présentation orange foncé avec photo - code aster 4 outline 1. modeling of the reinforced concrete...

FORMATION ITechCode_Aster et Salomé-

Méca –

module 4 : Génie Civil(ARN3960)

Recherche & Développement

24-25 mai 2018

Copyright © EDF 2018 – S. Michel-Ponnelle

| 2Aster Génie Civil | 24/05/2018

Part 2 –

Modeling of the

prestressed

reinforced

concrete

| 3

OUTLINE

MODELING OF THE REINFORCED CONCRETE

MODELING OF THE PRESTRESSED CONCRETE

Aster Génie Civil | 24/05/2018

| 4

OUTLINE

1. MODELING OF THE REINFORCED CONCRETE

IN A 3D MODEL

IN A 2D MODEL

IN A 1D MODEL

WITH A GLOBAL MODEL

2. MODELING OF THE TENDONS



MODELING THE STEEL IN REINFORCED CONCRETE :

IN A 3D MODEL

Option #1 : use the BARRE model (or if needed POU_D_T)

Mesh steels with SEG2 elements

Behavior is 1D

Steel and concrete nodes must be identical

Perfect bond between steel and concrete

| 6

Option #2 : use the GRILLE_MEMBRANEmodel

Steel is meshed with 2D elements : QUAD4, TRIA3, QUAD8, TRIA6



Behavior law 1D (GRILLE_ISOT_LINE, ...)

Overlay meshes for different directions of reinforcement (CREA_MAILLAGE

or duplication in Salomé )



IN A 3D MODEL

| 7

Option #3 : use the MEMBRANEmodel

Steel is meshed with 2D elements : QUAD4, TRIA3, QUAD8, TRIA6



Orthotropic behavior law : ELAS only



IN A 3D MODEL

| 8

Option #4 : use the 3D model

Steel is meshed with 3D elements

Perfect bond between steel and concrete if nodes are identical.

Behavior law : no restriction



IN A 3D MODEL

| 9

Modeling the decohesion steel/concrete

introduction of 3D_INTERFACE elements between concrete 3D and steel 3D or

MEMBRANE

the behavior law CZM_LAB_MIX



IN A 3D MODEL

INTERFACE

CONCRETE

STEEL

CONCRETE CONCRETE

STEEL

INTERFACE

| 10


IN A 2D MODEL (PLAN OR AXIS)

Option #1 : use the 2D_BARRE model Steel meshed with SEG2 elements


Behavior is 1D

Option #2 : use the 2D model Steel is meshed with 2D elements

Behavior law : no restriction


(decohesion by introducing X_JOINT elements with JOINT_BA law)


2D/2D


MODELING THE STEEL IN REINFORCED CONCRETE :WITH A SHELL MODEL (DKT)

Use GRILLE_EXCENTREE

Steel meshed with linear 2D elements : QUAD4 or TRIA3

Overlay meshes for different directions of reinforcement (CREA_MAILLAGE

or duplication in Salomé )


Behavior law 1D (GRILLE_ISOT_LINE, ...)

CONCRETE

Acier V_2

Acier H-2

Acier V-1

Acier H -1


SOME DETAILS FOR MEMBRANE, GRILLE_MEMBRANE,

GRILLE_EXCENTREE : COMPARISON

MEMBRANE GRILLE_MEMBRANE GRILLE_EXCENTREE

unknowns Displacement Displacement Displacement + rotation

rigidity orthotropic 1D 1D

Behavior law ELAS GRILLE_xxxx GRILLE_xxxx

eccentricity No No yes

PropertyDEFI_MATERIAU

ELAS_MEMBRANE ELAS, … ELAS, …

PropertyAFFE_CARA_ELEM

MEMBRANE/

ANGL_REP or

AXE

GRILLE/

SECTION (m2/ml)

ANGL_REP or AXE

GRILLE/

SECTION (m2/ml),

EXCENTREMENT,

ANGL_REP or AXE

COEF_RIGI_DRZ

Be careful : for MEMBRANE elements, RHO: r [kg/m3 ]* S[m2/ml]

ANGL_REP_1 or ANGL_REP_2 or VECT_1 or VECT_22018

| 13


GRILLE_EXCENTREE : DUPLICATION OF THE MESH

With Salomé :

Modification /

Transformation /

Duplicate Nodes or/and Elements

With Code_Aster :

CREA_MAILLAGE( MODELE=MO,

CREA_MAILLE=(_F(GROUP_MA = ‘CONCRETE',name of the existing face

NOM = ‘AcierH1', name of the new group

PREF_MAILLE=‘H1')) suffix used for the new mesh

_F(GROUP_MA = ‘CONCRETE',

NOM = ‘AcierV1',

PREF_MAILLE=‘V1')

…)Aster Génie Civil | 24/05/2018

Concrete

Acier V2

Acier H2

Acier V1

Acier H1

| 14


GRILLE_EXCENTREE : LOCAL DIRECTIONS

Definition of the local directions (X1,Y1,Z1) of the elements

in AFFE_CARA_ELEM

Option 1 : ANGL_REP= (a, b) to define X1

Option 2 : AXE= V (vx,vy,vz) to define Y1


For instance :

If X1= X : (0,0)

If X1= Y : (90,0)

For a hemisphere : ZZZZ189

Define X1 : ANGL_REP_1 or VECT_1

Define X2 : ANGL_REP_2 or VECT_22018

| 15


GRILLE_EXCENTREE : RESULTS

Comparison on a flexural test

(perfect adhesion of the bars)

Excellent results with the membrane model

Satisfactory results with the grid model


Model Displacement Discrepancy

Reference model

(3D)

87.1 µm

Concrete only 119 µm 37 %

Concrete + Grid

model

84 µm 3.6 %

Concrete +

Membrane model

87.3 µm 0.2 %

(900 000 dof)

| 16

Use of multi-fiber beam POU_D_EM/POU_D_TGM

MESH 1D + Definition of the section of the beam : mesh/point by point (DEFI_GEOM_FIBRE)



FOR A 1D MODEL


MODELING THE REINFORCED CONCRETE WITH A

GLOBAL MODEL

DKTG elements and a global constitutive law

GLRC_DM (moderate damage, symetrical reinforcements)

DHRC (moderate damage+ cracking)

GLRC_DAMA (damage for impact)

Advantage : more robust (no softening) especially for dynamic analysis

Typical response in tension for GLRC_DM


OUTLINE

Modeling of the reinforced concrete

Modeling of the prestressed concrete

Principles

Modeling the grouted tendon with DEFI_CABLE_BP/CALC_PRECONT

Modeling the ungrouted tendon with DEFI_CABLE_BP/CALC_PRECONT

| 19

MODELING OF THE PRESTRESSED CONCRETE:

PRINCIPLES

Post-tensioning

Tension in the tendon is not a constant, neither in space nor in time :

in space : friction, elastic strains, slip, …

in time : relaxation of steel, delayed strains in the concrete, … The behavior is

different the tendon is grouted or not :

-> perfect bond between steel and concrete or friction model


1 strand = 7 wires

n strands = 1 tendon with n [1;55]

| 20

MODELING OF THE PRESTRESSED CONCRETE:

PRINCIPLES

Mesh of the tendon: With 3D elements

With (GRILLE_)MEMBRANE

(2D)

With 1D element

Tensioning of the tendon: PRE_EPSI

Fictive thermal strain

Sophisticate tools available in

Code_Aster !


| 21

Modeling of THE PRESTRESSED CONCRETE:

principles

If tendons = 1D elements embedded in a 3D or DKT mesh,

specific tools DEFI_CABLE_BP/CALC_PRECONT enable :

- to use a steel mesh independent of the concrete mesh

- to take into account the tension’s losses in the

tendon such as friction

- ...

2 types of elements are available :

BARRE for grouted tendons

CABLE_GAINE for ungrouted tendons



OUTLINE



Principles



| 23

MODELING OF THE GROUTED TENDON

METHODOLGY

The DEFI_CABLE_BP command creates loads

corresponding to :

The link (assumed perfect) between the tendon and the concrete :

automatic definition of Lagrange multipliers

The calculation of tension in the cables as recommended by

BPEL/ETCC

The CALC_PRECONT command applies the tension


GRI GRFN1 N6N5N4N3N2

cable1[U4.42.04]


MODELING OF THE GROUTED TENDON : PRESCRIBED

FORMULA FOR THE TENSION IN THE TENDONS

tension at any point of the cable as recommended by BPEL91

F (s)= F̃ (s)− {x flu× F 0+ x ret× F 0+ r ( j)×5

100× ρ1000[F̃ (s)

S a× f prg

− μ0]× F̃ (s)}

F c (s)= F 0exp (− f α− ϕs)

F c (s)× F̃ (s)= [F c(d )]2

Taking into account the instantaneous losses by friction and anchor recoil


MODELING OF THE GROUTED TENDON : PRESCRIBED

FORMULA FOR THE TENSION IN THE TENDONS

tension at any point of the cable as recommended by BPEL91

F (s)= F̃ (s)− {x flu× F 0+ x ret× F 0+ r ( j)×5

100× ρ1000[F̃ (s)

S a× σ y

− μ0]× F̃ (s)}

Taking account of losses depending on time

Creep of concrete

Relaxation of steel(ETCC BPEL)

Shrinkage of concrete

| 26

MODELING OF THE GROUTED TENDON :

DATA SETTINGSMBETON=DEFI_MATERIAU(ELAS=_F(E= 30.E9,...),

BPEL_BETON= _F( ◊ PERT_FLUA = 0,

◊ PERT_RETR = 0),);

MCABLE=DEFI_MATERIAU(ELAS=_F(E=200.E9 ),

BPEL_ACIER=_F( ◊ FROT_COURB =3.0E-3,

◊ FROT_LINE =1.5E-3,

◊ F_PRG =1.94E11,

◊ RELAX_1000 = 0,

◊ MU0_RELAX = 0),)

in DEFI_CABLE_BP

in AFFE_CARA_ELEM

ETCC_BETON=_F()

ETCC_ACIER=_F(◊ COEF_FROT

◊ PERT_LIGNE

◊ F_PRG

◊ RELAX_1000


F0, Δ , r ( j)

S a

| 27


cable1


MODELING OF THE GROUTED TENDONDEFI_CABLE_BP COMMAND

cabl_pr = DEFI_CABLE_BP (

♦ MODELE = modele,

♦ CHAM_MATER = chmat,

♦ CARA_ELEM = caelem,

♦ GROUP_MA_BETON = grmabe, Required for kinematic links







♦ GROUP_MA_BETON = grmabe,

♦ TENSION_INIT = f0,

♦ RECUL_ANCRAGE = delta,

◊ ADHERANT = ‘OUI’ (‘NON’)

◊ TYPE_RELAX = ‘SANS’/’BPEL’/’ETCC_DIRECT’/’ETCC_REPRISE’

◊ R_J/NBH_RELAX

Characteristics of the tendon for the tension estimation


cable1












◊ R_J/NBH_RELAX

♦ DEFI_CABLE = _F (

♦ GROUP_MA = cable1,

♦ GROUP_NO_ANCRAGE = (‘GRI’,’GRF’),)

♦ TYPE_ANCRAGE = (‘ACTIF’, ‘PASSIF’),

◊ TENSION_CT

Definition of the tendon(s)


cable1












◊ R_J/NBH_RELAX

♦ DEFI_CABLE = _F (

♦ GROUP_MA = cable1,

♦ GROUP_NO_ANCRAGE = (‘GRI’,’GRF’),

♦ TYPE_ANCRAGE = (‘ACTIF’, ‘PASSIF’),

◊ TENSION_CT

◊ CONE = _F ( ♦ RAYON = rayon,

♦ LONGUEUR = long,

♦ PRESENT = ('OUI','NON'))

]

Definition of the « diffusion cone »


cable1

[U4.42.04]


MODELING OF THE GROUTED TENDON:

POTENTIAL DIFFICULTIES


MODELING OF THE GROUTED TENDON:

“DIFFUSION CONE”

Possibility of introducing a diffusion cone

Real situation Without modelling the shaft With modeling of the

effect of shaft vanishing

mesh size required

management of redundant boundary conditions

[U4.42.04]


MODELING OF THE GROUTED TENDON

METHODOLGY

The AFFE_CHAR_MECA command defines the effective loads

CAB1 = DEFI_CABLE_BP (...)

CMCAB=AFFE_CHAR_MECA(

MODELE=MO,

RELA_CINE_BP=_F(CABLE_BP=CAB1,

SIGM_BPEL=‘OUI' or 'NON',

RELA_CINE='OUI' or 'NON'))

Dependant on the strategy used



TWO STRATEGIES

Strategy #1

chcab=AFFE_CHAR_MECA(...

RELA_CINE_BP=_F(

CABLE_BP=cable,

SIGM_BPEL=‘OUI',

RELA_CINE='OUI'))

RES1 = STAT_NON_LINE(...

EXCIT=(_F(CHARGE = CLIM,),

_F(CHARGE = chcab)),

...,)

Strategy #2

chcab =AFFE_CHAR_MECA(...

RELA_CINE_BP=_F(

CABLE_BP=cable,

SIGM_BPEL=‘NON',

RELA_CINE='OUI',),);

RES1 = CALC_PRECONT(...

EXCIT=(_F(CHARGE =CLIM,),),

CABLE_BP=cable,

...,)



TWO STRATEGIES

STAT_NON_LINE

Loss of tension due to the

instantaneous strain of the concrete

No stages for the prestress loading

Easier implementation

Tensions le long du câble

0,E+00

1,E+06

2,E+06

3,E+06

4,E+06

5,E+06

6,E+06

1 11 21 31 41 51 61 71 81 91 101 111 121 131

Elément

Tensio

n (

N)

BPEL DCBP sans correction DCBP après correction

CALC_PRECONT

Final tension in cables =

BPEL/ETCC

Allows prestress loading stages

A little more complex

Strategy #1 :

STAT_NON_LINE

Strategy #2 :

CALC_PRECONT


MODELING OF THE GROUTED TENDON : CALC_PRECONT COMMAND

statnl [evol_noli] = CALC_PRECONT(

◊ reuse = statnl, ◊ ETAT_INIT = _F(…)

♦ MODELE = mo ,

♦ CHAM_MATER = chmat ,

♦ CARA_ELEM = carac ,

♦ COMP_INCR = _F()

♦ INCREMENT =_F( ♦ LIST_INST = litps ,

◊ INST_FIN = instfin,),

♦ EXCIT =(_F( ♦ CHARGE = chi ), ),

♦ CABLE_BP = cabl_pr ,

◊ CABLE_BP_INACTIF = cabl_pr ,

+ mot-clé facteur STAT_NON_LINE)

The tendons that will be prestressedbetween instini and instfin

Inactive tendons (no stiffness)

Boundary conditions, instant loads,

kinematic links related to tendons

already prestressed

[U4.42.05]



EXAMPLE

CAB_BP=DEFI_CABLE_BP(...)

CH_L=AFFE_CHAR_MECA(MODELE=MO,

RELA_CINE_BP=_F(CABLE_BP=CAB_BP,

SIGM_BPEL=‘NON', RELA_CINE='OUI'));

EVOL = CALC_PRECONT(CABLE_BP = CAB_BP,

EXCIT = _F(CHARGE = CL),

INCREMENT =_F(LIST_INST=L,

INST_FIN = 1.,

…)

EVOL = STAT_NON_LINE(reuse =EVOL,

ETAT_INIT =_F(EVOL_NOLI= EVOL)

EXCIT=(_F(CHARGE= CL),

F(CHARGE=CH_L),

Define the tendon

Define the load :CH_L contains the

kinematic links



EXAMPLE


CH_L=AFFE_CHAR_MECA(MODELE=MO, RELA_CINE_BP=_F(CABLE_BP=CAB_BPi,

SIGM_BPEL=‘NON', RELA_CINE='OUI',),);




INST_FIN = 1.,

…)




F(CHARGE=CH_L),

….

Tensioning of tendons defined in CAB_BP, from t= 0 to 1

Loads : only boundary conditions + instant loads



EXAMPLE


CH_L=AFFE_CHAR_MECA(MODELE=MO, RELA_CINE_BP=_F(CABLE_BP=CAB_BPi,

SIGM_BPEL=‘NON', RELA_CINE='OUI',),);




INST_FIN = 1.,

…)




F(CHARGE=CH_L),

….Continuation of the calculation

Load : boundary conditions + kinematiclinks related to the tendons + other loads

| 40

MODELING OF THE TENDON :

TIPS

The discretization of the concrete and the steel should be similar (one node of

steel in every cell of concrete)

Combine a maximum tendons in DEFI_CABLE_BP

Option CONE : Pay attention to redundant connections (not factorable matrix) +

size of elements

If TYPE_ANCRAGE = ('PASSIF', 'PASSIF'), there is no tension in the cable !

For strategy#1, in case of a continuation calculation (POURSUITE), define a new

load without tension, otherwise the two tensions will be added

In case of non-linear simulation, pay attention to the loss you want to take into account with DEFI_CABLE_BP

For prestress loading stages, you can alternate STAT_NON_LINE and

CALC_PRECONT, but pay attention to the loads to be taken into account !

see documentation U2.03.06 or practical session or test FORMA42Aster Génie Civil | 24/05/2018


OUTLINE



Principles



| 42

MODELING OF THE UNGROUTED TENDON /

GROUTED TENDON : MAIN DIFFERENCES


GROUTED UNGROUTED

MESH SEG2 SEG3

MODELING BARRE CABLE_GAINE

Behavior law ELAS, VMIS_ISOT_LINE, … KIT_DDI : a law for the

tendon + CABLE_GAINE_FROT

Prestressing STAT_NON_LINE orCALC_PRECONT

CALC_PRECONT only

Tension Prescribed formula Obtained by the

calculation

| 43

MODELING OF THE UNGROUTED TENDON

SPECIFICITIES (1/2)

DEFI_MATERIAU (CABLE_GAINE_FROT =

_F(TYPE= ‘FROTTANT’,

FROT_COURBE = xx,

FROT_LINE = xxx,

PENA_LAGR = XXX))

Choice of PENA_LAGR is important. It can be estimated by : 2𝜋𝑟𝑐𝑎𝑏𝑙𝑒𝜎𝑟𝑒𝑓

𝑢𝑟𝑒𝑓

AFFE_CHAR_MECA()

You have to think to enforce a condition on the anchorage nodes (GLIS)


U

GLIS

l

U

GLIS

l

U

GLIS

| 44

MODELING OF THE UNGROUTED TENDON

SPECIFICITIES (2/2)

EVOL=CALC_PRECONT (

CABLE_BP= CABLE1,

COMPORTEMENT =( _F(RELATION = ‘KIT_GC’,

KIT_DDI =(‘ELAS’,

‘CABLE_GAINE_FROT’),

GROUP_MA = CABLE),

_F(RELATION=‘ELAS’,

GROUP_MA=‘BETON’)),

CONVERGENCE = _F(RESI_REFE_RELA= 1.E-6,

EFFORT_REFE = 1.E5,

MOMENT_REFE = 1.0,

SIGM_REFE = 1.E6,

DEPL_REFE = 1.E-1)

…

The convergence could be difficult : the displacement is enforced with

only one step time + one for each slip at the anchorage.

Use RESI_REFE_RELA for the convergence criterion



THANKS


End of presentation

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présentation orange foncé avec photo - code aster 4 outline 1. modeling of the reinforced concrete...

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