$$$$ EC8ACSIS NOTICE CHAT 11/09/12 21:15:58 7124
DATE 11/09/12
Procedure EC8ACSIS Voir aussi :
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RS = EC8ACSIS TAB1;
Description :
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a)
Generation of a spectrum of response RS (EVOLUTION type object
composed of a single curve) according to EUROCODE instructions
number 8 and TAB1 parameters (TABLE type object).
EUROCODE 8 suggests an evolution with the following period :
0 < T < T1 Be = 1 + T/T1 * (B0-1)
T1 < T < T2 Be = B0
T2 < T Be = (T2/T)**K * B0
Be(B0) being the spectrum of standard acceleration response,
for a 5% damping, RS can be obtained by inputting the soil
maximum acceleration Ag and Khi damping value (<.7) :
RE = Ag * Be(nu*B0) nu=(.05/Khi) **.5
The code must be completed for high periods. For standard grounds
the displacement is limited :
d < dmax = (Ag/g) * D0
in which g is the gravity acceleration.
In this case, RE will be defined by dmax multiplied by the
amplification factor for high periods AMPF (AMPF =1.4).
Series of data (T1,T2,B0,K and D0) are allowed for grounds of
A, B or C type.
The spectrum RS is generated on a grid of period ranging
between TINI (T2).
b)
Generation of a spectrum of response RS for using all the linear
analyses. In this case, B0 is divided by the behavior factor
B0 = B0 / Q
and by T > T2, the condition of constant displacement is not
imposed i.e.
RE = Ag * Be(Eta*B0/Q)
condition on RE :
RE >= 0.2 Ag
compulsory parameters :
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The parameters are contained in TAB1 (TABLE type object).
index pointed object comments
type
TYPE MOT indicating the type of spectrum i.e.
a) 'GSIG' (spectrum of response for the
generation of artificial signals)
b) 'ALIN' (spectrum of response for linear
analysis (linear analysis design spectra)).
In this case, supplying the behavior factor
Q in the table is compulsory
Q FLOTTANT indicating the value of the behavior
coefficient if TYPE equals 'ALIN'.
AG FLOTTANT indicating Ag (cm/s/s).
SOIL MOT indicating the type of ground
'A' 'B' or 'C'
ou
T1
T2 FLOTTANT indicating T1, T2 and B0.
B0
TINI
TFIN FLOTTANT giving TINI and TFIN.
optional parameters :
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The parameters are contained in TAB1 (TABLE type object).
index pointed object comments
type
K FLOTTANT referring to K (default = 1
leading to a constant velocity)
D0 FLOTTANT referring to D0
(default = no limitation).
AMOR FLOTTANT referring to Khi (default = 0.05)
GRAN MOT referring to the response physical
magnitude: 'A'(cceleration), 'V'(itesse)
(velocity) or'D'(eplacement relatif)
(relative displacement).
The default is 'A'.
ABSC MOT referring to the abscissa physical
magnitude: 'PERI'(ode) (period) or
'FREQ'(uence) (frequency).
The default is 'PERI'.
N ENTIER referring to the number of points on the
NP' ENTIER spectrum branches beyond T2
(default = 25).