US2020308832A1PendingUtilityA1
Method of designing rolled h-section steel, rolled h-section steel, and method of manufacturing rolled h-section steel
Est. expiryFeb 17, 2037(~10.6 yrs left)· nominal 20-yr term from priority
E04C 2003/0452E04C 3/06
43
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Claims
Abstract
A method of designing a rolled H-section steel includes: setting a height dimension H from an upper flange to a lower flange, a width dimension W of each of the upper flange and the lower flange, a plate thickness tw of a web, and a plate thickness tf of each of the upper flange and the lower flange so that, when it is assumed that a value obtained by dividing a second moment of area Ix about a strong axis by an outer circumferential length Lp in a cross-sectional shape when viewed in a cross section perpendicular to a member axis direction is a surface treatment economy Ix/Lp and an area of the cross-sectional shape is S, a predetermined relational formula is satisfied.
Claims
exact text as granted — not AI-modified1 . A method of designing a rolled H-section steel,
the rolled H-section steel including
an upper flange,
a lower flange, and
a web connecting the upper flange to the lower flange,
an outer circumferential surface of each of the upper flange, the lower flange, and the web being subjected to a surface treatment, the method comprising: setting a height dimension H from the upper flange to the lower flange, a width dimension W of each of the upper flange and the lower flange, a plate thickness tw of the web, and a plate thickness tf of each of the upper flange and the lower flange so that, when it is assumed that a value obtained by dividing a second moment of area Ix about a strong axis by an outer circumferential length Lp in a cross-sectional shape when viewed in a cross section perpendicular to a member axis direction is a surface treatment economy Ix/Lp and an area of the cross-sectional shape is S, Formulas (35) to (38) are satisfied, the height dimension H is 700 mm or more and 1500 mm or less, the width dimension W is ⅕ or more and ½ or less of the height dimension H, the plate thickness tw is 9 mm or more and 32 mm or less, and the plate thickness tf is 12 mm or more and 40 mm or less
[Math 28]
Ix/Lp=C k1 ·exp( C k2 ·H/S ) (35)
C k1 =120+100· k (36)
C k2 =−106+10· k (37)
6.1≤ k≤ 8 (38)
2 . The method of designing a rolled H-section steel according to claim 1 ,
wherein, under a condition that the rolled H-section steel is used as a beam extending in the member axis direction and both end portions of the rolled H-section steel in the member axis direction are fixed, a condition that lateral movement of the rolled H-section steel in a width direction in a middle portion in the member axis direction is restricted, and a condition in which an intermediate load acts on the upper flange from above and end loads act on both end portions in the member axis direction, using an elastic lateral buckling moment M cr of the beam calculated from Formulas (12) to (16), the height dimension H, the width dimension W, the plate thickness tw, and the plate thickness tf are set so that lateral buckling does not occur in the beam, wherein, V cr : a shear force acting on the end portions of the beam in the member axis direction, W cr : the intermediate load acting on the middle portion of the beam in the member axis direction, β and γ: coefficients determined from Formulas (1) and (2) depending on loads V cr and W cr , l: a length of the beam in the member axis direction, E: a Young's modulus, I: a second moment of area about a weak axis of the lower flange, G: a shear elastic modulus, J: a Saint-Venant's torsion constant, d b : a plate thickness center-to-center distance between the upper flange and the lower flange, y: a length from one end portion of the beam in the member axis direction as a reference to any point of the beam in the member axis direction, θ y : a torsion angle generated in the beam due to lateral buckling, θ′ y : a first order derivative of θ y , θ″ y : a second order derivative of θ y , and a: a parameter for integration
[
Math
29
]
M
cr
=
1
(
1
-
β
-
γ
)
A
+
(
β
+
γ
)
C
+
γ
D
(
B
2
π
2
EId
b
l
2
+
A
GJ
d
b
)
(
12
)
A
=
l
∫
0
l
θ
y
′2
dy
(
13
)
B
=
l
3
2
π
2
∫
0
l
θ
y
″2
dy
(
14
)
C
=
∫
0
l
y
θ
y
′2
dy
(
15
)
D
=
2
l
∫
0
l
∫
0
y
(
y
-
a
)
θ
y
′2
dady
(
16
)
[
Math
30
]
V
cr
=
-
(
β
+
γ
)
M
cr
l
(
1
)
∫
0
l
W
cr
ydy
=
γ
M
cr
(
2
)
3 . The method of designing a rolled H-section steel according to claim 2 ,
wherein the height dimension H, the width dimension W, the plate thickness tw, and the plate thickness tf are set so that a square root of a value obtained by dividing a full plastic moment Mp of the rolled H-section steel by the elastic lateral buckling moment M cr becomes 0.6 or less.
4 . A rolled H-section steel comprising:
an upper flange; a lower flange; and a web which connects the upper flange to the lower flange, wherein an outer circumferential surface of each of the upper flange, the lower flange, and the web is subjected to a surface treatment, a height dimension H from the upper flange to the lower flange is 700 mm or more and 1500 mm or less, a width dimension W of each of the upper flange and the lower flange is ⅕ or more and ½ or less of the height dimension H, a plate thickness tw of the web is 9 mm or more and 32 mm or less, a plate thickness tf of each of the upper flange and the lower flange is 12 mm or more and 40 mm or less, and when it is assumed that a value obtained by dividing a second moment of area Ix about a strong axis by an outer circumferential length Lp in a cross-sectional shape when viewed in a cross section perpendicular to a member axis direction is a surface treatment economy Ix/Lp and an area of the cross-sectional shape is S, the height dimension H, the width dimension W, the plate thickness tw, and the plate thickness tf satisfy Formulas (35) to (38)
[Math 31]
Ix/Lp=C k1 ·exp( Ck 2 ·H/S ) (35)
C k1 =120+100· k (36)
Ck 2 =−106+10· k (37)
6.1≤ k≤ 8 (38)
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