DESIGN SPECIFICATIONS FOR HIGHWAY BRIDGES - IISEE

M
u
y
y0
・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (10.3.4)
M
y0
where
δy0 : Horizontal displacement at the time of yielding of axial tensile reinforcing bars
at the outermost edge of the pier bottom section (called “initial yield
displacement” hereafter) (mm)
Mu : Ultimate bending moment at the pier bottom section (N· mm)
My0: Bending moment at the time of yielding of axial tensile reinforcing bars at the
outermost edge of the pier bottom section (N· mm)
H : Distance from the pier bottom to the height of superstructural inertial force
(mm)
(7) Ultimate limit state denotes the state when concrete strain at the location of axial
compressive reinforcement reaches the ultimate strain. With consideration of
plastic hinges occurring at the damaged sections, the lateral strength and the
ultimate displacement shall be calculated by Equations (10.3.5) and (10.3.6),
respectively.
M
u
Pu ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (10.3.5)
h
δ u =δ y + (φ u -φ y ) L p ( h-L p / 2 ) ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (10.3.6)
where
Lp: Plastic hinge length (mm) calculated by Equation (10.3.7)
L p = 0.2h – 0.1 D ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・ (10.3.7)
in which 0.1D ≦ Lp ≦0.5D
D : Sectional depth (mm) (D shall be the diameter of a circular section, or the length
of a rectangular section in the analytical direction)
φy: Yield curvature at the pier bottom section (1/mm)
φu : Ultimate curvature at the pier bottom section (1/mm)
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