Page 266 - Numerical Analysis and Modelling in Geomechanics

F.PERGALANI, V.PETRINI, A.PUGLIESE AND T.SANÒ 247

Table 8.3 Classifying table for qualitative local effect situations (Pergalani et al., 1999)

Table 8.4 Reference coefficient Fb of each reference seismic input for normal ductility
structures (Pergalani et al., 1999)

(8.14)

is the amplification coefficient which states the relation between seismic hazard
for reference site conditions (rock or stiff soil) and the seismic protection level
imposed by the Italian seismic code, for the second category zone, in absence of
site amplifications;

(8.15)

is the amplification coefficient, accounting for both site effects and seismic
hazard variability.
To derive SI (code) a set of assumptions is needed, as the Italian seismic code
only gives the design spectrum. In particular two factors should be considered:
the ratio between the allowable stresses and the yield stresses, α, and the
behaviour factor, q. For the former an average value of 2 can be assumed
according to the Italian code, while for the latter the value may vary in the range
3–6 for typical buildings.
If the value 2 is assumed for the first factor and the value 4.5 for the behaviour
factor, the resulting Fb values are given in Table 8.4.