DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

(16) Plastic hinge
A specific portion of an Reinforced Concrete structural member capable of
performing ductile behavior when subjected to repeated alternate deformations.
In the calculation of ultimate horizontal displacement, a length of an estimated
plastic hinge in the axial direction of the member is defined as the plastic hinge
length, and sections in the plastic hinge length is defined as the plastic hinge
zone.
(17) Horizontal inertia force distributed structure
Structure supporting a superstructure with a plural number of substructures, for
the purpose of distributing the seismic inertia forces to these substructures. The
structure includes a bridge with elastic supports such as rubber bearings and
isolation bearings, and a bridge with plural fixed supports.
(18) Seismiclly-Isolated bridges
Bridge with isolation bearings intended to make natural period of the bridge
longer and to increase the damping characteristics to decrease the inertia forces
during an earthquake.
(19) Unseating prevention system
Structural system having a seat length, an unseating prevention structure, an
excessive displacement stopper, and a structure for protecting the superstructure
from subsidence, in order to prevent a superstructure from unseating due to an
earthquake.
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