Sanyo ECO G SGP-EW120M2G2W, Technical Data Manual

Page: 63 / 115

System Design
7. Center-of-gravity and earthquake resistance
D-32
In the diagram above,
G : Position of center-of-gravity of equipment F
H
: Design horizontal force (N)
W : Weight (N) of equipment alone (F
H
=K
H
・
W)
R
b
: Pull-out force of one mounting bolt (N) F
V
: Design vertical force (N)
n : Total no. of mounting bolts
n
t
: No. of mounting bolts on one side subject to tension F
V
= F
H
by toppling force (in the direction being considered)
h
G
: Height of unit center-of-gravity above mounting A : Nominal cross-sectional area of one
surface (mm) mounting bolt (mm
2)
L : Bold span (mm) from direction of concern
(L
1
: End-on direction, L
2
= Broadside direction)
L
G
: Distance from center-of-bolt to center-of-gravity as τ : Shear stress on bolt (N/ mm
2
)
viewed from direction of concern (but L
G
≤
/2 (mm)) f
ts
: Allowable tensile stress on a bolt with
simultaneous shear stress (N/ mm
2
)
However, f
ts
≤
ft
Mounting bolt pull-out force Mounting bolt tensile stress
R
b
= δ =
Mounting bolt shear stress Allowable tensile stress on a bolt with
simultaneous shear stress
τ = f
ts
= 1.4f
t
- 1.6 τ
Table of allowable stress on bolts Units (N/ mm
2
)
Long-term allowable stress Short-term allowable stress
Bolt
material
Bolt diameter
Tension (f
t
) Shear (f
s
) Tension (f
t
) Shear (f
s
)
40 mm or less 118 88 176 132
SS400
More than 40 mm 108 80 162 121
40 mm or less 137 103 206 154
SUS304
More than 40 mm 126 94 188 141
Notes
1) The values in the above table are derived from “Steel structure design criteria” published by the
Architects Institute of Japan.
2) Use the value f
t
in the table if necessary to investigate bolt tensile stress.
3) Strength of a bolt subject to simultaneous tension and shear can be checked as follows.
a)
τ
f
s
b)
σ
≤
the smaller of f
t
or f
ts
, but f
ts
= 1.4f
t
– 1.6
τ
where,
τ
: Shear stress on bolt
σ
: Tensile stress on bolt (
σ
= R
b
/A)
f
s
: Allowable stress on bolt with shear stress only (value from above table)
f
t
: Allowable stress on bolt with tensile stress only (value from above table)
f
ts
: Allowable tensile stress on a bolt with simultaneous shear stress, but f
ts
≤
f
t
4) The allowable tensile stresses in the above table are evaluated using the cross-sectional area of the
minor diameter of the screw thread. However, when calculating for selection purposes, the
cross-sectional area based upon the nominal diameter may be used.
5) If the threaded portion is subject to shear, then if using the cross-sectional area based upon the nominal
diameter, multiply the value of f
s
in the above table by 0.75.
F
H
・
h
G
- (W-F
V
)
・
L
G
L
・
n t
R
b
A
F
H
n
・
A
1
2