CRANE INSTALLATION NBT30H-2 SERVICE MANUAL
9-8 03-20-2019 Control # 613-06
The following tables 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 9-9) - Table A provides the
section modulus of channel frames in thicknesses of
4.76 mm (0.19 in), 6.35 mm (0.25 in), 7.94 mm (0.31 in),
and 9.52 mm (0.38 in) 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) - 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 9-10) - 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 9-10) - 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 9-11) - 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 25.4 mm (1 in) diameter plug welds
are to be placed in a staggered pattern of the web; the rows
304
(120)
274
(108)
243
(96)
213
(84)
182
(72)
152
(60)
121
(48)
91
(36)
61
(24)
30
(12)
0
(0)
FIGURE 9-6
NOTE: All dimensions are centimeters (inches)
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