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seismic performance is directly correlated with
the cable stiffness for the floating cable-stayed
bridge installed with them.
The SCC bridge combines the mechanical
advantages of steel and concrete, making the
bridge more reasonable and durable. Since 1950s,
much research has been carried out to promote
the development of SCC bridges. Many countries
such as USA and Japan developed the design
guidelines and specifications (Brozzetti, 2000;
Hayward, 1988). Recently, a growing concern
is mainly about the seismic performance of this
kind of bridges during earthquakes. So a typical
SCC continuous girder bridge and an SCC arch
bridge are mainly studied to discuss the seismic
potential and performance of SCC bridges.
Since the seismic mitigation and isolation de-
sign has received growing attention and become
a major research topic, various isolation devices
including rubber bearings, frictional bearings and
roller bearings have been developed for bridges
(Kunde & Jangid, 2003). Pot bearings are widely
used in long span railway and highway bridges for
their higher vertical load bearing capacities and
better deformation ability. It can be assigned to be
fixed or frictional in horizontal directions depend-
ing on the design demands of the bridges. How-
ever, the pot bearing cannot restrain the excessive
seismic displacements when sliding, and cannot
reduce the seismic forces when fixed. Considering
the restraint measures of the pot bearing, a new
seismic isolation bearing, known as cable sliding
friction aseismic bearing is introduced. This type
of bearings can be regarded as the combination of
pot bearings and restraining cables and has both
advantages of them.
Considering the seismic vulnerability of
potential plastic hinge regions of bridge piers,
more and more bridge piers are reinforced with
SFRC in earthquake regions for its better ductil-
ity performance and energy dissipation capaci-
ties (Gao, 2009). For the simplest single-column
bridge pier, the seismic performance of the piers
globally and locally reinforced with SFRC are
studied and compared. Also current seismic de-
sign guidelines of various countries give different
proposals for estimating the plastic hinge length
of a single-column pier reinforced with SFRC
(Zhu, Fu, Wang, & Yuan, 2010). There is a need
therefore to clarify these differences to facilitate
the application of SFRC to bridge piers.
Pile group foundations are widely used in long
span cable-stayed bridges and suspension bridges.
Many post-earthquake damage investigations
and theoretical studies show that the pile group
foundations are usually vulnerable components
under earthquakes (Zhou, 2008). Generally, they
are considered to be strengthened with the steel
protective pipes (SPPs) for the construction con-
venience. But the seismic performance is still not
fully determined. Based on numerical simulations
and scale-model experiments, seismic capacities,
hysteretic behavior and energy dissipation capa-
bilities are reviewed in this chapter.
OVERALL CONCEPTUAL SEISMIC
DESIGN FOR BRIDGES
In order to decrease the seismic demands in the
conceptual design phase, the main concern of the
engineers is to make an optimal arrangement of
structural components to let the structure's dy-
namic characteristics adapt to the site conditions
and the seismic demands become more uniform
and rational along structural components. Over-
all conceptual seismic design is applicable for
the global structure design based on the linear
seismic analysis. In the following sections, four
design strategies are reviewed from the overall
conceptual seismic design viewpoint: (i) optimal
design for layout and detail of continuous girder
bridge; (ii) design of towers for long span floating
cable-stayed bridge; (iii) seismic isolation mecha-
nism of elastic cables in cable-stayed bridge; (iv)
seismic potential and performance for long span
SCC bridges.
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