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By Scott Aston In 2003, the city
of Sacramento, Calif., approved installation
of the Stormvault Mitigation System by
CON/SPAN for treatment of urban runoff from
new and redeveloped commercial and light
industrial development sites. The mitigation
system is a volume-based detention and
sedimentation vault designed to treat storm
water runoff to the Maximum Extent
Practicable. The decision to install the
system in the Rovana Circle Project resulted
from the engineers’ seeking a solution for a
site that called for a below-grade storm
water treatment system.
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Storm Vault Model |
Tight site conditions called for some
out-of-the-ordinary installation techniques.
The proposed commercial building, which
was already under construction, along with
the neighboring parking area allowed no room
for a sloped excavation.
Therefore, the contractor chose to
utilize shoring to create vertical
excavation walls. Because the shoring was
rented, the contractor wanted to minimize
this time as much as possible.
Installation time was minimized by a
just-in-time delivery method of the precast
pieces. The shoring installation was
completed on a Monday, the base slab poured
on Tuesday, and setting of the units began
Wednesday morning. The units were delivered
Tuesday evening to expedite installation the
next day.
On Wednesday morning, the six precast
units were set in less than three hours
morning and grouting began midday. This
allowed for the majority of the watertight
joint sealing to be completed the same day
the units were set.
Only four hours were needed the following
day to complete the installation of the
internal baffles, piping and the rest of the
treatment system.
Solution and system
The teams from CON/SPAN, BridgeTek and local
precaster Jensen Precast, worked together
closely to execute drawing preparation,
fabrication, delivery and, ultimately,
installation.
The Stormvault structure at the Rovana
Circle site has a 14-ft span, an 8-ft, 8-in.
rise and is 42 ft long. The system now
provides storm water treatment and flow
attenuation of 2,130 cu ft for the 2.9-acre
site. According to the manufacturer, the
system’s unique water quality capture design
allows the capture of much smaller particles
and a higher pollutant load than other
flow-through systems.
The system can be designed for variable
heights and lengths to accommodate volume
and site requirements. It is also designed
site-specific for any loading condition,
including AASHTO, AREMA and aircraft, and
provides peak flow attenuation for any flow
rate.
The structural shell of the storm water
treatment vault is made up of CON/SPAN
precast arch units.
CON/SPAN Stormwater Systems
3100 Research Blvd.
PO Box 20266 Dayton, OH 45420-0266
P: 877-872-7319
csinfo@con-span.com
http://www.con-span.com
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