A. The purpose of
this section is to emphasize that the ground under the ABS pads must be
leveled, evenly compacted, and cleared of all vegetation and debris before the
placement of the pad and all pads are to be installed flat side down, ribbed
side up.
B. Note that if
the pad deflects more than 5/8 of an inch when installed, pier spacing is
incorrect for the existing soil conditions. The maximum deflection in a single
pad is 5/8 of an inch measured from the highest point to the lowest point of
the top.
C. Installation
Instructions for ABS Pads B 26X 26 Inch Pad Configuration:
1. All pads are to be installed flat side
down, ribbed side up.
2. The
ground under the pads should be leveled as smooth as possible with all
vegetation removed. Pads are not to be placed on natural grade unless otherwise
permitted by the local building authority.
3. Pier and pad spacing will be determined by
the Factory-Built home manufacturer's written set up instructions. In the
absences of home manufacturer's written set up instructions and written set up
instructions from the pad manufacturer, the pier and pad spacing shall be no
greater than 6 ft. apart for Wind Zone I areas and no greater than 4 ft. for
Wind Zone II areas.
4. The open
cells between the ribbings on the upper side of the pads may be filled with
soil or sand after installation to prevent any accumulation of stagnant water
in the pads.
5. A pocket
penetrometer may be used to determine the actual soil bearing value. If soil
testing equipment is not available, as mentioned earlier in the Regulation that
an assumed soil bearing capacity value of 1000 lbs./square foot (psf) may be
used.
6. All pad sizes shown are
nominal dimensions and may vary to 1/8 of an inch.
7. The maximum deflection in a single pad is
5/8 of an inch measured from the highest point to the lowest point of the top
face. (Please review Table V and Figures 6 and 7).
TABLE V - SIZE AND LOAD
|
PAD SIZE
|
PAD AREA
|
1000 LB.SOIL
|
2000 LB.SOIL
|
3000 LB.SOIL
|
|
16" X 16"
|
256 sq. in.
|
1,780 lbs.
|
3,560 lbs.
|
5,333 lbs.
|
|
18.5" X 18.5"
|
342 sq. in.
|
2,375 lbs.
|
4,750 lbs.
|
7,125 lbs.
|
|
20" X 20"
|
400 sq. in.
|
2,750 lbs.
|
5,500 lbs.
|
8,250 lbs.
|
a. Any
configuration above may be used to replace a home manufacturer's recommended
concrete or wood base pad.
b. The
maximum load at any intermediate solid value may be determined as the average
of the next lower and next higher soil values given in the above table.
c. Pad sizes shown are nominal
dimensions and may vary up to 1/8 inch.
d. Pad loads are the same when using single
stack or double stack blocks.
Click
Here To View Image
Figure 6. ABS pad assembly installation instructions
for a 26"x 26" configuration
Click
Here To View Image
Figure 7. Maximum allowable deflection in a single
ABS pad
