r - The Hong Kong Polytechnic University

e formed at the column base and the ductility demand of the column can be reduced. In addition, results also
shows that if the footing uplift took place, there was a decrease in plastic deformation at the plastic hinge of a
column as a result of the energy dissipation of the inelastic rocking mechanism. The extent of decrease in plastic
deformation depends on the ratio of the moment capacity of column to the limit value of moment that
corresponds to the base moment limitation sustained by the foundation.
200
drift (%)
-8 -6 -4 -2 0 2 4 6 8
200
drift (%)
-8 -6 -4 -2 0 2 4 6 8
200
drift (%)
-8 -6 -4 -2 0 2 4 6 8
Lateral force (kN)
100
0
-100
CD30FB-F
Lateral force (kN)
100
0
-100
CD30FB-R
Lateral force (kN)
100
0
-100
CD30FS-R
Moment (kN-m)
-200
-200 -100 0 100 200
lateral displacement (mm)
500
400
300
200
100
0
-100
-200
-300
-400
-500
CD30FB-F
-0.08-0.06-0.04-0.02 0 0.02 0.04 0.06 0.08
Rotation (radian)
Moment (kN-m)
-200
-200 -100 0 100 200
lateral displacement (mm)
-200
(a) Lateral force-displacement curves
500
400
300
200
100
0
-100
-200
-300
-400
-500
CD30FB-R
-0.08-0.06-0.04-0.02 0 0.02 0.04 0.06 0.08
Rotation (radian)
Moment (kN-m)
500
400
300
200
100
0
-100
-200
-300
-400
-500
-200 -100 0 100 200
lateral displacement (mm)
CD30FS-R
-0.08-0.06-0.04-0.02 0 0.02 0.04 0.06 0.08
Rotation (radian)
(b) Moment-rotation curves
Figure 6 Experimental results for the cyclic loading test of specimens CD30xx-x
ON-SITE EXPIRIMENT AT NIUDOU BRIDGE
Background and Objectives
Earthquakes and floods are the most dangerous threats to bridges in Taiwan. Earthquakes exert force on bridges
and floods undermine their foundations; both can severely damage bridges and greatly shorten bridges' lives.
Due to laboratory space restrictions, past engineering research almost never conducted experiments
simultaneously involving bridge structures and bridge foundations, and compared the results with modern
design theory. Since the Old Niudou Bridge was scheduled for demolition, the old bridge provided a very
suitable experimental subject for investigation of current design theory. Therefore, an on-site experiment at
Niudou bridge was performed last year by NCREE. The research team felt that the experiment would certainly
attract the interest of persons worldwide engaged in bridge research, and expected that the experiment could
provide valuable experimental data and models concerning bridges' interaction with soil structure, as well as the
mechanisms of earthquake damage and foundation erosion, enabling a better understanding of bridge earthquake
resistance.
LVDT
Tilt meter
Figure 7 Locations of jacks; use of a wall-type bridge pier as a reaction wall
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