Flexibility
Created an innovative design to circumvent a United States military base to meet regulations.
Partnerships
Closely collaborated with external partners to form a team with a diverse skillset to meet client needs.
Efficiency
Completed the design phase in less than a year, meeting the client’s expedited schedule.
San Antonio, Texas is full of vibrant culture and rich history. As the City continues to grow, its existing wastewater infrastructure requires substantial developments. Almost a decade ago, San Antonio Water Systems (SAWS), identified a section of sanitary sewer pipeline in need of significant improvements―but the pipeline ran directly beneath a United States Military base, presenting a challenge. SAWS and the U.S. Environmental Protection Agency agreed to a plan to reduce sanitary sewer overflows and made the decision to construct a new pipeline around the base. Facing a new set of challenges, SAWS conducted a qualification-based selection, and awarded design of the SAWS W-6 Upper Segment Pipeline to the Kimley-Horn team.
The pipeline includes 104-inch carrier pipe inside a 142-inch tunnel, as well as a total of ten construction shafts ranging from approximately 50-feet deep to over 100-feet deep. A 142-inch boring machine was used to create tunnels prior to the construction of the pipeline. Kimley-Horn partnered with Brierley Associates to complete this tunneling phase.
Kimley-Horn provided the following services on an accelerated schedule, with design completed within the year:
- Large diameter pipeline design
- Structural design
- Stakeholder coordination
- TxDOT permitting
- Large tunnel design
Due to the project’s relocation, the pipeline runs approximately 5.5 miles beneath U.S. Highway 90 West and a primary arterial roadway, West Military Drive. To avoid placing the large, 16-foot diameter access shafts in public right-of-way, the team designed the pipeline to swing outside of the surrounding interstate right-of-way, onto private property, where the shafts were placed. Kimley-Horn played a support role in the right-of-way acquisition process, working with the private property owners and the City to receive the correct permits and permissions to place the pipeline in the necessary location.
Other project design aspects include:
- Tunnel drives of over 5,000 feet
- Tunnel construction in Navarro Clay formation, including numerous faults
- Design of large diameter tunnel shafts to depths approaching 150 feet
- Design of two vortex energy dissipators, inside polymer concrete shaft structures
