DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

6.3.3 Design Horizontal Seismic Coefficient
(1) Design horizontal seismic coefficient for Level 1 Earthquake Ground Motion shall
be calculated by Equation (6.3.1). When the kh-value obtained by this Equation is
less than 0.1, kh shall be taken as 0.1
k c k ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (6.3.1)
h
Z
h0
where
k h : Design horizontal seismic coefficient (rounded to two decimals)
k h0 : Standard value of the design horizontal seismic coefficient for Level 1
Earthquake Ground Motion, shown in Table 6.3.1 below.
c z : Modification factor for zones specified in Section 4.4
In verifying seismic performance for Level 1 Earthquake Ground Motion, inertia force
caused by the soil weight and seismic earth pressure shall be calculated using design
horizontal seismic coefficient at ground level obtained by Equation (6.3.2)
k c k ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (6.3.2)
hg
Z
hg 0
where
k hg : Design horizontal seismic coefficient at ground level (rounded to two
decimals)
k hg0 : Standard value of the design horizontal seismic coefficient at ground level for
Level 1 Earthquake Ground Motion. Values of 0.16, 0.2 and 0.24 shall be used
for ground types I, II and III, respectively.
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