Starlite Metro Transit Goes Underground
The Starlite Metro Transit bus stop in the Brooklyn Park, MN, commercial retail shopping center was in great need of improvement. The bus stop is located in a small triangular section of a fully developed mall parking lot that was still unpaved and was serviced by a stormwater pond. Metro Transit wanted to gain more usable space for this small area to serve the busses that pulled in and out all day by replacing the pond with an underground stormwater system.
The Solution
Through an association with Royal Enterprises, Triton Stormwater detention system was selected to meet the unique design challenges of the site. In addition to fitting an extremely small and triangular-shaped area, the system had to tie into existing main inlet and outlet pipes, which were at different elevations.
The Installation
The installation was complicated because the triangular site was surrounded by roadway on two sides and a parking lot on the third—all of which had to remain open during construction, explains Lance Hoff, a water resource engineer with Royal Environmental, part of Royal Enterprises. “It was a very confined site, and it definitely was a balancing act getting the system in and working around the stockpiled materials.”
Hoff explains that the team worked closely during the initial phasing of the installation to painstakingly ensure that all the chambers met the design and installation challenges before installation began.
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| The Triton Main Header Row is assembled on the sediment base in a very confined site. |
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| With a site footprint of 14,000 square feet, the complete system provides approximately 40,000 cubic feet of storage. |
First, the crew dug down to elevation and put down a 6-inch base layer of stone. Next, the chambers were put in, and the walls of the trench were lined with a class 2 nonwoven geofabric. The site was backfilled with stone up to 6 inches past the crown of the chambers, and the geofabric was folded back and backfilled with material to the desired elevation, with the system needing to be placed under only 16 inches of cover.
The Triton system needed to be placed underneath the entire triangular parcel in order to obtain the required storage volume. With a site footprint of 14,000 square feet, 824 chambers provide approximately 40,000 cubic feet of volume storage.
From start to finish, including digging the hole, stockpiling materials, installing the chambers, and backfilling with rock, the installation took nine days.
“It was a big system and a complicated installation,” says Hoff. “But that still comes to 90 chambers installed per day as well as excavation and backfill.”
“One benefit of the Triton system that came into play on this project is its flexible and modular design,” explains Joe Miskovich, president, Triton Stormwater Systems, in Brighton, MI. “We were able to match the invert height with the preexisting pipes so as not to move pipes or tear up the entire parking lot.”
Summary
Now up and running, the Triton system is supporting steady bus traffic from early morning into evening.
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“That is a testament to its strength,” says Hoff, who adds that the modular design of the chambers allowed the crew to really pack them underneath the entire site. “We could take the chambers all the way to the edge of each row, even though they were different lengths.”
Miskovich enjoyed collaborating with Metro Transit. “The Metro Transit people understood it was quite a challenge to fit an underground storage volume in the constraints of that shape,” he says. “They were very supportive of the Triton system.”
November-December 2009
Starlite Metro Transit Goes Underground
The Starlite Metro Transit bus stop in the Brooklyn Park, MN, commercial retail shopping center was in great need of improvement. The bus stop is located in a small triangular section of a fully developed mall parking lot that was still unpaved and was serviced by a stormwater pond. Metro Transit wanted to gain more usable space for this small area to serve the busses that pulled in and out all day by replacing the pond with an underground stormwater system.
The Solution
Through an association with Royal Enterprises, Triton Stormwater detention system was selected to meet the unique design challenges of the site. In addition to fitting an extremely small and triangular-shaped area, the system had to tie into existing main inlet and outlet pipes, which were at different elevations.
The Installation
The installation was complicated because the triangular site was surrounded by roadway on two sides and a parking lot on the third—all of which had to remain open during construction, explains Lance Hoff, a water resource engineer with Royal Environmental, part of Royal Enterprises. “It was a very confined site, and it definitely was a balancing act getting the system in and working around the stockpiled materials.”
Hoff explains that the team worked closely during the initial phasing of the installation to painstakingly ensure that all the chambers met the design and installation challenges before installation began.
|
| The Triton Main Header Row is assembled on the sediment base in a very confined site. |
|
| With a site footprint of 14,000 square feet, the complete system provides approximately 40,000 cubic feet of storage. |
First, the crew dug down to elevation and put down a 6-inch base layer of stone. Next, the chambers were put in, and the walls of the trench were lined with a class 2 nonwoven geofabric. The site was backfilled with stone up to 6 inches past the crown of the chambers, and the geofabric was folded back and backfilled with material to the desired elevation, with the system needing to be placed under only 16 inches of cover.
The Triton system needed to be placed underneath the entire triangular parcel in order to obtain the required storage volume. With a site footprint of 14,000 square feet, 824 chambers provide approximately 40,000 cubic feet of volume storage.
From start to finish, including digging the hole, stockpiling materials, installing the chambers, and backfilling with rock, the installation took nine days.
“It was a big system and a complicated installation,” says Hoff. “But that still comes to 90 chambers installed per day as well as excavation and backfill.”
“One benefit of the Triton system that came into play on this project is its flexible and modular design,” explains Joe Miskovich, president, Triton Stormwater Systems, in Brighton, MI. “We were able to match the invert height with the preexisting pipes so as not to move pipes or tear up the entire parking lot.”
Summary
Now up and running, the Triton system is supporting steady bus traffic from early morning into evening.
“That is a testament to its strength,” says Hoff, who adds that the modular design of the chambers allowed the crew to really pack them underneath the entire site. “We could take the chambers all the way to the edge of each row, even though they were different lengths.”
Miskovich enjoyed collaborating with Metro Transit. “The Metro Transit people understood it was quite a challenge to fit an underground storage volume in the constraints of that shape,” he says. “They were very supportive of the Triton system.”