3. example#
Here we detail the main steps of a structural calculation containing prestress cables (test case SSNV164)
3.1. Before using the macro command#
Cable definition
In case of non-simultaneous voltage of all cables, it is necessary to do (at least) as many DEFI_CABLE_BPque of charging steps.
CAB_BP1 = DEFI_CABLE_BP (MODELE =MO,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
GROUP_MA_BETON =” VOLTOT “,
DEFI_CABLE =( _F (GROUP_MA =” CAB1 “,
GROUP_NO_ANCRAGE =( “PC1D”, “PC1F”,),
TYPE_ANCRAGE =( “ACTIF”, “PASSIF”,),),
_F (GROUP_MA =” CAB2 “,
GROUP_NO_ANCRAGE =( “PC2D”, “PC2F”,),
TYPE_ANCRAGE =( “ACTIF”, “PASSIF”,),),),
TENSION_INIT =3.750000E6,
RECUL_ANCRAGE =0.001,)
CAB_BP3 = DEFI_CABLE_BP (MODELE =MO,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
GROUP_MA_BETON =” VOLTOT “,
DEFI_CABLE =( _F (GROUP_MA =” CAB3 “,
GROUP_NO_ANCRAGE =( “PC3D”, “PC3F”,),
TYPE_ANCRAGE =( “ACTIF”, “PASSIF”,),),
_F (GROUP_MA =” CAB4 “,
GROUP_NO_ANCRAGE =( “PC4D”, “PC4F”,),
TYPE_ANCRAGE =( “ACTIF”, “PASSIF”,),),),
TENSION_INIT =3.750000E6,
RECUL_ANCRAGE =0.001,)
CAB_BP5 = DEFI_CABLE_BP (MODELE =MO,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
GROUP_MA_BETON =” VOLTOT “,
DEFI_CABLE =_F (GROUP_MA =” CAB5 “,
GROUP_NO_ANCRAGE =( “PC5D”, “PC5F”,),
TYPE_ANCRAGE =( “ACTIF”, “ACTIF”,),),
TENSION_INIT =3.750000E6,
RECUL_ANCRAGE =0.001,
)
Load definition
A distinction must be made between:
**loads linked to boundary conditions plus any instant uploads,*
the loads linked to cables containing only the kinematic links,
non-instantaneous loads after the cables have been tensioned.
CLIM = AFFE_CHAR_MECA (MODELE =MO,
DDL_IMPO =(
_F (GROUP_NO =”PP”,
DX=0.0, DY=0.0,),
_F (GROUP_NO =”PX”,
DY=0.0,),
_F (GROUP_NO =”PY”,
DX=0.0,),
_F (GROUP_NO =” SU3 “,
DZ=0.0,),),),
PESANTEUR =( 9.81,0.0,0.0, -1.0,),)
CMCAB1 = AFFE_CHAR_MECA (MODELE =MO,
RELA_CINE_BP =_F (CABLE_BP = CAB_BP1,
SIGM_BPEL =” NON “,
RELA_CINE =” OUI “,),)
CMCAB3 = AFFE_CHAR_MECA (MODELE =MO,
RELA_CINE_BP =_F (CABLE_BP = CAB_BP3,
SIGM_BPEL =” NON “,
RELA_CINE =” OUI “,),)
CMCAB5 = AFFE_CHAR_MECA (MODELE =MO,
RELA_CINE_BP =_F (CABLE_BP = CAB_BP5,
SIGM_BPEL =” NON “,
RELA_CINE =” OUI “,),)
CHMECA = AFFE_CHAR_MECA (MODELE =MO,
DDL_IMPO =_F (GROUP_NO =” SU2 “,
DZ=1.0,),)
Preliminary calculation before cable tension (optional)
The aim here is to take into account the loads that apply to the structure before the cables are tensioned. In order not to take into account the stiffness of the cables, and not to introduce a loading on the cables, the calculation must be carried out either on a model that does not contain the cables or by assigning them a SANS law of behavior, which requires that the stress remains zero in these elements.
RES1 = STAT_NON_LINE (MODELE =MO,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
COMPORTEMENT =( _F (RELATION = “ELAS”,),
_F (RELATION = “SANS”,
GROUP_MA = (“CAB1”, “CAB3”, “CAB5”),),),
EXCIT =( _F (CHARGE = CLIM,),
_F (CHARGE = CMCAB1),
_F (CHARGE = CMCAB3),
_F (CHARGE = CMCAB5),),
INCREMENT =_F (LIST_INST = LINST,
INST_FIN = 150.),)
3.2. Use of the macro control: successive tension of the 5 cables#
The macro command is used as many times as necessary.
RES1 = CALC_PRECONT (reuse= RES1,
ETAT_INIT =_F (EVOL_NOLI = RES1),
MODELE =ME,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
COMPORTEMENT =( _F (RELATION = “ELAS”,),),
EXCIT =( _F (CHARGE = CLIM,),),
CABLE_BP =( CAB_BP1,),
CABLE_BP_INACTIF = (CAB_BP3, CAB_BP5,),
INCREMENT =_F (LIST_INST = LINST,
INST_FIN = 300. ,
),)
RES1 = CALC_PRECONT (reuse= RES1,
ETAT_INIT =_F (EVOL_NOLI = RES1),
MODELE =ME,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
COMPORTEMENT =( _F (RELATION = “ELAS”,),),
EXCIT =( _F (CHARGE = CLIM,),
_F (CHARGE = CMCAB1,),
CABLE_BP =( CAB_BP3,),
CABLE_BP_INACTIF = (CAB_BP5,),
INCREMENT =_F (LIST_INST = LINST,
INST_FIN = 450. ,
),)
RES1 = CALC_PRECONT (reuse= RES1,
ETAT_INIT =_F (EVOL_NOLI = RES1),
MODELE =ME,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
COMPORTEMENT =( _F (RELATION = “ELAS”,),),
EXCIT =( _F (CHARGE = CLIM,),
_F (CHARGE = CMCAB1,),
_F (CHARGE = CMCAB3,),
CABLE_BP =( CAB_BP5,),
INCREMENT =_F (LIST_INST = LINST,
INST_FIN = 600. ,
),)
3.3. Continued charging after the cables have been tensioned#
The cables being stretched, all that is left is to continue the calculation by always including the kinematic links connecting the cable nodes to the concrete.
RES1 = STAT_NON_LINE (reuse = RES1,
ETAT_INIT =_F (EVOL_NOLI = RES1),
MODELE =ME,
CHAM_MATER = CMAT,
CARA_ELEM =CE,
COMPORTEMENT =_F (RELATION = “ELAS”),
EXCIT =( _F (CHARGE = CLIM,),
_F (CHARGE = CMCAB1),
_F (CHARGE = CMCAB3),
_F (CHARGE = CMCAB5),
_F (CHARGE = CHMECA,
FONC_MULT = FCT,),
INCREMENT =_F (LIST_INST = LINST,),)