Stochastic modeling of deterioration in buildings and civil infrastructure - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 413

gives the basic geometric and material properties for the example RC
column. The column is designed to have properties typical of a bridge
designed following Caltrans Seismic Design Specifi cations (Caltrans, 2006).
In the table, in addition to the quantities already defi ned, D g is the diameter
of the column, f

c is the compressive strength of concrete, f y is the yield
strength of reinforcing steel (same for longitudinal and transverse), f su is the
ultimate strength of steel,

′

l is the ratio of the area of longitudinal steel to
the gross cross-sectional area of the column,

ρ

ρ s is the volumetric ratio of
confi nement steel, and P u is the axial load on the column. Table 16.2 shows
the global structural properties for the bent computed using the pushover
curve shown in Fig. 16.3, where V is the lateral force,

is the lateral dis-
placement of the column top, K is the pre-yield stiffness, V y is the shear
force at yield,

Δ

Δ

y is the displacement at yield, M

= P u / g and T = 2 π K

N

Table 16.2 Global structural properties of the RC bridge bent

Property Value Units

T N 0.71 s

Δ y / H 0.01 -

V y / Mg 0.30 -

M 151.6E03 kg

100

V y

80

60

K

40

20

Pushover curve

Bilinear fit

0

0 0.01 0.02 0.03 0.04 0.05

Δ y / H Δ / H

16.3 Pushover curve for the bent column.