National Crane Published 5-27-2018 Control # 039-06 9-9
800D INSTALLATION
SECTION MODULUS TABLES
The following tables will determine the section modulus of
the truck frame. Always measure the truck frame and check
the tables to be sure that any truck factory listed section
modulus is correct.
1. Channel (Table A). Table A provides the section
modulus of channel frames in thicknesses of 3/16 in
(4.76 mm), 1/4 in (6.35 mm), 5/16 in (7.94 mm), and 3/8
in (9.52 mm) with each grouping a flange width and web
depth column. When the depth of frame channel and
flange width is known, the point at which these two lines
intersect is the section modulus from that particular
channel.
If the section modulus of the channel does not meet the
requirements, the channel should be reinforced in the
most applicable method following.
2. Channel Reinforcement (Table A). In order to provide
more strength, a channel of suitable thickness can be
added to the existing frame. The depth and flange width
of this channel should be chosen so it fits over the
existing frame. The section modulus of the needed
channel is obtained from Table A and should be added
to the section modulus obtained from the truck frame.
3. Angle Reinforcement (Table B). If the truck is
reinforced with an angle, refer to Table B for the data on
the added strength provided by the angle. Add this to the
section modulus of the channel obtained from Table A.
4. Fish Plate Reinforcement (Table C). The frame can be
strengthened by adding a fish plate of suitable thickness
and depth equal to the frame. The section modulus of
the fish plate can be obtained from Table C and this must
be added to the section modulus of the frame to obtain
the total section modulus.
5. Angle Under Reinforcement (Table D). This table lists
the section modulus of an angle with the flange under
the truck frame that is added to a frame with an angle
reinforcement already added. Add the section modulus
from Table D to the section modulus obtained from
tables A and B to determine total section modulus.
The edges of the reinforcing angles or channels are to be
flush with the edges of the frame.
Welding. Two rows of 1 in (25.4 mm) diameter plug welds
are to be placed in a staggered pattern of the web; the rows
to be spaced 5 in (127 mm) apart with welds at an interval of
4 in (102 mm). Do not weld on the flanges.
Where thickness, depth or flange width vary, interpolation
between tables or variables within a given table will provide
the strength for the section.
If you have any questions concerning frame strength or
reinforcing, contact National Crane before proceeding.
TABLE A
Section Modulus in
3
(cm
3
)
THICKNESS 3/16 in (4.76 mm) THICKNESS 1/4 in (6.35 mm)
2½ (64) 3 (76) 3½ (89) 4 (102) 2½ (64) 3 (76) 3½ (89) 4 (102)
8 (203)
9 (229)
10 (254)
11 (279)
12 (305)
13 (330)
14 (356)
15 (381)
5.3 (87)
6.3 (103)
7.3 (120)
8.4 (138)
9.5 (156)
10.8 (177)
12.0 (197)
13.4 (220)
6.0 (98)
7.1 (116)
8.2 (134)
9.4 (154)
10.6 (174)
11.9 (195)
13.3 (218)
14.7 (241)
6.7 (110)
7.9 (130)
9.1 (149)
10.4 (170)
11.7 (192)
13.1 (215)
14.6 (239)
16.1 (264)
7.5 (123)
8.7 (143)
10.0 (164)
11.4 (187)
12.8 (210)
14.3 (234)
15.9 (261)
17.5 (287)
8 (203)
9 (229)
10 (254)
11 (279)
12 (305)
13 (330)
14 (356)
15 (381)
6.9 (113)
8.2 (134)
9.5 (156)
11.0 (180)
12.5 (205)
14.1 (231)
15.8 (259)
17.5 (287)
7.8 (128)
9.2 (151)
10.7 (175)
12.3 (202)
13.9 (228)
15.6 (256)
17.5 (287)
19.3 (316)
8.8 (144)
10.3 (169)
11.9 (195)
13.6 (223)
15.3 (251)
17.2 (282)
19.1 (313)
21.2 (348)
9.7 (159)
11.4 (187)
13.1 (215)
14.9 (244)
16.8 (275)
18.8 (3.8)
20.8 (341)
23.0 (377)
THICKNESS 5/16 in (7.94 mm) THICKNESS 3/8 in (9.52 mm)
Fo
r
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