Analysis and modelling of the seismic behaviour of high ... - Ingegneria

5. SEISMIC BEHAVIOUR OF RC COLUMNS EMBEDDING STEEL PROFILES
with:
204
bc
αω wd ≥ 30µ φν
dε sy , d − 0, 035
( 5.36 )
b
0
α global confinement effectiveness factor, equal to α= αn × αs with,
for rectangular cross sections:
ωwd
2
bi
α n = 1 − ( 5.37 )
6b
h
1 − s
2b0
α s =
1 − s
2h
0
0 0
( 5.38 )
mechanical volumetric ratio of confining hoops within the critical
regions equal to:
µφ
Volume of the confining hoops f
Volume of concrete core f
yd , w
⋅ ( 5.39 )
required value of the curvature ductility factor equal to:
2q −1 if T ≥ T
T
1+ 2( q − 1) c if T1 < T
T
1
νd normalized design axial force, equal to Ed
εsy,d
bc
b0
h0
1
c
cd
N
A f
design value of tension steel strain at yield
gross cross-sectional width
c cd
width of confined core (to the centerline of the hoops)
depth of confined core (to the centerline of the hoops)
for the critical regions of columns lcr, except as specified follows:
( 5.40 )
1. If beams frame into all four sides of the joint and their width is at least
three-quarter of the parallel cross-sectional dimension of the column, the
spacing of the horizontal confinement reinforcement in the joint may be
increased to twice that required, but not to exceed 150 mm.