CRANE INSTALLATION NBT40 SERVICE MANUAL
9-14 Published 8-01-2017 Control # 287-11
The following tables (A,B,C,D) determine the section
modulus of the truck frame. Measure the truck frame and
check the tables to be sure that the truck factory listed
section modulus is correct.
• Channel (Table A page 15) - Table A provides the
section modulus of channel frames in thicknesses of
3/16" (4.76 mm), 1/4" (6.35 mm), 5/16" (7.94 mm), and
3/8" (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.
• Channel Reinforcement (Table A page 15) - 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. Add this to the
section modulus of the channel obtained from Table A.
• Angle Reinforcement (Table B page 16) - 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.
• Fish Plate Reinforcement (Table C page 16) - 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.
• Angle Under Reinforcement (Table D page 16) - 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" (25.4 mm) diameter plug welds are
to be placed in a staggered pattern of the web; the rows to be
spaced 5" (127 mm) apart with welds at an interval of 4"
(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.
120
(304)
108
(274)
96
(243)
84
(213)
72
(182)
60
(152)
48
(121)
36
(91)
24
(61)
12
(30)
0
(0)
FIGURE 9-10
NOTE: All dimensions are inches (centimeters)
Distance From SFO Attachment
Inches (centimeters)
Reference Only
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