Assessing the seismic vulnerability of masonry buildings - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 340

Ω eff

T u

h i

G

H eff

T u

H

h o

T i

A eff

I eff

T b

13.3 Schematics of the meanings of the parameters used in the
calculation of the effective stiffness and effective mass for the
equivalent degree of freedom and in equations (13.2) to (13.4).

where, with reference to Fig. 13.3, H eff is the height of the portion involved
in the mechanism; E t is the estimated elastic modulus of the masonry as it
can be obtained from experimental literature for different masonry typolo-
gies; I eff and A eff are the second moment of area and the cross-sectional area,
respectively, calculated by taking into account extent and position of open-
ings and variation of thickness over height; k 1 and k 2 are constants which
assume different values depending on edge constraints and whether shear
and fl exural stiffness are relevant for the specifi c mechanism.
The effective mass Ω eff is calculated by following the same approach and

it includes the portion of the elevation activated by the mechanisms plus
the mass of the horizontal structures involved in the mechanism (shown in