DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

c B
: Gap modification factor on natural period difference. c B
takes the values from
Table 14.4.1, depending on the natural period difference ΔT of the two
adjacent girders.
14.4.3 Joint Protectors
(1) A joint protector capable of protecting the expansion joints against Level 1
Earthquake Ground Motion shall be designed. Also, it shall be set up in such a way
that it does not interfere with the functions of the bearing supports and the
expansion joints.
(2) Design seismic forces in designing a joint protector shall generally be calculated
from Equation (14.4.3). The stresses occurring in the joint protector due to the
design seismic force shall not be greater than 1.5 times the allowable value.
HJ = kh Rd ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・(14.4.3)
where
HJ : Design seismic force of the joint protector (kN)
kh : Design horizontal seismic coefficient of Level 1 Earthquake Ground Motion
specified in Subsection 6.3.3
Rd : Dead load reaction (kN)
(3) The gap between adjacent decks of a joint protector in the longitudinal direction to
the bridge axis shall not be less than its design value specified in Subsection 4.2.2
of Part I Common Provisions and also not exceeding the allowable expansion length
of the expansion joint.
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