DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

Chapter 11 Verification of Seismic Perormance of Steel Colums
11.1 General
(1) Allowable values such as allowable displacements of a steel pier for Seismic
Performance Level 2 or Level 3, and inelastic hysteretic models in a dynamic
analysis shall be determined in accordance with the provisions in Section 11.2.
(2) A steel pier shall be designed in such a manner that a ductile failure can be
prevented, and the required ductility can be ensured. A steel pier designed in
accordance with the structural details specified in Section 11.3 can be regarded as a
satisfactory one.
(3) An anchorage block between a steel pier and an Reinforced Concretefoundation
shall be designed for the Level 2 Earthquake Ground Motion without causing the
plastic deformation at the anchorage. An anchorage designed in accordance with
the provisions specified in Section 11.4 can be regarded as satisfactory.
11.2 Verification of Seismic Performance by Dynamic Analysis
(1) The Seismic Performance Level 2 or Level 3 shall be verified in accordance with the
following provisions.
1) In verification of Seismic Performance Level 2, the maximum response of a
steel pier obtained from a dynamic analysis shall not exceed its allowable value.
In addition, the residual displacement calculated by substituting the maximum
response displacement at the height of the point of the superstructural inertia
force into Equation (6.4.9), shall not exceed the allowable residual
displacement. Ratio (r) of the secondary post-yielding stiffness to the yielding
stiffness used in calculation of the residual displacement in Equation (6.4.9),
and residual displacement modification factor (CR) shall be taken as the values
defined in Table 11.2.1.
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