Meeting underground detention needs on this Pep Boys Auto Parts store was a daunting task. Because the system would be completely submerged under the water table, hydraulic pressures caused by high groundwater imposed design challenges.
Project engineers chose the CON/SPAN® system - a modular, precast concrete system. With its patented 3-arch shape, it can support high live loads efficiently. Most importantly for this site, it can easily be engineered for watertightness.
Extra steel and non-shrinking concrete were used in the poured slab. In addition to normal joint material, the butt joints between the units were caulked. Joint material was also placed around the bottom where the legs were grouted to the slab.
Installed under the store’s parking lot, the vault was designed to slowly pump retained water out through storm sewers.
The straightforward design and installation of the CON/SPAN concrete system provided a costeffective solution. “It was a fast and clean installation,” said Jay Jackson of Blount, Sikes & Associates. “I believe they had a crane on the site only two days and set all the units. We didn’t have to worry about forming anything up or waiting for trucks to be pouring. I think that was the best part of it. CON/SPAN people are easy to work with. They worked on the design with us from start to finish.”