3. Operands#
3.1. Operands RESULTAT and CARA_ELEM#
♦ RESULTAT = resu
Name of a result concept of type mult_elas. It is necessarily re-entering.
♦ CARA_ELEM = character
It is necessary to fill in the elementary characteristics with the keyword CARA_ELEM for all static & dynamic results. This change is induced by the integration of POST_COMBINAISON (U4.81.45) which generates a ELAS_MULT result without an associate of CARA_ELEM.
3.2. Operand CODIFICATION#
♦ CODIFICATION = /” EC2 “, [DEFAUT]
/' BAEL91 ',
This is the codification to be used for verifications.: Eurocode 2 (EC2) or BAEL91.
3.3. Operand COMBINAISON#
♦ COMBINAISON = _F (♦ TYPE =/”ELS_QUASIPERMANENT”,
/” ELS_CARACTERISTIQUE “,
/” ELU_FONDAMENTAL “,
/” ELU_ACCIDENTEL “,
♦/NOM_CAS = l_nomcas
/NUME_ORDRE = l_order number,)
With this repeatable operator, the command is provided with the list of cases (results of the mult_elas) on which to carry out the dimensioning which correspond to the service limit state checks (the characteristic combination is the only one available at the moment) and ultimate (fundamental, accidental) checks.
The choice between ELU_FONDAMENTALet ELU_ACCIDENTEL makes it possible to choose the value of the safety coefficients GAMMA (see operand AFFE, § 3.4).
3.3.1. Keyword TYPE#
♦ TYPE =/”ELS_QUASIPERMANENT”,
/” ELS_CARACTERISTIQUE “,
/” ELU_FONDAMENTAL “,
/” ELU_ACCIDENTEL “,
With this keyword, you choose the type of check to associate with the case list. For the time being, the options available are the ultimate fundamental or accidental limit states and the characteristic and almost permanent service limit states as defined by the Eurocodes.
3.3.2. Keywords NUME_ORDRE and NOM_CAS#
Here is provided the list of cases associated with the check entered in TYPE, either as a list of case order numbers or as a list of case names (label associated with each result of the mult_elas).
Note
Here the order number does not indicate a calculation time or a frequency as for the result data structures but a case number (one of the results contained by the multi_elas).
3.4. Operand AFFE#
Many of the keywords entered here are the same as for the CALC_FERRAILLAGE command. A difference with the keywords of CALC_FERRAILLAGE consists in the choice of safety factors:
◊ GAMMA_S_FOND = gs, [R]
◊ GAMMA_S_ACCI = gs, [R]
◊ GAMMA_C_FOND = GC, [R]
◊ GAMMA_C_ACCI = GC, [R]
We will choose the values entered under GAMMA_S_FOND and GAMMA_C_FOND to feed CALC_FERRAILLAGE if the user has chosen option ELU_FONDAMENTAL of the COMBINAISON (§ 3.3) operand for a certain load case. For ELU_ACCIDENTEL, the values of GAMMA_S_ACCI and GAMMA_C_ACCI will be selected.
3.5. Composition of the product field#
The result of each case with name NOM_CAS is enriched by a new field (named “FERRAILLAGE” in the data structure) whose components are:
If TYPE_STRUCTURE = “2D”:
a density of longitudinal reinforcement in the \(X\) direction of the element for the lower face of the element (\(\mathrm{DNSXI}\));
the equivalent for the upper side (\(\mathrm{DNSXS}\));
a density of longitudinal reinforcement in the \(Y\) direction of the element for the lower face of the element (\(\mathrm{DNSYI}\));
the equivalent for the upper side (\(\mathrm{DNSYS}\));
the density of transverse reinforcement in the \(X\) direction of the element (\(\mathit{DNSXT}\));
the equivalent in the \(Y\) sense of the element (\(\mathit{DNSYT}\));
total steel volume density (\(\mathit{DNSVOL}\));
an indicator of the complexity of implementing the reinforcement (\(\mathit{CONSTRUC}\)).
If TYPE_STRUCTURE = “1D”:
a density of longitudinal reinforcement along axis \(Y\) of the section, and in the positive direction of the axis (upper face along the height h) (\(\mathit{AYS}\));
a density of longitudinal reinforcement along axis \(Y\) of the section, and in the negative direction of the axis (lower face along the height h) (\(\mathit{AYI}\));
a density of longitudinal reinforcement along the axis of the section, and in the positive direction of the axis (upper face along the width b) (\(\mathit{AZS}\));
a density of longitudinal reinforcement along axis \(Z\) of the section, and in the negative direction of the axis (lower face along width b) (\(\mathit{AZI}\));
a density of transverse reinforcement (\(\mathit{AST}\));
a total longitudinal reinforcement density (\(\mathit{ATOT}\));
total steel volume density (\(\mathit{DNSVOL}\));
an indicator of the complexity of implementing the reinforcement (\(\mathit{CONSTRUC}\)).
The reinforcement field is calculated for the only time existing for each case. One of the main goals of command COMBINAISON_FERRAILLAGE is to calculate, for each type of reinforcement (longitudinal, transverse, etc.), the dimensioning combination, that is to say the one that maximizes the type of reinforcement in question.
Thus, the algorithm of the command COMBINAISON_FERRAILLAGE calls the command CALC_FERRAILLAGE for each case (order number of mult_elas) by choosing the type of check specified by TYPE_COMB. Then, the reinforcement densities (for each type of reinforcement) are compared with each other; the one that gives rise to the most important reinforcement is the dimensioning combination. This comparison is made each time COMBINAISON_FERRAILLAGE is called, so on each node of the selected mesh groups.
There will therefore be as many dimensional combinations as there will be types of reinforcement.
In the given multi_elas structure, two new cases are created:
COMB_DIME_ACIER → Under this case name the maximum reinforcements for each finite element and type of reinforcement are filled in
COMB_DIME_ORDRE → Under this case name are entered the order numbers of the cases that provide the maximum reinforcements (dimensioning cases) for each finite element and type of reinforcement.
3.6. Errors and alarms#
3.6.1. Errors caused by inconsistency in input parameters#
A check of the consistency of the input parameters is carried out at the beginning of the execution of the COMBINAISON_FERRAILLAGE command. The calculation can be stopped by a fatal error in the following cases:
if no occurrence of the COMBINAISON or AFFE operand is specified.
in the case BAEL91à the ELU FONDAMENTAL: if the keywords GAMMA_S_FOND, GAMMA_C_FOND, FEou FCJ, are not filled in;
in the case BAEL91à the ELU ACCIDENTEL: if the keywords GAMMA_S_ACCI, GAMMA_C_ACCI, FEou FCJ, are not filled in;
in the case BAEL91à the ELS: if the keywords N, SIGS_ELSou SIGC_ELSne are not entered;
in the case BAELà the ELS_QP: if the keywords ALPHA_E, FYK, FCK,,,, SIGC_ELS_QP,, WMAX_INF/SUP (_Y/Z), KT, PHI_X /Y/Z_ INF/SUP are not filled in;
in the case EC2à the ELUFONDAMENTAL: if the keywords GAMMA_S_FOND, GAMMA_C_FOND, FYKou FCK, are not filled in;
in the case EC2à the ELU ACCIDENTEL: if the keywords GAMMA_S_ACCI, GAMMA_C_ACCI, FYKou FCK, are not filled in;
in the case EC2à the ELS: if the keywords ALPHA_E, SIGS_ELS, SIGC_INF/SUP (_Y/Z) _ ELSouFCKne are not filled in;
in the case EC2à the ELS_QP: if the keywords ALPHA_E, FYK, FCK,,,, SIGC_ELS_QP,, WMAX_INF/SUP (_Y/Z), KT, PHI_X /Y/Z_ INF/SUP are not filled in;
for all cases: if the value of the coating is greater than the thickness/height/width of the structural element.
As well as the following specific cases:
if* FERR_MIN = “OUI “** and the keywords RHO_LONGI_MIN and RHO_TRSNV_MIN are not filled in.
if* FERR_SYME = “OUI “** and the keyword SEUIL_SYME is not filled in.
3.6.2. Alarms issued during the calculation of steels#
The calculation of bending steels can emit one or more alarms in the following cases:
if the “1D” element or at least one facet of the “2D” element is in pivot B too compressed, with* FERR_COMP = “NON “**: in this case the reinforcement density is set to -1 for the element (and the calculation on the other facets of the” 2D “element is ignored)
if the “1D” element or at least one facet of the “2D” element is in pivot C too compressed with* FERR_COMP = “NON “**: in this case the reinforcement density is set to -1 for the element (and the calculation on the other facets of the” 2D “element is ignored)
if* FERR_SYME = “OUI “and the algorithm does not succeed in determining a symmetric reinforcement for the” 1D “element (or for at least one facet of the” 2D “element) that respects the tolerance threshold specified in the keyword SEUIL_SYME ****: in this case the reinforcement density is set to -1 for the element
if the*”1D”** element is subjected to deviated bending, and if the iterative dimensioning algorithm by checking the Bresler inequality fails to converge: in this case the reinforcement density is set to -1 for the element
if* TYPE_COMB = “ELS_QP “** and the iterative sizing algorithm based on the verification of the crack opening inequality fails to converge: in this case the reinforcement density is set to -1 for the element