Civil Engineering Reference
In-Depth Information
Figure B.49
Failures at the base of reinforced concrete bridge piers: bond failure of lap slices (
left
) and weld
failure of longitudinal reinforcement (
right
) in the 1995 Kobe (Japan) earthquake (
courtesy of
Dr. Kazuhiko
Kawashima)
Figure B.50
Shear failure within (
left
) and outside (
right
) the plastic hinge region in the San Fernando Mission
Blvd-Gothic Avenue Bridge and I-10 Freeway at Venice Blvd, respectively, during the 1994 Northridge (California)
earthquake
In particular, Figure B.50 shows a case in which fl exural and shear failure mechanisms were
combined. The reduced contribution of concrete to the shear resistance in the plastic hinge area, after
the concrete was damaged, led to shear failure.
(iii) Column Buckling and Fractures
A number of steel and composite columns suffered extensive local buckling (also known as ' elephant
foot mode') during the 1995 Kobe earthquake (Figure B.51). This failure mode occurred at the base of
piers with hollow sections infi lled with concrete; the transition zone between infi lled and unfi lled con-
crete was critical for buckling. In several cases, this coincided with the termination of concrete infi lling,
used to protect the piers from vehicle impact.
