 0.24mm 40

Elevator wall 1st 1.15 1 ply, 100mm strips / 200mm 500

Elevator wall 2nd 1.10 1 ply, 100mm strips / 300mm 250


p y, p

Total 1550

22 storey buildingstorey building22--storey buildingstorey building

2nd storey


11stst storey slabstorey slab C M and C SC M and C S11stst--storey slab storey slab –– C.M. and C.S.C.M. and C.S.Torsionally flexible: T i l d T > T f 1stTorsional mode T > T of 1st

translational mode in both directions


5000Πακτωμένο

6000Πακτωμένο

Pushover analysis of asPushover analysis of as--built building, built building, ±±Χ, Χ, ±±ΥΥ, fixed v uplifting footings, fixed v uplifting footingsFixed Fixed

3000

3500

4000

4500

ης (k

N)

Δ-0.28gY-0.35g

Δ-0.49g

Δ-0.63g

Y-0.51gΔ-0.6g

Y-0.71g

ΠακτωμένοΜε αποκόλληση

4000

5000

ης (k

N)

Y 0 26gΔ-0.34g

Δ-0.58gΔ-0.72g

Δ-0.7gY-0.73g

ΠακτωμένοΜε αποκόλληση

kN)

FixedUplift

FixedUplift

1500

2000

2500

3000

Τέμνουσα

Βάσ

η

Δ-0.11g

Y-0.13g

Y-0.16g

Y-0.24gg

Δ-0.1g

Y-0.22gΔ-0.26g

Y-0.36gΔ-0.47g

Y 0.51g

2000

3000

Τέμνουσα

Βάση

Δ-0.1gY-0.12g

Y-0.21gY-0.26g

Y-0.18gY-0.26g

Δ-0.33g

Y-0.51gΔ-0.57g

Y 0.73g

Bas

e sh

ear(

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.090

500

1000

Μ ό ( )

Τ

-0.12 -0.1 -0.08 -0.06 -0.04 -0.02 00

1000

ό ( )

Τ

gΔ-0.09g

Displacement (m) Displacement (m)Μετατόπιση (m)Μετατόπιση (m)Green: Damage Limitation per EC8-3 Yellow: Significant Damage per EC8-3Red: Near Collapse in bending Purple: Near collapse in shear

Displacement (m) Displacement (m)

Fixed FixedU lif

ar(k

N)

Uplift Uplift

Bas

e sh

ea


Shear & flexural damage index in asShear & flexural damage index in as--built building, Significant Damage, built building, Significant Damage, li d i l i (fi d f ti / 14 d 0 25 )li d i l i (fi d f ti / 14 d 0 25 )nonlinear dynamic analysis (fixed footings, av/ge over 14 records 0.25g)nonlinear dynamic analysis (fixed footings, av/ge over 14 records 0.25g)

Flexure Flexure -- Significant DamageSignificant DamageShearShearShearShear

ShearShear


Seismic retrofit with wallsSeismic retrofit with walls C M v C SC M v C SSeismic retrofit with walls Seismic retrofit with walls -- C.M. v C.S.C.M. v C.S.

Only @ ground storey

Remains torsionally flexible(torsional mode T > 1st translational


(mode T in one direction)

Pushover analysis of asPushover analysis of as--built building built building ±±Χ, Χ, ±±ΥΥ, fixed v uplifting footings, , fixed v uplifting footings, PGA at 1PGA at 1stst exceedanceexceedance of LS in of LS in vertical elementsvertical elements

A b ilt fi dkN

)As-built, fixedAs-built, upliftRetrofitted, fixedRetrofitted, uplift

Bas

e sh

ear(

Displacement (m)


Displacement (m)Green: Damage Limitation per EC8-3 Yellow: Significant Damage per EC8-3Red: Near Collapse in bending Purple: Near collapse in shear


As-built, fixedAs-built, uplift

ar(k

N)

Retrofitted, fixedRetrofitted, uplift

Bas

e sh

ea



Pushover analysis Pushover analysis ±±Χ, Χ, ±±ΥΥ, fixed v uplifting footings,, fixed v uplifting footings,PGA at 1PGA at 1stst exceedance of Limit State in exceedance of Limit State in beamsbeams

kN)


Bas

e sh

ear(

Displacement (m)


Displacement (m)Green: Damage Limitation per EC8-3 Yellow: Significant Damage per EC8-3Red: Near Collapse in bending Purple: Near collapse in shear


As-built, fixedAs built uplift

As-built, fixedAs built uplift

ar(k

N)

As-built, upliftRetrofitted, fixedRetrofitted, uplift

As-built, upliftRetrofitted, fixedRetrofitted, uplift

Bas

e sh

ea


Shear & flexural damage index in retrofitted building for Significant Damage, Shear & flexural damage index in retrofitted building for Significant Damage, li d i l i (fi d f ti / 14 d 0 25 )li d i l i (fi d f ti / 14 d 0 25 )nonlinear dynamic analysis (fixed footings, av/ge over 14 records, 0.25g)nonlinear dynamic analysis (fixed footings, av/ge over 14 records, 0.25g)

Flexure Flexure -- Significant DamageSignificant Damage

ShearShear


Conclusions from retrofitted 2Conclusions from retrofitted 2--storey buildingstorey buildingwith fixed or uplifting footingswith fixed or uplifting footings

Flexural damage indices at column bases are reduced compared to as built but the “Significant Damage” Limit State

with fixed or uplifting footingswith fixed or uplifting footings

compared to as-built, but the “Significant Damage” Limit State still not met.

Adding new walls does not prevent failure of the interior large wall.

Flexural damage indices in beams increase compared to the as-built

R t fit ith ll t th i t i i ffi i tRetrofit with new walls at the perimeter is insufficient. Additional retrofit of other members w/ FRP jackets is necessary; it turns out to be very cost-effective


necessary; it turns out to be very cost effective.

Cost of retrofitting 2Cost of retrofitting 2--storey building storey building (considered with uplifting footings)(considered with uplifting footings)(considered with uplifting footings)(considered with uplifting footings)

Wall Starter bars plus dowels Dowels doubling as starter bars ΤΝ1 6730 € 4550 €

Cost of added walls:@ 90€ / 3 t ΤΝ2 2470 € 2230 €

ΤΝ3 1720 € 1640 €

ΤΝ4 1230 € 1230 €

@ 90€ /m3 concrete@ 1€ /kg steelepoxy grouting @ 9€/Φ20mm dowel

@ 7€/Φ12mm dowelTotal 12150 € 9650 €

@ 7€/Φ12mm dowel

Cost of addingCFRP

Vertical element Story DI to be made <1.0 required v provided CFRP Cost €

Column 7 1st - base 1.11 0.184mm → 2 plies 0.24mm 60 CFRPs:@ 40€ /m2 CFRP ply

p

Column 7 2nd - base 1.23 0.364mm → 3 plies 0.36mm 90

Column 17 1st - base 1.01 0.005mm → 1 ply 0.12mm 25



Column 39 1st base 1 04 0 02mm → 1 ply 0 12mm 25Column 39 1 - base 1.04 0.02mm → 1 ply 0.12mm 25

central wall 1st - base 1.49 1 ply, 100mm strips / 125mm 2200

central wall 2nd - base 1.09 1 ply, 50mm strips / 250mm 400


Total 2850

Thank you !Thank you !Thank you !Thank you !


Documents

Seismic Rehabilitation of Concrete Buildings byyg y Converting …2... · 2012-04-27 · ¾Often by filling bay of existing frame, encapsulating its beams & columns. ¾“Collector