The City of Virginia Beach needed a structure to replace a twin
barrel storm sewer that was deteriorating after 13 years in a
brackish, saltwater environment.
Contech suggested that a 10-9-in. span x 6-ft. 10-in. rise Contech
corrugated 0.125-in. thick Aluminum Structural Plate (ASP) pipe
arch be installed, and the City agreed. ASP weighs 1/50 as much
as reinforced concrete pipe, reducing assembly and equipment
costs and allowing for easy handling of long, preassembled
The City chose the ASP because of its ability to meet critical
design factors that were involved with this project. These
factors included installation in a brackish water environment, unstable soil conditions, stormwater capacity
requirements and a tie in to an existing stormwater system. The ASP satisfied all of the design requirements
and, following a cost evaluation, became the best option when compared with other pipe materials and
The solution provided a lightweight structure that was pre-assembled concurrent to excavation. Premanufactured
fittings allowed for rapid installation and connections to the existing stormwater drain.
Installation of the structure was completed on higher, dry ground and then placed in the trench in one piece
with the use of a crane.
“The installation of the ASP went very well,” noted Chris Hasty, of the City of Virginia Beach, “from the
coordination between Contech, pipe representatives and the City’s design team, the pipe delivery and
erection on site, construction by the contractor, all the way to the final lift and insertion of the ASP into place.
In recent post construction inspection, we found no defects in the ASP and it has provided exactly what we
were after in both storing and carrying larger amounts of stormwater during large rain events.”