Xylem IMCPFIBRGL R01 Fiberglass Basin - Manual (Page 5)

5
WARNING
WARNING
PLACEMENT AND COMPACTION OF
BACKFILL
Compaction of backfill materials should be adequate to
ensure the support of the tank, and to prevent movement
or settlement. Backfill materials should be placed in 12”
lifts and compacted to a minimum soil modulus of 700
pounds per square inch (psi).
SUPPORTING PIPING, EQUIPMENT AND
ACCESSORIES
Support for piping, equipment and other accessories
must be provided during backfilling. Using the basin to
support piping, equipment, cribbing, bracing, or blocking
is never permitted. During backfilling, temporary
supporting materials must be carefully installed and
removed to prevent damage to the basin, piping, or
equipment.
Using the basin to support any loading
carried or created by piping, equipment,
cribbing, bracing, or blocking is never permitted.
7: ANCHORAGE
GENERAL
When basin installations are located in areas subject
to high water tables or flooding, provisions should be
made to prevent the basins, either empty or filled, from
floating. The buoyancy force to be offset is determined
primarily by the volume of the basin.
The principle offsetting factors include:
• Backfill materials
• Concrete hold-down pad
• Friction between the tank, backfill materials and the
surrounding soil
METHODS OF ANCHORAGE
All methods of anchoring basins use the weight of the
backfill materials to offset the buoyancy forces. The
use of supplemental mechanical anchoring methods (a
concrete hold-down pad) increases the amount of backfill
ballast, which is mechanically attached to the basin. The
recommended method of attachment is to pour concrete
grout over the basin’s anti-floatation flange and concrete
grout over the basin’s anti-floatation flange and concrete
hold-down pad (see attached illustration).
ANCHORAGE REQUIREMENTS
Requirements of anchorage, thickness of concrete
hold-down pads, as well as the size of anchors and
reinforcement must be calculated for each installation
based on the environmental conditions of that specific
installation.
Use “submerged” material weights when
calculating anchorage requirements.
Example: weight of concrete (150 ponds per cubic foot)
minus the weight of the water (62.4 pounds per cubic
foot) equals a “submerged” weight of 87.6 pounds per
cubic foot.
7: ANCHORAGE