Table of Contents
Advertisement
INSTALLATION
6
Backfill and Finished Grade
BACKFILL
1.
Preparation of sub grade per geotech recommendations.
2.
Stabilize and compact sub grade to 95% proctor.
3.
Fill unit with water before backfilling to stabilize unit and prevent
float-out during backfilling. Secure covers and risers (if necessary)
to the unit. For units with cast iron covers, remove retainer clips
prior to burial.
4.
Backfill evenly around tank using crushed aggregate
(approximately 3/4" size rock or sand, with no fines), or flowable fill.
Do not compact backfill around unit.
FINISHED CONCRETE SLAB
Slab must extend 18" minimum outside the footprint of the unit.
Pedestrian traffic or greenspace areas: 4" Thick reinforced
concrete slab required.
Vehicular traffic areas: Minimum 8" Thick concrete slab with rebar
required. Thickness of concrete around cover to be determined by
specifying engineer. If traffic loading is required the concrete slab
dimensions shown are for guideline purposes only. Concrete to be 28
day compressive strength to 4,000 PSI. Use NO. 4 rebar (ø 1/2") grade
60 steel per ASTM A615: connected with tie wire. Rebar to be 2-1/2" from
edge of concrete and spaced in a 12" grid with 4" spacing around
access openings.
GB-1000 Installation Guide
TOP VIEW
min
Concrete Slab
4" Thick for pedestrian
8" Thick for vehicular
Rebar
ELEVATION VIEW
Finished grade
Rebar
CONCRETE SLAB DETAIL
18"
18"
min
45º
4"
8" (Vehicular traffic)
Page 7 of 8
18" min
18" min
Advertisement
Table of Contents
