Overall Conceptual Seismic Design and Local Seismic Capacity Design for Components of Bridges - Structural Seismic Design Optimization and Earthquake Engineering - page 287

Figure 14. Schematic diagram of cable sliding friction aseismic bearing

to other isolation bearings, this bearing has the
advantages of simplicity in principle, wide ap-
plication, mature technique, stable performance
and low cost (Yuan, Cao, Cheung, Wang & Rong,
2010).

the superstructure and the pier should be
restrained by the cables.

Design Parameters

Depending on the above performance objects,
some important design parameters, such as the
characteristics of the cables, the shear strength of
the bolt and the integral stiffness of the bearing
should be studied carefully as follows, except for
the available characteristics of the pot bearing
from the manufacturers.

Performance Criteria

Based on the above design strategies, three perfor-
mance objectives are proposed for a cable sliding
friction aseismic bearing as follows.

1. If the expected deformation of the bearing
is less than the design free displacement,
the cables should not be mobilized and the
new bearing functions as a conventional pot
bearing.
2. Under minor and moderate earthquakes, the
shear bolt in a fixed-type bearing should
not break so that the bearing keeps service
and need not be replaced. With respect to
a sliding-type bearing, the friction capaci-
ties between the stainless steel plate and
the Teflon plate should bear the horizontal
ground motions and dissipate the seismic
energy.
3. Under severe earthquakes with the breaking
of the shear bolt, the bearing should function
as a frictional bearing to mitigate the seismic
forces and dissipate the seismic energy, while
excessive relative displacement between

1. Characteristics of the cables

According to the geometry dimensions of the
bearing, each cable's length L can be calculated
as Eq. (1), where L xy is the projective distance of
the cable in horizontal plane, H is the bearing
total height, A and B are length and width of the
upper plate, C and D are length and width of the
lower plate, δ x and δ y are the design displacement
in the bearing's longitudinal and transverse direc-
tion.

2 2

L = [ δ + − ( A C ) / ] 2 + [ δ + ( B D − ) / ] 2

xy x y

L = H

2

+ L

2

xy

(1)