United Parcel Service (UPS) built a new $70 million distribution facility in Round Rock, Texas that will employ more than 300 employees. The regional expansion into Round Rock provides additional operating capacity for UPS in the greater Austin area, and will accommodate future growth in Central Texas.
The building’s footprint is roughly 225,000 square feet sitting on approximately 50 acres of land. With a building of this size, managing the volume of stormwater runoff from the roof and impervious pavement was a challenge.
Engineers initially specified a competitor’s plastic chamber system. Knowing a corrugated metal pipe (CMP) may be a more suitable solution, representatives from Contech reached out to engineers at Kimley-Horn to share our ideas.
The CMP solution Contech presented utilized 1,767 LF of 120’ diameter ALT2 CMP providing 140,000 CF of storage. The system uses a single 36” manifold with six barrels and was designed to account for both the current construction and future buildout.
Of particular concern to the design team was the site layout and utility conflicts that included ten foundations for lighting poles in the parking lot, eighteen parking islands containing trees, and a nearby retaining wall that had to be avoided. In addition, the site had a lot of depth and slope; burial depths (from invert to rim) ranged from 12' to 20'.
Using large-diameter CMP provided design flexibility to work around the utility conflicts when compared to the chamber solution. Additionally, the use of 120’ diameter pipe was better able to take advantage of the available depth and significantly reduced the footprint of the system, reducing both excavation and backfill costs. Durability and maintenance were also a consideration. The ALT2 service life of 75+ years and easy access for maintenance and inspection were both critical factors in selecting CMP.
A series of 36” risers were incorporated into the system to provide access for maintenance and function as drop inlets for surface runoff. This design feature reduced the number of concrete inlets that needed to be provided, providing additional savings.
While the engineers were concerned about utility conflicts, the contractor installing the system was concerned with delivery times and installation cost. Contech coordinated the system fabrication and delivery schedule with the contractor to ensure a timely delivery of all system components.