DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

2) Seismic hydrodynamic pressure acting on a column structure completely
surrounded by water:
Resulting force of seismic hydrodynamic pressure acting on a column structure
completely surrounded by water and the height of the resultant force shall be
calculated by Equations (6.2.8) and (6.2.9), respectively. (Refer to Fig. 6.2.2).
when h
b ≦2.0
3 b
b
P k
hw0
A0h
1
4 a 4h
b
when 2.0< ≦4.0 h
3 b b
P k
hw
A0
h 0.7
4 a 10h
b
when 4.0< h
0 ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (6.2.8)
9 b
P k
hw0
A0h
40 a
3
h g
7 h ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (6.2.9)
where
P : Resultant force of seismic hydrodynamic pressure acting on a structure (kN)
kh: Design lateral seismic coefficient for Level 1 Earthquake Ground Motion
specified in Section 6.3.3
w0: Unit weight of water (kN/m 3 )
h : Water depth (m)
hg: Height from the ground surface to the resultant force of hydrodynamic pressure
(m)
b: Structural width in the direction perpendicular to the direction of hydrodynamic
pressure (m)
a : Structural width in the direction of hydrodynamic pressure (m)
A0: Sectional area of the substructure (m 2 )
19