DIANA使用非线性有限元模型进行结构评估

Structural

Assessment

of

anExistingHeritage

StructurePrepared

by:Krishnachandran

SMastersStudentResearchGuide:

Dr.

Arun

MenonAssistantProfessorStructural

Engineering

LaboratoryDepartment

of

Civil

EngineeringIndian

Institute

of

Technology

Madras2Contents•

Section

1-

Description

on

the

Structure

Under

Investigation•

Section

2-

Possibilities

of

Modelling

Masonry

Buildings

inDIANA

considering

the

example

of

a

three

walled

openstructure•

Section

3-

Modelling

and

Analysis

of

Existing

MasonryStructure

in

DIANA

using

smeared

macromodelling•

Section

4-

Component

Level

Analysis

using

Discrete

InterfaceModel3Contents•

Section

1-

Description

on

the

Structure

Under

Investigation•

Section

2-

Possibilities

of

Modelling

Masonry

Buildings

inDIANA

considering

the

example

of

a

three

walled

openstructure•

Section

3-

Modelling

and

Analysis

of

Existing

MasonryStructure

in

DIANA

using

smeared

macromodelling•

Section

4-

Component

Level

Analysis

using

Discrete

InterfaceModel4Out-of-PlaneMechanisms•

LocalMechanisms•

Associatedwiththelocalresponseofstructuralelements

ormacro

elements•

They,in

turncancauseadropin

global

loadcarryingcapacity5Brief

Description

onthe

StructureChosenAssessment

ofastructure

vulnerable

toout-of-planecollapse6Details

of

the

BuildingPLANEAST

SIDEELEVATIONACTUAL

BUILDINGSOUTHSIDE

ELEVATION7Contents•

Section1-

DescriptionontheStructureUnder

Investigation•

Section2-PossibilitiesofModelling

Masonry

Buildings

inDIANA

considering

theexampleofathreewalled

openstructure•

Section3-Modelling

andAnalysis

ofExistingMasonryStructurein

DIANA

usingsmearedmacromodelling•

Section4-ComponentLevel

Analysis

usingDiscreteInterfaceModel83

Questions…Whatarethepossibilitiesformodelling

seismicbehaviourmasonryeffectively

?Howdoes

themodelingstrategiestakeout-of-planemechanisms

intoconsideration?NonLinearStatic&NonLinearDynamicHowdodifferent

analysisprocedures

compare

themechanisms

generated?9Modelling

StrategiesDetailedMicromodellingSmearedMacromodellingSimplified

Micromodelling10NumericalModellingStrategiesforMasonryMesomodellingMicromodellingMacromodelling‘Simplified

micromodelling’‘DetailedMicromodelling’Units

and

mortar

aresmearedoutEach

jointlumpedintoanequivalentinterfaceEquivalentProperties&PrincipleofhomogenizationProperties

ofbothunitandmortarused11NLFEM-

DIANA•

PlaneStress

Elements

–Co

ordinates

oftheelement

shouldbe

inone

plane.Forcemustactin

theplane

oftheelement.Stress

componentsperpendicular

tothefaceare

zero•

SolidElements-General

Purposeelements.Cancauselargesystem

ofequations.Usedonlywhen

other

elements

areineffective•

Shellelements-

Combinationofplane

stress

element

andplatebending

element12NLFEM-

DIANA•

In-plane

response

of

masonry

wall

was

adequately

capturedby

a

plane

stress

element•

Both

flat

shell

and

curved

shell

elements

can

be

used

for

a3Dmodel•

Why

they

are

used?•

What

are

their

relative

advantages

and

disadvantages?13NLFEM-

DIANA•

Thepoint

atwhich

theusageofflatshellelements

andcurved

shellelements

make

adifference…Flatshell

ElementCurved

ShellElement3

translations,3rotations3

translations,3rotationsAllcoordinates

ofthememberliein

Allcoordinates

ofthememberneedthesameplanenot

lieinthesameplaneForces

inalldirectionsForces

inalldirectionsMoment

mustactintheplaneof

theelementMoment

mustactabout

anaxiswhich

isintheelementface14Model

for

StudyRef:LourencoP.B.

etal.

(2013),

Methodsand

challenges

ontheout-of-planeassessment

of

existing

masonrybuildings,

Pre-

ConferenceWorkshop,9thInternational

MasonryConference,Guimares,

Portugal15NLFEM-DIANAGeometryofthemodelAppropriateMaterialModelAnalysis•

FlatshellorCurvedshell•

NonLinearStatic/Non•

‘CombinedCrackingShearingCrushing’model,‘Rankine-HillAnisotropic’etcelementsusedformodellingLinearDynamic16WhatHappens

in

3Dmodelling?Formation

ofcollapse

mechanisms•

Which

allmechanismsareformed?•

When?•

Howdoesthestructure

performglobally?PossibleApproachesInPlaneWalls

-FlatShellElement

&OutOfPlaneWalls

CurvedShellElementsOnlyCurvedShellElements17How

Modelling

was

Carried

Out?18Creating

Geometry19Geometry

After

Intersect20Meshing21Element

Properties

andMaterialProperties22Combined

CrackingShearingCrushing23Combined

Cracking

Shearing

Crushing

ModelParameterEquation(Lourenco,1996)ValuesModulusofElasticity(E)--5170MPa5MpaMasonryCompressiveStrength(fm)Density(ρ)-1890kg/m3Cohesion(c)Friction

Angle-0.2320tanφ=0.75Gfc15+0.43f

-0.0036f

216N/mm0.012

N/mm0.02

N/mm83.5N/mm3mmGt(mode1)Gt(mode2)kn0.012c/10Eu

Ekn

=jhj

(Eu

Ej

)−ktGuGj39.5N/mm3kt=hj

(Gu

Gj

)−11Κp(0.002

−

f

(+))

fm0.03mm9m

Ek

(h

+

h

)unujCs924Crack

Properties25Meshing

of

Planar

Elements26Creating

Interface

Elements27Model

with

Interface

Elements28Representation

of

English

Bond29Simulating

Rigid

Diaphragm30Simulating

Rigid

Diaphragm31Simulating

Rigid

Diaphragm32BoundaryConditions33Loads-

Self

Weight34Loads-External35BoundaryConditions

and

Loads36Analysis37Analysis38Analysis39Eigen

Values0.10

s0.10s40Flat

shell+Curved

shell41'Load

-Displacement'

curve

(

Flatshell+Curvedshell)140000120000100000800006000040000200000124kNWholeStructureWall

with

Opening(Inplane)Wall

without

Opening(Inplane)Outof

planewall00.511.522.533.54Displacement(mm)42Model-Curved

Shell

Only43‘Force-Displacement’-Curved

Shell

OnlyPushover

Analysis-'CurvedShell'120000100000800006000040000200000110

kNWholeStructureWall

with

Opening(Inplane)Wall

without

Opening(Inplane)Outof

planewall00.511.522.53Displacement(mm)44‘Force-Displacement’-Curved

Shell

Only45Deformed

ProfileShear

Slidingfollowed

byout

of

planemovementOutof

planemovementof

thefacadeDiagonalCrackingfollowed

byout

of

planemovement

oftheblockExpected

Mechanisms

at

different

PGAsPGA0.38g0.58g1.1gExpectedMechanismDiagonalShearShearSliding

initiationFailureofreturnwallsdue

toslidingshearanddiagonalcracking47Influence

of

Diaphragm48Effect

of

DiaphragmsPushovercurve(withouttoprestraint)4500040000350003000025000200001500010000500040kNonly!!000.20.40.60.811.21.4Displacement(mm)49Incremental

Dynamic

AnalysisInputGroundMotion0.50.40.30.20.10051015202530354045-0.1-0.2-0.3-0.4-0.5Time(s)Northridge

Earthquake50Incremental

Dynamic

AnalysisScaling

factorDisplacement(mm)Sa(interms

of'g')00.51000.060.120.190.370.560.741.011.520.180.240.3516.692.530.37Displacement

drastically

increasingbeyond

aspectral

acceleration

ofabout12m/s251Static

Pushover

Versus

IDAPeak

LoadmatchingStatic

Pushover

Analysis

versus

IDA18016014012010080Static

pushoverida

1ida2ida36040200024681012141618Post

peak-Not

Matching…Displacement(mm)52Static

Pushover

Versus

IDA-Initial

PartIncremental

Dynamic

Analysis140120100Static

pushover806040200ida1ida2ida300.10.20.30.40.50.6Displacement(mm)53Progressive

BehaviourStep4-2.75Step

3-1.5Step

2-1Step1-0.554InferenceRightChoiceofElement-’Curvedshell’Effectoflack

ofDiaphragm-63%drop

inLoadInputParametersforModellingCarryingCapacityElasticRegion-StaticPushover

andIDAMatchesPostPeak-StaticPushoverandIDADisagree55InferenceShear

Sliding

followed

byoutofplane

movementOut

of

planemovementof

thefacadeDiagonal

Cracking

followedby

outofplane

movementoftheblock120000'Load-Displacement'curve(Curved

Shell)100000800006000040000200000Contributionto

lateral

load0123carryingcapacityfromoutofplanewalls

inastructurewithlessredundantsissignificant!Displacement(mm)56Whatarethepossibilities

formodelling

seismicresponseofmasonryeffectively?Howdoesthedifferentanalysisprocedurescomparein

termsofmechanismsgenerated?Does

thegeneratedmechanismsagreewiththeonesfrom‘equivalentframe’approach’?57Contents•

Section1-

DescriptionontheStructureUnder

Investigation•

Section2-PossibilitiesofModelling

Masonry

Buildings

inDIANA

considering

theexampleofathreewalled

openstructure•

Section3-Modelling

andAnalysis

ofExistingMasonryStructurein

DIANA

usingsmearedmacromodelling•

Section4-ComponentLevel

Analysis

usingDiscreteInterfaceModel58NLFEM-

DIANA•

Possibletomake

anexhaustivestudyofthewholestructure•

Moresophisticatedmaterialmodelsavailable•

Abletocapture

theactual

responsemoreaccuratelyAre

we

‘offtarget’

if‘Equivalent

Frame

Approach’isadopted?Ifso,bywhatmargin?Isitworthy

ofadopting

a‘computationally

expensive’finite

element

approach?59Existing

Masonry

Structure•

Variabilities

in

structural

configurationswithinabuilding•

Retrofitofexisting

constructions-relevant

topic

in

presentscenario•

Theimportanceoflocalmechanisms

notproperly

addressed•

But,canwell

be

thegoverning

factorwhile

adopting

retrofitstrategies60Global

Level

Analysis•

Analysiscarriedout

usingequivalent

frameapproach

aswellascontinuum

finiteelement

modellingapproach.•

Concerns-

Global

lateralloadanddeformationcapacities

ofthestructure,indicationsofthepossiblemechanisms

thatcanarise.GlobalLevelAnalysisContinuum

FiniteElement

ModellingEquivalentframeapproach61Equivalent

Frame

Approach•

Software-

3muri•

Wallssubdivided

into

piers

and

spandrels

(‘macroelements’)Ref:

Lagomarsino

S.,PennaA.,Galasco

A.,CattariS.(2013),

“TREMURIProgram:

Anequivalentframemodel

forthenonlinear

seismic

analysis

ofmasonry

buildings”,EngineeringStructures,

1787-179962Modelling63Importing

Geometry64Importing

Geometry65Meshing66Meshing67NLFEM•

Model-Rankine

Hill

anisotropicParametersValuesElastic

Modulus2000MPa3MPaCompressive

strengthTensilestrength0.1MPa0.1MPaInitialshearstrengthTensilefractureenergyCompressive

fractureenergyPlastic

strain0.012N/mm16.25N/mm0.00368How

Rigid

Diaphragm

wasIncorporated?69Analysis70Eigen

Analysis71Pushover

Analysis72Results73Global

Level

Analysis

of

theStructure•

Deadloadstress-

Maximum-0.5MPa•

Eigen

Value

Analysis0.26s,

77%participation(NLFEM)0.23s,

77%participation(EFM)74Pushover

Analysis-

Capacity

curves•

'Baseshear-Top

Displacement'•

NLFEMEquivalentFrameApproach800070006000500040003000200010000800070006000500040003000200010000010203040500102030TopDisplacement

(mm)TopDisplacement(mm)PeakLoad-5800kNPeakLoad-7500kN75Effect

of

Rigid

Diaphragm0.20.180.160.140.120.1withouttying0.080.060.040.020withtyings010203040Displacement(mm)Plastic

strainsinpiers

duetoout

of

planedisplacements.76Effect

of

Rigid

DiaphragmShowingidealbehaviourand

crackpropagation-unrealistic77Damage

Propagation-

FlexibleDiaphragm78Damage

Propagation-

RigidDiaphragm79Damage

PropagationRigid

DiaphragmFlexible

Diaphragm80Comparison

of

Results-

StrongerDirectionCourtesy:JacobAlexKollerathu,PhD

Scholar,

IIT

Madras81Comparison

of

Results-

WeakerDirectionCourtesy:JacobAlexKollerathu,PhD

Scholar,

IIT

Madras82Contents•

Section1-

DescriptionontheStructureUnder

Investigation•

Section2-PossibilitiesofModelling

Masonry

Buildings

inDIANA

considering

theexampleofathreewalled

openstructure•

Section3-Modelling

andAnalysis

ofExistingMasonryStructurein

DIANA

usingsmearedmacromodelling•

Section4-ComponentLevel

Analysis

usingDiscreteInterfaceModel83Local

MechanismsLocal

mechanismsDiscrete

Interface

ModelThe

macroblockwhichissusceptible

tofailureismodelled

rigorously.Undertheaction

ofthesameload,itischeckedfor

theoccurrence

ofpossiblelocal