National Crane 600H, Service Manual

Page: 195 / 232

NATIONAL CRANE
08-19-2022 Control # 092-13
9-13
600H SERVICE CRANE INSTALLATION
9
EXAMPLE
A truck frame of 110,000 psi (758 MPa) yield strength steel has the following dimensions: 3/8 in.
(9.65 mm) thick, 3 in. (76.2 mm) flanges and is 10.25 in. (260 mm) deep. To find the frame
section modulus:
1. From Table A, 3/8 in. (9.65 mm) thickness,
• W (width) = 3 in. (76.2 mm),
• D (depth) = 10 in. (254 mm)
• section modulus = 15.4 in.3 (252 cm3.
2. From Table A, 3/8 in. (9.65 mm) thickness,
• W = 3 in. (76.2 mm),
• D = 11 in. (279 mm),
• Section Modulus = 17.7 in.3 (290 cm3).
3. Interpolating between the two values:
• 10 in. (254 mm) deep channel = 15.4 in.3 (252 cm3)
• 11 in. (279 mm) deep channel = 17.7 in.3 (290 cm3)
• 10.5 in. (267 mm) deep channel
4. Now interpolate between a 10 in. (254 mm) deep channel and a 10.5 in. (267 mm) deep channel
to get the section modulus of a 10.25 in. (260 mm) deep channel.
• 10 in. (254 mm) deep channel = 15.4 in.
3
(252 cm
3
)
• 10.5 in. (267 mm) deep channel = 16.55 in.
3
(271 cm
3
)
• 10.25 in. (260 mm) deep channel
5. A 3/8 in. (9.65 mm) x 3 in. (76.2 mm) x 10.25 in. (260 mm) truck frame has a 15.98 in.
3
(262 cm
3
)
Section Modulus and RBM of 110,000 psi x 15.98 in.
3
= 1,757,800 in. lbs. (758 MPa x 262 cm
3
=
198,596 N.m)
• 10.5 in. (267 mm) deep channel = 16.55 in.
3
(271 cm
3
)
• 10.25 in. (260 mm) deep channel l
6. 15.98 in.3 (262 cm3) Section Modulus, 110,000 psi (758 MPa) steel is adequate for a standard
mount with a torsion box.
15.4 in.
3
÷ 17.7 in.
3
= 16.55 in.
3
=
2
252 cm
3
÷ 290 cm
3
271 cm
3
=
=
2
15.4 in.
3
÷ 16.55 in.
3
= 15.98 in.
3
=
2
252 cm
3
÷ 271 cm
3
262 cm
3
=
=
2
15.4 in.
3
÷ 16.55 in.
3
= 15.98 in.
3
=
2
252 cm
3
÷ 271 cm
3
262 cm
3
=
=
2
3.00
(76.2)
10.25
(260)
0.375
(9.65)
Inch
(mm)
REFERENCE ONLY